I've had a battery leak in my FM4. The green LED failed. R12 2k2 was open circuit.

I have replaced these and cleaned up the mess. The unit works happily, but if not used for a week or so, the preset stations are lost. A few seconds of operation after turn on allow them to be re-entered and stored and everything is back up to normal.

The obvious conclusion is that the battery is drained if left to its own devices for too long after the unit is turned off. A quick look at the circuit diagram suggests c12 now presents too low a resistance path to earth. Barring the replacement battery being bad, would that be the obvious conclusion or is there another more obvious discharge path I have missed?

Many thanks for your thoughts.

kind regards
Marek

I got my speakers built today. I just need to figure out the crossovers. I'm attempting a 2.5 way (as I understand it) since it is a MTM. I'm still not 100% on any of it really but what phase should look like on a graph is what I'm least sure of. Phase is represented by the thin line. I'm confident that its not perfect but it's not bad either

Complete PCB SET for Douglas Self Preamplifier from Elektor [april. may, jun 1012}.
7 PCBs + all 3 ELEKTOR issues in PDF format about building the preamplifier
costs 70$ + shipping

***** Gold mine of DI¥ audio tubes schematics from Japan *****

Lucky i was to see such extraordinary DIY projects archive with vacuum tubes i share this treasure with all forum members.
Infinite THANKS for hobby amateurs in Japan who patiently scan this MJ magazine articles over the years.
Every month we get new ones available on line in pdf format
lot's of OTL amplifiers , Sakuma San articles
Et cetera

Please enjoy & respect this precious library 🙂

click on direct download link Schematic Treasures: DIY tubes audio articles HOME

and menu and titles Google Translate version in English

どうもありがとうございます
Domo arigato gozaimasu

Dissected, but far from dead:
Here lies the nerve center of an essentially brand-new Technics SL-100c:



So... Where to begin?

Browsing eBay on a recent evening, I ran across a listing to the effect of, " !!PARTS!! Technics SL-100/1500 Tonearm, Platter, Motherboard, Otherboard. "

Okay, uhhh... [clicks mouse]

As advertised, the seller was parting out a "damaged in shipping" 100c that he'd purchased "as a return." After some back-and-forth, a story emerged: Apparently someone bought this $1k+ turntable on Amazon, stripped off the stock cartridge and then returned it in the original box (minus most of the original engineered packaging). As many likely know, there's sort-of a supply chain purgatory where (literally) billions of returned items languish for long periods before being either bundled and resold or trucked off to a landfill. Never did I imagine those items to include things like brand-new turntables with ultra-accurate coreless motors that hifi mags have been raving about.

According to the seller, the unit was basically loose in the box and took a beating in transit: Dustcover destroyed, tonearm badly damaged, chassis cosmetically irredeemable, and... motor working perfectly. Unable to stop myself, I bought the motor, platter and everything you see here for a few hundred bucks.

Why tho?

Well for one thing, I've since confirmed the performance: Assembled with the motor just sitting on my desk, the RPM iphone app shows the platter running at 33.34 +0.03, w/f 0.15% (and even better at 45). That DUSTS the belt-drive deck I spent a mint on five years ago (which frankly leaves me wanting in other ways as well). More than anything, I just want to get my hands into this. I lust after classic broadcast decks, and have long wanted to join the SP-10 club (yes, I've spent a lot of time on The Incredible Thread). But for a lower price-of-entry, and given the specs above, this seems like a pretty cool alternative challenge.

And before anyone asks: Yes, I'm a bit out of my depth. I know this will cost more than I think. I don't yet have all the tools I'll need. There will be massive research and a lot of trial and error. I know there's a lot I don't know, and I'm prepared for this to take a long time.

So all that said, this thread will serve as the build log.

It's getting late, but at some point over the weekend I'll post my progress so far, my overall plan, anticipated next steps, and a few questions for the forum.

Really hoping a few of Technics Heads (and other experienced folks) will vibe with this project, follow and advise.
Cheers!

This OPA161 with Extended 200mA Current Class A Output Single OP Amp Module comes from a Chinese seller on eBay.
Does anyone have experience with these op amps?

Dear Community,

I recently watched a video about the B&C coaxial compression drivers. After looking them up i was shocked how pricey they are. Then i saw the diagram below and thought: can't we make our own coaxial compression driver with conventional cheap drivers/parts?
When thinking about the concept i became more and more excited to try.
Directivity control provided by a horn + point source behaviour like a full range/coaxial driver = why not?

Let's discuss the possibilities and try to succeed!




So here is my fist take on a design concept of a DIY coaxial compression driver (will name it CCDIY):

• HF: 1 inch dome tweeter like the Dayton Audio ND25FN-4 or Peerless by Tymphany OC25SC65-04 etc.
• MF: full range/ midrange driver. about 2.5 or 3 inches, like pdf_dayton audio_PC68 or a pro driver from Faital etc.
• using B&C phase plug design, more info in the link of the video.
• all in a tight package:

In light blue: HF dome tweeter;
In orange: basic shape of the midrange driver with cone;
in dark blue: phase plug for both drivers (is not finished, need to implement the B&C patented method for blending the HF with the MF);
in grey: front and inner channels in a housing.
Thinking about 3D printing the parts after first design prototype is ready.
Also, the dome tweeter has to be able to dissipate some heat. still thinking about solutions for that.

I'd like to present a design for a power amplifier, the main features of which are as follows:

• The output impedance can be varied from a fraction of an Ohm, to several Kilo-ohms, by selecting two resistors.
• The amplifier is stable with virtually any load.
• It is very robust, and can survive accidental short-circuits.
• Total harmonic distortion is below 0.02% at 1 watt into 8 Ohms, up to 40kHz (This is a real measurement, not a simulation).

The principle on which the design is based is that of a current (high-impedance) amplifier, using feedback to reduce the output impedance.

Full details, including a practical design example, can be found at: https://robinet.co.uk/amplifier-design.

I have attached RTA spectra plots taken using REW, showing the performance of this design at 1 Watt into 8 Ohms, and at 100 Watts into 4 Ohms.

Comments will be welcome.

As per the title really.

I work up far more designs than I usually publish on the forum or ever normally see the light of day elsewhere. Some were done at request, some are simply quick design exercises or checks / investigations, some I can't actually remember the reason for doing. I don't always have time to systematically catalogue things, and they can end up lying around on one of my HDDs for months until I sort through them. I'm currently in the process of going through one of my old external USB HDDs before it's recycled & found quite a few. Most weren't worth bothering with, but there were some more practical / interesting ones so rather than scrapping them, I thought I'd start a thread that can essentially be a bit of a dumping ground for misc. designs that I've done that either haven't found a home elsewhere, or that have previously been posted but got buried on other threads, so at least they're concentrated together.

Advance warning:

-There is little consistency in the layout / sketches. I'm lousy at CAD, and there's no way I can inflict more than a small portion on the long-suffering Dave to draw. In these cases, it's probably not worth a high quality drawing anyway. I've quickly re-saved most into png format to save space & done a little tidying if needed. The rough date is sometimes mentioned, sometimes not, depending if I remembered to add it at the time. Sometimes damping is shown in the sketch (all done in Windows Paint so they are very basic), sometimes it isn't, but I always refer to it in any accompanying notes. Same for bracing or vents / ducts; I often don't show the dimensions but they're in the notes. There may be some errors; I don't think there is anything major though. Normally I work in Imperial & assume a baseline 3/4in build / sheet material thickness. Some are metric, in which case the assumption is 18mm. Change as desired, providing the internal dimensions are not altered.

-Most of these are physically quite simple; vented box variations, some MLTLs or ML-Voigts etc.

-I'll add periodically as / when I find things. All are free for personal use.

I've been working on a waveguide project where I would develop high performance waveguides for some popular tweeters, and than share the files for anyone to print or CNC as they are able. The discussion started here: 3D printed waveguides - Techtalk Speaker Building, Audio, Video Discussion Forum for more details. The short summary is starting with the SB26ADC and a 5" waveguide, I varied flare radius, phase shields, depths, etc. I've started to find some best practices (at least with this dome/horn combo) and all future guides will have elliptical mouths, and with and without phase shields. I then skipped to 8" designs to verify those best practices scale, so anything in between should be trivial to design and still have the expected performance. Tweeters that I'm currently designing for are: SBA SB26ADC, SBA SB19ST, Satori TW29RN, and Transducer Labs N26C-A.

To get some frame of reference, here measurements of the Kef Reference 5 prototype, and Revel Concerta2 (which I suspect also uses the SB26ADC):





Here is my "C" waveguide with SB26ADC, with and without phase shield:





Quite good results I think, better than Revel achieved with the same tweeter! Anyway, the reason I am posting now though this project is still in its infancy, is I've connected with a couple gentleman with the ability to model waveguides. This could speed things up considerably, as waveguide design is extremely iterative otherwise because 90% of the performance happens at the dome/throat interface and this is not easily modeled.

We've started with verifying that the sim can accurately predict reality. With as close a representation as possible of the dome here are the results:





Extremely encouraging! I'd like to do some additional verification - particularly of the 8" guides I've started working on - and then I hope to push the sims to the max, and start producing some really excellent guides for popular tweeters.

Hi,

I just bought two pieces of Aiyima 07 TPA3255 amplifiers and also bought 48V SMPS for them. But later learnt that the manufacturer advises not to use SMPS for it but use power adapter instead. Well, first of all, what's the difference between them, technically both are SMPS only?
Click this link for the actual listing

Thanks and Regards,
WonderfulAudio

Hey you all, just looking for perspective here. I'm collecting parts to monoblock SE 2A3's and understand full well that 83 rectification (800V/250mA max) is gross overkill. That said, I have a bunch in my stash, but wonder about what if any negative sonic impact might result. As info, years ago I had a pair of Loesch Triple (parallel) 2A3's outfitted with 83's that sounded, well, pretty damn good as you might expect from the designer. Appreciate any advice you might offer.

I’ve been looking for a PA amp to convert into a 1x12 combo guitar cab for a couple of months now, and finally found what appears to be an ideal candidate for a conversion.



This amp was made by Viking of Minneapolis, and the model number is PA-93.
The specs: 12AX7+12AU7 preamp tubes, 12AX7 PI, push-pull EL84 output. Actual wattage is unknown, since I can’t find a single mention of this amp anywhere, except for a brief video on YouTube that wasn’t very informative. Viking of Minneapolis was well-known for their reel-to-reel decks, but apparently not their tube amps. The PT and OT are beefy, but small, so I’m expecting this to likely be in the 13 watt range.

The controls on the front appear to be a rotary on/off switch on the left, tone, then two volume controls for the 1/4” mic input on the front and the rear phono input. The pot all the way to the left appears to be a bias adjustment of some kind. Maybe hum cancellation?

Here’s the gut shot.

All the date codes point to a manufacturing year of 1960. The latest code I’ve seen is the 36th week, on that cap just to the right of center. It has diode rectification, though I haven’t been able to identify those either. The diodes have “IR” on one side with a diode symbol in between, and the other side says “66” and right below it says “4241.”

Here’s some other close up shots of the interior.

12AX7 input:


12AU7 second stage:



12AX7 PI:



EL84 power tubes:



The blue wire coming off the 8ohm OT tap here appears to be negative feedback of some kind. It connects to the resistor on the terminal strip and then back to the 12AU7. The OT has 70V, 8 ohm and 4 ohm taps:



The kinda cool part is this came complete with tubes of unknown origin, and they ended up being a Telefunken 12AX7 on the input, and a pair of Mullard rX1 B0K EL84 power tubes, complete with soot. The other two tubes were just an RCA and a Sylvania, nothing special:



I’m not sure what state they’re in, since I don’t have a tube tester, but needless to say I’m buying replacement tubes to use while testing the circuitry, lol. Preliminary checks so far are very promising. The resistors haven’t drifted out of spec on all that I’ve measured, and even the caps all test good, which was the biggest surprise so far. We’ll have to see what happens when they get a few hundred volts through them.

I’ll probably end up having to trace out a schematic myself, but I was hoping somebody might know something more about Viking of Minneapolis, or about any other amp that used this circuit, that might point me in the right direction. Some of these old manufacturers are really tough to find info on.

Thanks!

I have some sets of 2SA1349BL & 2SC3381BL (Hfe ~ 450).
Selling set of TEN PAIRS (10 x 2SA1349BL + 10 x 2SC3381BL) for $100 USD including postage to the US.
(Postage Tracked is $20 USD included).
If you want other stuff I have I can put it in the box (up to 250g ~ 1/2 lb).

Other Parts I have:
https://drive.google.com/drive/folders/1biIKbagCNJVCQzVrnarfznPFaL4qDL4P?usp=drive_link

I am slowly selling off most of my components so if you want some let me know.

Hello everyone,


I’m encountering an issue with my Pioneer PD-91 CD player. When it is flat, the disc doesn’t spin when I press "play," only a slight movement is visible. However, as soon as I place the player on its side (about a 45° angle), the disc starts spinning normally and playback works perfectly. Once the disc has started, I can place the player flat again, and it continues to work perfectly without any issues 😕.


I’ve cleaned the lens, but the problem persists. Could this indicate that the PWY 1004 laser is dead, or could it be another issue (spindle motor, alignment, clamp mechanism, etc.)?


I would love to hear if anyone has experienced a similar problem and if you have suggestions on any adjustments I could make to improve the situation. Are there any settings or simple repairs I could try before concluding that the laser is faulty?


Thank you in advance for any advice and feedback!

Well, the tubes forum has a photo gallery, so how about one for full range speakers?

Shamefully, I have none of my own to post yet...

"Hello to all fellow DIY audio enthusiasts!

I'm reaching out from Lake Mary, Florida, hoping to find someone with talent and experience in CAD design who might be able to lend a hand with a very exciting project for me.

I'm in the process of redesigning a somewhat older passive line array model to give it a new lease on life as an active system. My idea is to use high-quality amplification modules like the Hypex FA 123 or FA 503 to power it. Additionally, I'm optimizing its component configuration, replacing one of the 8-inch drivers with a 6.5-inch one, and modifying the angle of the rear of the enclosure to achieve more precise and modern vertical dispersion.

Although I have a clear vision of the result I want to achieve and have managed to generate the new measurements for the enclosure with the help of AI tools (ChatGPT, Copilot, and Gemini), I've hit a significant roadblock: I have absolutely no idea how to use CAD software to create the technical drawings necessary for construction. I've tried learning on my own several times, but the learning curve has been too steep, and I feel frustrated by not being able to translate my ideas into a format useful for a carpenter.

Fortunately, I have the original plans for the passive model in various digital formats, and I have clearly defined all the new measurements that I've calculated for the redesigned enclosure. The only thing missing is the magic touch of someone with CAD skills to integrate this information and create the drawings or 3D models that will allow the carpenter to do their work accurately.

If anyone in this amazing community has the knowledge and the goodwill to offer their help, I will be immensely grateful. Your contribution would be fundamental in making this project that I'm so enthusiastic about a reality. Any help, no matter how small it may seem, will be greatly appreciated!

Thanks in advance for any light you can shed on this and for the generosity of your time and expertise. I eagerly await your comments and potential collaborations!"

I have the following phase splitter designed for a 12AU7.





What components would I need to change for it to use a 12AX7 so it can drive a quad of 6V6 in push pull parallel unless with feedback I can get a 1V input sensitivity for 25 watts out with the 12AU7?

The 6V6 has a max grid resistance of 100k when operated fixed bias so the load on each output of the phase inverter will be 50k unless it's ok to use a single 100k grid resistor for two 6V6 in parallel.

for a "multi-path" DAC - but will it really do 162 dB N when level is, say -44 dBfs?

I say: no.

I call bogus 😎

https://audioxpress.com/news/imersi...analog-converter-completes-32-bit-audio-chain

You?


PS: Practically this is of course the same as just shutting off the output signal at say -110 dBfs... if you have control of the current noise in the output stage...

//

https://www.madisoundspeakerstore.c...agnetic-arc-oxidized-full-range-matched-pair/

Given the small size, nice FR as posted and decent sensitivit, I’m considering trying them as midrange drivers in a three way. Just looking for anyone’s personal experience with them. Thx

I have decided to try to sell some of my first DIY projects.
This is the Millett Engineer's Amp. If you don't know it, read about it on his site.
The chassis is hand made from steel and "thermory" Ash (Kiln treated Ash).
The Iron is from Edcor, I just like to re-patina the covers.
I am asking $450 (plus shipping), which is basically the cost of parts. I would prefer to sell locally, if possible but I am located in Santa Fe New Mexico, so that might not work out. If you are interested but would require shipping in the US, feel free to message me.

Cheers,

I am starting the ACP+ build thread.

I have posted the documentation for the ACP+ preamp/headphone amp
which is the subject of the DIY build session on Saturday Nov 9 at the
Burning Amp Festival.

https://www.firstwatt.com/wp-content/uploads/2023/12/art_acp.pdf

I have assembled a total of 55 kits for the occasion, of which I
understand 30 will be built on site and the rest distributed in some
fashion.

Our member 6L6 has been working on his build guide as well.

As with the ACA, I anticipate it being available in the store soon.

Pete Millet Sound Card Interface
&
Soundrite 2i2 USB Mic preamp

Selling a set consisting of a Pete Millet Sound Card Interface, along with a Soundrite 2i2 USB mic preamp, plus cables.
This combo gives an easy-to-use interface for audio measurements using a PC, via software like Arta, VirtuixCAD, Room EQ Wizard, Audiotester, etc.

Pete Millet designed an interface that does the following to simplify using a PC as an Audio Analzyer:

• Able to accept a wide range of voltages and scale them for the sound card input
• Survive over-voltage inputs without damage
• Provide AC-coupling to protect from DC voltages (like plate voltage on a tube stage)
• Provide a reasonably high impedance input, preferably with some ability to make floating measurements
• Buffer and amplify the sound card output, with very low distortion and low output impedance
• Provide a calibrated true-RMS AC voltage measurement

The Sound Card Interface is only available as a kit, this is built and tested, ready to go.

The Soundrite 2i2 is a modern, very low-noise floor USB mic preamplifier a/k/a/ 'Sound Card' which complements the Millet interface. It has a 120dB dynamic range, which really helps turn this combo into a professional tool for audio measurements.

With this combo (plus software that is not included, but some of which is free), one can do:

• Spectrum analysis with Fast-Fourier-Transformation (FFT)
• Sweep measurements
• Measurement of Distortions vs. Power
• Frequency response measurements
• Distortion, Level Analyser and THD+N with several filters
• Measurements of harmonic distortion

Asking $250 for the set including pictured cables.
($150 for the Milllet SC Interface, and $100 for the Soundrite 2i2)
Shipping from Saint Louis, MO 63108, at my cost.

Hi all, I’ve been enjoying my first DIY amp quite a bit, bringing it out for several gigs, tweaking a few things here and there, and seeing a trajectory of steady improvement with the voicing.
However, there is an issue which I don’t know how to address. I’m hearing an extraneous noise accompanying certain notes, it’s a kind of crunchy rumble. Sometimes I think I’m hearing a distorted sub-tone an octave down.
It only happens on certain notes, and they seem to correlate to mechanical resonance which you can hear if you tap on the tubes or the chassis. The same pitches you hear when doing this, can sometimes get excited into a slow feedback type of noise. The same pitches, when you play them on the guitar, get this extra crunchy whoosh-y rumble added. It doesn’t seem to make a difference how I set the volume on my guitar vs on the amp.
These are behaviors I can notice while playing at home. They’re maybe a bit too subtle to be noticed on a gig scenario. I’m playing louder on gigs, but there’s also other musicians playing and it just gets buried. It would doubtless be a better if the amp didn’t do these things.
Attaching the schematic. V1 is a C3G and yes I’ve got it running at really high gain, but again the offending sound doesn’t seem to care how hard I’m driving the input.
V2 is 6SN7 and this one seems to be the most sensitive, microphonically. The resonance seems to be localized there. I’ve tried swapping in different 6SN7’s, they all act the same. Drivers are 6SL7 and outputs are KT66. Generally the amp sounds pretty good, I’m just pleased it works at all, let alone well enough to play out with.
I hope that someone recognizes the behavior which I’ve described as best I can. Thanks for your thoughts.

Excellent condition. Just a NC252MP in a nice box. Had been using it to power my main speakers, but upgraded to Nilai monoblocks. Thought about keeping it to power subs, but decided I didn't need something this fancy for that purpose. $375 shipped CONUS

https://www.audiophonics.fr/en/powe...tereo-ncore-nc252mp-2x250w-4-ohm-p-14185.html

https://www.audiosciencereview.com/forum/index.php?threads/audiophonics-mpa-s250nc-amp-review.45306/

Hello Audio Enthusiasts! Some of you may know my work on www.audiocircuit.com, where for many years I have been helping to advise Acoustat owners. I was an engineer and manager with Acoustat, starting when the David Hafler Co bought Acoustat out of bankruptcy, right up to the very end of US production under Rockford Corp ownership (sad day that was!). So I thought I'd lend a hand here, too, because I LOVE Acoustats and want to help as many owners as possible to keep their Acoustats running for many years to come. I don't sell parts or do repairs, but my advice is FREE! So let me know how I can help YOU with your ACOUSTAT's! (And this being a DYI crowd, I don't mind discussing modifications to the speakers.)

Andy Szabo

I have been scouring these forums for the past few months as my sons and I have embarked on a loudspeaker design project (two projects concurrently, actually). We have finally run into a roadblock which I don't know how to resolve and have concluded it is time to join the forum officially and seek some help!

We are an American family residing in Riyadh, Saudi Arabia.

Here are simple blender images of my two sons' designs:

Looking forward to my first visit to the Hamvention, is anyone else going or setting up booth? Making my tube list for the flea market. Coming with my wife. I did notice that George of Tubelab is on the vendor list, it would be awesome to meet him! Or any other small businesses here going.

https://hamvention.org/

I have this speaker that stopped working and put my Yamaha into protect mode . I took it apart once but couldn’t find a x over or anything??? It seems a cord got loose and i attached it to the wrong spot .

Look at these two circuits. They do the same.
The difference is the single and the dual supply.
Another difference is the capacitor C1 and C3.
Because the negative voltage at input pin C3 should be put 'upside down'.
This goes for all bipolar opamps with NPN input transistors.
And when using dual voltage supply.
If a bipolar opamp has PNP transistors input the C3 should be turned the other way.

Well, origin thread is here : Iron Pumpkin(s) and other smaller vegetable animals

If nothing else, read at least first several posts on linked page , to grasp enough info about concept itself.

This one having two purposes :

-placing all necessary info about final iteration,

-trying to layout clearer picture of what's fuss about,

-with edits of this first post - making comprehensive list of tips and tricks and funny fine details , and answering on any clever or dumb question you'll possibly have ......either here or further in thread

(3 purposes then , not two )

edit at 22.05.2020. short how-to-do for Iron Pumpkin SE, referencing to post #2:

do not connect buffer output to Turtle

maximize trimpot R36 (measure across R39 to confirm max value)

R37 position is irrelevant for now

if you're sure that you connected everything properly, just power it on

set positive and negative rails to +/-12Vdc , with trimpots R9 and R10

power off, place DVMdc crocs across R34, power On then fiddle with R36 to set 20mV across R34, then fiddle with R37 to set 0mV DC offset at output


do everything the same with other channel, connect outputs of buffers to Turtle, enjoy

In the past years, the cost of CNTs has gone down radically while their purity has gone up. CNTs can be expected to far outstrip carbon fiber in their strength to weight ratio. Of course, making a speaker cone out of CNTs (only) directly is not practical because CNTs don't stick together well. However, CNTs are known for as much as doubling the strength of other materials. Common articles assert that only 2-3% CNTs by weight is required for drastic improvements. So I purchased some CNTs that I intend to include in a coating for speaker cones. It was like $75 for 100 grams whereas early on they were more like $50/gram ballparkish. .. clearly enough to do many cones. .. The challenge according to articles is that CNTs don't dissolve like solutes. They have to be dispersed using special solvents and usually stirring and ultrasonics. Otherwise, they clump up and cause more trouble than gain. So I haven't tried this yet, but I think it would be more fun to toss some ideas around. Articles have indicated that multi-wall tubes work better for strengthening other materials so that's what I got. I'm planning on sanding just a little paper off of some paper cones and then replacing with a thinned CNT based coating .. Polyurethane is on the list of possibilities as experiments have been done with it already. So let's see if anyone has any cool ideas about the best way to do this so I can make the best decisions before taking little risks. I intend to do trial runs on useless paper or cardboard.

This all started with my 'Convergence' project on a quest for a great bandpass design using a PR as the exit. Initially it was a TB W8-1445A (one-off production sample from the Tent Sale, and also this next item too) and an Eminence 12" PR. I wrote up the project here:
Techtalk Speaker Building, Audio, Video Discussion Forum

I had enough output with the 200W, but the extension on the bottom was lacking. It was made known to me of a commercial company, James Loudspeaker, that sells this kind of design commercially. This only fueled the desire to make this a viable little monster. It was well liked at InDIYana 2017.

Then I went to dig deeper...

I got a UM8-22 and RSS315PR, removed about a 0.25" for the mounting hole, coined the project 'Overdrive' in the same box, and got a little more extension, but the output then suffered. It seemed like where the amp was peaking out was where the design finally hit enough output on the 200W amp. I had a thermal driver failure in this setup, but ultimately do not know what the initialization of that traumatic event was. It could have been amp clipping, or just an inability to expel the heat being the kind of design this is, but I don't feel it was due to wrong box, or overexcursion. I had a replacement in it after that, and never had a problem up to removing it last weekend to make the retrofit explained herein happen for the finale of this 3-year design process. The models did not predict any issue to be concerned about before commencing down this previous path, and I've had several people review them just as reassurance.

I feel if you have a smaller living room or bedroom and require a subwoofer that either of these above would likely be sufficient, and the box isn't big at all. This was definitely a case for Hoffman's iron Law in terms of output vs Xmax.

And now the finale...

About 6 months ago, I started looking for another upgrade path to improve this design and make it what I want from it. On a whim, I modeled the UM10-22 in the same box, and to my surprise I might add, it basically gave me the same result the Um8-22 yielded in terms of response. The improvements were mainly in Sd, Xmax, power handling capacity, and nominal sensitivity. So- same response, but more and better of the 4 specs just stated. I'd call that a win!

I waffled over whether to take the plunge for a good bit of time, because not everyone is happy with this line of subwoofers. It wasn't until there was a sale on the Yung amplifiers in June that I had to make up my mind quickly. Rory was in town around that time, and we had a discussion about this project and the possible options, and he felt my aim was true. I had a lengthy exchange with MattP at PE via PM about the possible reliability concerns of both the amp and the woofers because he has had them himself, and likely not been totally congenial with them. I'm sure he put them to task. He said the 10 was a worthy step-up, and take boosted low end very well. He also said they have not had recent issues with the Yung amps. Since it came from the horse's mouth, I was reassured and bought the Yung SD500-6 amp right before the sale ended. I then picked up the UM10-22 at the Tent Sale a month later for a reduced price.

Now with supplies in hand, I had to modify the box. Most of the time when retrofitting, you just get out the jig-saw and cut a larger hole. Being this is a bandpass, I could not just do that. So after old-units removal, I had to slice off the front chamber of the box. Then I used the former 8" mounting holes as bridge mounts for the false-center. I marked the center using the corners of the box since it's a square x-section, and routed a new rebate, followed by a new through-hole. I marked and drilled mounting holes, and then I biscuit and glued the front back on. Of note- the driver does fit through the PR hole, but barely! I'm glad I had both sides of the driver accessible to position the driver appropriately, or this would have been extremely difficult.

Then I had to cut the new amp through-square, and I'm only lacking about 0.75" in dimension from taking up the entire rear panel. I had to remove the 4 braces I had glued in for the last iteration, and then glued in 2 new braces per side of the box for strength and resonance control.

I used a 4-pole terminal block for connection of amp to driver. There is a bridge connecting the center 2 connectors so that the DVC is connected in series. As for wiring, I wanted something really solid. The UM series takes banana plugs, and I had a set of "polycarbonate locking bananas" and some 2/16 Belden Brilliance wire handy. I used both wires for a net-13AWG assembly per terminal, and CRANKED on them in the jack with a pair of pliers to make them tight. Then I heat-shrunk the banana to jack connection for ultimate durability and keep them from coming apart. I wasn't going to use them for speaker cables, as the locking types tend to break with repeated use, and IMO are kind of a pain to undo and reconnect. I deemed this an acceptable use for them since they would only be attached once.

So- there is the process of this build. Now for the grit in numbers and graphs (see below), as well as some assembly photos of the adaptation.....

Model, along with the amplifier boosted response and inherent highpass pictured below. I found this perusing AVS forum via google looking for just this answer. It therefore does extend below the 30Hz highpass with the boost applied from the preamp board. Note that Unibox is capable of modeling this in segments, and I've pieced this image together to show it in one image.

The finger access rebates are a wise thing to include if you ever think of removing a driver this heavy from a box so small and tight.

Now that the arduous computer modeling was done, and the hair-pulling had subsided, it was time to relax and listen to some music as well as also pummel it with a movie. I have it currently positioned on the floor in front of my entertainment center, just to the left of my right front. I played a movie soundtrack or 2 with some good music songs, and then flipped the phase knob to 180 as something just seemed off. Initiate beat lockdown! All of a sudden it roared to life in my setup. I don't know for sure, but I might have hooked up the amp in reverse to have caused this, or it was just needed to get the summation right. With a 4th order rolloff on the Fenrir on the stands, and the likely 4th order acoustic plus 4th order active rolloff on the sub yielding an 8th order total rolloff, it's hard to say without tearing it back open. The Anthem is at +3 on the sub-out as stated, as it helps to engage the auto-on circuitry that is not able to be bypassed. Gain on the Yung was set at about 1:00, and the xover about 11:00. When I fiddled with it, the sound didn't change much above there due to the inherent rolloff.

I was using the 'Batman and Robin' soundtrack, as I know it quite well. R. Kelly's 'Gotham City' has very dynamic hits, and that just sounded wrong, along with Smashing Pumpkin's 'The End is the Beginning...' never sounding thin like it was this time around. Then there is Jewel's more emotional non-album version of 'Foolish Games' that has a very tonal bass line. Important or not, it's a good disc to own. I then popped Bass Mekanik's 'Download' in to see what it as capable of. 'Out of this World' has a dropping sweep to 10 cycles, and it handled it quite well with a slight Xmax reduction just below the HP rolloff, but it never cut out completely. Then Moonstone with the dominant 27Hz frequency really made this thing shake out the bass. The 8" would have complained, but this thing held its own.

Then I popped in 'Independence Day: Resurgence'. I know the UM8 played this movie with a bit of struggle, but took it just the same. The UM10 on the other hand is a MONSTER in this alignment. I had bass for days and then some. I was really shocked and the jaw popped open a few times because of it. In fact, this is the best bass I've heard since either; 1- I ran Marianas, or 2- Matt ran his dual 18TBX100s. Tight and tuneful, and never sloppy, this thing made explosions in movies sound like they are supposed to. It was fine at the same level setting as the music, but felt it was a little overblown in output, so I dropped it to 12 noon. I'm really pleased with this endgame, as it does what I'd hoped it was capable of doing. Bandpass designs are really low distortion alignments as long as the port turbulence is accounted for, or replaced by a PR as in my case.

Some additional notes:
-If this amplifier is to be placed on a sub on a room boundary, or even in a corner, I would think hard about using the non-boosted amplifier, or even shorting the 2 caps out that provide the main boost on the preamp board by way of a DPST to make it an optional +4dB at 25Hz. The secondary boost is provided by the 30Hz highpass filter at about 1.2dB of gain. I learned this over on AVS forum here, useful starting at about page 3:
DIY Speakers and Subs - AVS Forum | Home Theater Discussions And Reviews

-This 'Overdrive10' design is assumed to be flat theoretically to 22Hz with the boost engaged as-is. The amplifier response profile along with the supposed anechoic non-boosted response above in the model plot, and it should be pretty close, barring room gain changes.

-If making a bandpass sub of this type, or even just a PR box, I highly recommend measuring the tuning with an impedance sweep to verify it is as it should be. Being the nature of the bandpass beast, having it off by 5Hz can really impact the extreme rolloffs of the design.

-Spikes might be a requirement due to how much this thing shakes when it operates.

-Unfortunately, this is not a cheap sub. $169 for the woofer, $90 for the PR, and $238 for the amplifier. I got the PR for $16 and the woofer for $136 at the Tent Sale, and the amp for $200 on sale, not counting the other drivers and passive that I tried out in this configuration. The Yung 200 I had was a door prize at MWAF that started this ball rolling 2 years ago with the Convergence drivers I already had. It's been a long case of R&D this time around.

In conclusion- I'm happy with this version, and will likely leave it naked MDF for a good bit dreading taking it apart to finish it and not have the bass presence for that pending period of time. At a gross volume of just over a cubic foot, I personally have not heard a sub do what this thing can, outside of being in a car. It can be loud, do it cleanly, and plumb the depths. I couldn't ask for more, except maybe a second one! Really though, one is enough.

If you have any questions, please just ask.
Thanks for looking!
Wolf

This project is a Group Buy. The public group here must agree - in this thread - on what parts will be sold, by whom, and where. Members must abide by those agreements. Any regular sales of the Group Buy PCB, kits or other specific related items outside of diyAudio or this thread will result in the removal of that person from diyAudio.com This is completely at the discretion of the Moderation Team.

No one shall send unsolicited or blind sales PMs to anyone else on the forum. This has long been against the rules and will also result in the immediate banning of any person who does so.
Keep this Group Buy clean and noncommercial or risk immediate removal from diyAudio.com.

---

---

Hi Guy's

Please Register your details for the Wolverine 4th group buy - Pre Order









Each order will contain:

1. The PCB’s that you ordered.
2. An A3 copy of the schematic. Both 57V and 64V rail voltage versions have been created. (Dropbox Link)
3. The Build Guide, which is a 32 page illustrated A4 color document. (Dropbox Link)
4. BOM in excel, listing all the components and mouser part numbers required to build the Wolverine. (Dropbox Link)
5. Hole Pattern DXF file and 1:1 PDF file of the Hole locations for Heatsink drilling. (Dropbox Link)
6. How to wire a Audio Amplifier. PDF document by Bonsai showing Audio Amplifier wiring best practices. (Dropbox Link)
7. Any future updates to the Build Guide, BOM or Schematic will be updated in Dropbox Link for you to download. So please include the e-mail address you would like to use for this purpose.

To Register your details

1. The total number and type of each EF3-3 & EF3-4 boards you would like.
2. Your full name, full postal address including country and post code,
3. Please include your Phone number for tracking updates once your boards are shipped.
4. Your PayPal e-mail address
5. Your personal e-mail address for the Dropbox documentation link to be e-mail to you.

Once a reasonable number of boards have been pre-ordered we will order them from our P.C.B. supplier.
We will keep all forum members up to date on the progress of the group buy.

Once we receive the boards we will pack them up, calculate shipping and then send out the payment request to each forum member.
Then once payment has been made you will receive a tracking number so you can track your orders arrival.

Please don't use my e-mail address for any other purpose as I don't have time to respond.
Please post any questions regarding the build of the Wolverine to the main Wolverine Build thread on the forum.
Please post any questions related to ordering through to me using the DiyAudio PM system.

You personal information will not be used for any other purpose and won't be passed onto anyone else.

Kind Regards
Stuart & the Wolverine project team.

Wolverine development Thread

Wolverine Build Thread

Youtube build series


We're are also excited to share some great news, which we hope will enhance your amplifier building experience.
The Wolverine team is thrilled to announce that anodized heat sinks are now available for our project.

These heat sinks are specifically designed to fit perfectly with our current boards. Here's what we've got:

• Heat sinks suitable for the IPS Boards V4.9.
• Pre-driver heat sinks designed for V4.2 of the EF3-3 & EF3-4 Output Stage Boards (OPS Boards).
• Driver heat sinks for V4.2 of the EF3-3 Output Stage Boards.

We are offering full sets of these heat sinks, which include installed Mill-Max pins:

• EF3-3 IPS, Pre-Driver & Driver: $27.5 USD (6 Heatsinks Total)
• EF3-4 IPS & Pre-Driver: $22.5 USD (4 Heatsinks Total)

Thank you for your continued support of the Wolverine projects. If you have any questions or would like to place an order, feel free to reach out via PM.

@jjs is in the USA, and I am in Australia, so please PM whoever is closer to you, and we'll arrange some for you.

Happy building!

Best regards,
Stuart & the Wolverine Team

I am happy to present you with a project that I did 5 years ago which has served me well since.

---

• The Equalizer for Full Range Speakers Essentials Kit is available in the diyAudio Store.

Due to a clerical error on my part, I now have 4 pairs of 2 way monitors going spare. Wharfedale delta 30.2, mordaunt short ms20, mission 731 and 732.

In my house, I like to have two systems. One for the office, and a surround sound for the TV (got a standard 2 channel amp for the office, and a 5.1 avr for the TV, I'd upgrade to 7.1, but I'm really not sure if it's a good idea for the space).

Originally, with a spare amp too, I was going to give away one pair, keep one pair (most likely the 732s), and sell the other two, but I was tinkering with some of them the other day, and I was really enjoying the difference in the characteristics. I won't say they're all on the same tier exactly, but they're not that far apart, and I do enjoy the variety, even if they're not crazy different.

Recently, I bought this pair of custom speakers. Way cheaper than they should have been, and absolutely massive. I think the previous owners liked them for parties, and I got a horrible overpowered amp for the asking price thrown in for free. Thankfully, it plays nice with the avr, and the added depth it gives the sound at not insane volumes (I like my neighbour, and it's a semi detached, what can you do) is very nice.

It had me thinking "how hard could it possibly be to whack some MDF together, do maybe 5-10 minutes of soldering, and unscrew drivers for transplanting".

I did do a little research, and the advice seemed to be "why would you do this", but I guess I'm just after answers with my specific set up.

My current thinking was:

1) don't mess with the 732s. They're nice, I like them, perfect for the office. Keep those as is (once I've repaired a tweeter).

2) give away the 731s + amp. It's getting a bit silly having this many unused cabinets lying around.

3) unholy Frankenstein combination of what, iirc are some wharfedale lasers (please don't make me walk downstairs to find out which) I'm using for rear surrounds in the TV set up, the mordaunt short ms20s, and the delta 30.2s into a disgusting mttmm or mtmm floor standing speaker, then flog the unused parts on the bay. Potentially add a woofer for fun too, then use them for my rear surrounds in the 5.1 set up.

What I want to know, is on a scale of 1 to 10, 1 being bad, and 10 being good:

1) how good/bad could it sound
2) how much will I regret my decision on this as a project
3) chances of success? (Part time tinkerer + audio refurbish and repair. I won't say what I achieved is aesthetically pleasing, but I also won't say I care, or that it doesn't function)

Answering a few of your questions in advance:

-this is a waste of time. If you want floor standing speakers, why not buy a kit, or just get some off eBay?

For the same reason that god made grapes but not wine, and milk but not cheese, so that we might share in the divine act of taking something cool and making something stupid but tasty

-why not sell the speakers that you have, and get more sensible drivers at the very least?

I'm emotionally attached to some of them.

-that doesn't explain why you're okay chopping them up for parts... How about this, why not sell two pairs and your avr, upgrade to 7.1, and then you get to keep more of them?

For 1, the room is already pretty unbalanced to begin with, and it'd be too big of a job sorting that out, and for 2, it really is a space thing at the end of the day. The spots where the surrounds are at the minute could go up to the ceiling, but it'd be a bad idea to remove square footage.

-interesting... Sounds like that's quite a small room, why do you want such big speakers then?

Mind your own business. For reals, depth of sound, clarity, quality e.t.c. I'm not here to blast my, or anyone else's ears off, but I do like nice sound. Also, I can see myself moving in the not too distant future. While I'm not above paying silly money for larger removal vehicles, or doing some to-ing and fro-ing myself, I anticipate my views on sound aren't going to change anytime soon.


Also, fyi, I will be looking into wiring kits, I think whatever configuration I end up doing won't really lend itself to reusing any of the existing ones.

I am looking to make my horn-loaded D54 2" Midrange Domes a non horn-loaded flat D54-AF midrange to widen the bandwidth at the expense of 2dB sensitivity.

It looks like the older Dayton DC50 which has a 3 screw hole connection for the flat faceplate to the magnet / voicecoil assembly will WORK as well.

Let me know if you have a pair of dead tweeters (D54 AF/ D52AF / DC50F) or these associated Flat faceplates to sell.

I have a US mailing address and I can pay via PayPal.

Regards,

Dan

Hi all, a while ago I purchased a very lightly used set of, all Morel, ET 338, CAW 538 and CAW 938. My intention was and still hopefully is to pack these drivers into a nice 3 way speaker.

I have been learning VituixCAD but am a bit stumped with designing an enclosure for the CAW 938. I have a few questions about this regarding simulated SPL, Xmax and overall rules around these topics.

• • What SPL should these speakers be able to play up to, as in max db SPL for loud listening in a medium to large lounge at between 3-5m listening distance? Or if there is a standard for general high end home audio speaker I would be happy to aim for that.
  • In terms of woofer roll off at what point do you not need to worry about cone excursion, weather that's referencing the SPL roll off, the power dip at the impedance spike, cone force or velocity. I have looked around but cannot find any solid information on what is safe in terms of Xmax, everything from sealed enclosure to bass reflex and band pass all pass the rated Xmax of driver even at fairly low wattage, why is this not a big concern. What are some good rules or parameters to follow in terms of this while getting the desired SPL output.
  • I really want to do a nice job with these speaker as it will be the first I have designed myself and will be my daily drivers. Keeping this in mind they will be mainly used for music and watching movies. I would ideally like the qtc to be reasonably balance around 0.707 to avoid sloppiness or compression.
  • I have built and done some measurement on some test enclosures. The volumes and dimensions are listed below:
  • CAW 938: 320mm x 730mm x 436mm, built in 18mm OBS, the volume is 76.5L with a qtc around 0.71.
  • CAW 538: 260mm x 320mm x 210mm built with the same 18mm OBS, the volume is 10.5L giving a qtc of 0.5 to hopefully keep the mids nice and dynamic.
  • Finally, is the CAW 938 not suited for a low range woofer, my initial goal was anywhere from 500 to 250Hz down to the driver roll off with no HPF. If this does not seem viable I could definitely use it for a 2 way using it with a beyma compression driver.

Please correct me if I'm wrong with anything above. Please see some enclosure simulations below and also some nearfield measurements of the CAW 938 and 538 test enclosures, these measurements are also gated from memory.

Hopefully this data is enough to go on, let me know if not or you need any more info. All measurements in REW have 1/24th smoothing applied.

EDIT: Sorry I also forgot to add the nearfeild accuracy cut off's.

• CAW 938: 655Hz
• CAW 538: 1023Hz

I will also not these measurements where not measured at a specified power level, 1 watt for example, they are quick and dirty just to give an idea of what the drivers are doing. The 538 enclosure has been filled with polyfil but the 938 enclosure doesnt have any.

Thank you!

Friday evening chez Weldon:

Start with a warm winter evening and a bit of a sunset
Add a glass of red, a shot of hooch
and a couple Dungeness

thread index at the end of this post!

When planning, simulating, building and measuring bass reflex enclosures for 2-way speakers one difficulty is dealing with port resonances in the midwoofer’s passband.

I thought it should be possible to absorb resonances with Helmholtz resonators in/at the bass reflex port.
Obviously I am not the first to come up with this idea, but I also didn’t find very much about it on the internet.
Thus I decided to make my own measurements, see the following posts!

some web references:​

Short thread about this issue on diyaudio. note that the thread starter wrongly refers to the "1/4 wavelength resonance" of a port. This is not correct! The fundamental resonance of an open tube happens at the frequency that has a wavelength equal double the tube length.

A german thread about port tube resonators.


various web references for resonance of open tubes and helmholtz resonators:

https://en.wikipedia.org/wiki/Helmholtz_resonance

https://en.wikipedia.org/wiki/Acoustic_resonance#Open_at_both_ends

https://www.physicsclassroom.com/class/sound/Lesson-5/Open-End-Air-Columns

https://en.wikipedia.org/wiki/End_correction

http://troelsgravesen.dk/vent_tuning.htm (including end correction values!)

calculating resonance of bass-reflex port (open tube resonance):​

occurs at frequency that has half wavelength equal to end corrected reflex port length and respective frequency multiples.
Oscillation node (pressure maximum) is at center of port (or further divisions for multiples).
pressure absorber works best at the respective node.

Option 1: tube absorber​

Simple tube, one end closed, it should thus have roughly half the length of port for absorbing resonance of port fundamental; can either be parallel (and inside) the port or 90° perpendicularly mounted at port. Open end should be located at half port length.

Option 2: Helmholtz absorber​

Mounted at half bass reflex port length, connected by its own small Helmholtz port to the bass reflex port

-------------------------------------------------------------------------------------------------

Thread index​

#3 - first resonance absorber tests with tube test setup
#5 - decay plots of test bass reflex box
#8 - resonance absorber results by @augerpro
#11 - link to a relating message by @rdf including link to roozen/philips-paper
#19 - new parallel 6th order bandpass test box for further investigations
#22 - dealing with enclosure resonances
#25 - chuffing audibility test
#42 - particle photos (using water sprayer)
#48 - port 2 variants and measurement results
#50 - port stalling test
#54+55 - influence of smoothed port flange
#56 - port 2 impedance results
#58 - port resonance absorber test
#81 - link to bryce doll paper by @Hearinspace
#103 - port 2 variants resulting in the same tuning frequency, with geometry drawing
#104 - photo of port 1 variants
#141 - port wall stiffening influence
#157 - port 1 variants response measurements
#159 - chuffing RTA measurement of straight port 1
#161 - chuffing RTA measurement of rectangular curved wall port and big 3d printed port
#165 - chuffing RTA measurement of flat port and small straight port
#166 - resonance absorber setup
#167 - measurment of resonance absorber lenght variations
#202 - resonance absorber filled with melamine foam
#206 - chuffing RTA measurement of 3d printed port with resonance absorber
#214 - influence of port diameter/dimension for enclosure resonance transmission
#228 - small 3d printed port drawing and measurments
#230 - testing noise of roughened port surface
#236 - port with resonance absorber documentation by @Kwesi
#249 - chuffing RTA measurements in singe dB steps (small 3d printed port)
#251 - separating resonance absorber from the port with latex membrane
#288 - link to salvatti devatier button paper
#302 - explanation of boundary layer thickness by @andy19191
#310 - impedance measurements for port 1 variants at different input levels
#320 - "progressive port geometry" concept
#324 - progressive geometry port measurements
#328 - progressive geometry port length correction
#329 - progressive geometry port impedance measurements at different levels
#330 - progressive geometry port response
#331 - progressive geometry port chuffing RTA measurement at 100 Hz
#341 - output level measurement / comparison
#349 - is airspeed the main chuffing factor? progressive port chuffing RTA measurement at 50 Hz
#350 - new particle photos
#352 - explanation of turbulent air motion by @andy19191
#363 - relating chuffing to particle displacement
#367 - first GIF-excepts of 120 fps particle videos
#390 - port variants with sound recordings by @Tenson
#391 - correct port particle displacement calculation formula by @David McBean
#395 - (1) first slow motion video: hard edge port
#407 - (2) second slow motion video: flared port
#434 - flange variant video
#438 - (3) third slow motion video: progressive geometry port
#448 - influence of air particle displacement for the excitement of low frequency noise
#449 - differences of a big and small (optimized) port for a small 2-way midwoofer
#460 - (4) fourth slow motion video: small straight hard-edge port
#468 - small very flat port - checking for boundary layer flow resistance
#503 - how to calculate the strouhal number using max port air velocity data, CORRECTION see #591
#504 - water tank simulation
#522 - @Dmitrij_S Karlson couple port
#526 - flared port geometry definition
#529 - 2 way speaeker test ports to be measured ...
#531 - ... response measurements ...
#546 - ... chuffing measurements (RTA) ...
#591 - correct calculation of strouhal number, related to peak-displacement instead of p-p- displacement (thanks to by david mc bean)
#595 - how to find a suitable port exit diameter using the Strouhal number (corrected version!)
#616 - first beta version of a simple excel sheet for tuning calculation of NFR=0.5 ports
#621 - relating the strouhal number to compression and distorsion
#624 - parametric fusion 360 model for a NFR=0.5 port by @augerpro
#627 - augerport with resonance absorber by @augerpro
#646 - parametric NFR=0.5 port model for freeCAD, including STEP and STL model
#652 - announcement by @David McBean: stouhal curve included in the port exit air velcity graph.
#654 - how I make my 3d printed ports
#680 - chuffing/noise audibility comparison: straight and flared port
#704 - big collection and evaluation of 3 speaker and 14 port variants - proposed MID PORT STROUHAL NUMBER (MPSN) parameter
#747 - updated excel calculation tool with correction and variable NFR ...
#748 - ... and the imperial version of the same calculator
#753 - comparison ports vs passive radiators
#811 - compressing the optimum geometry definition to two relevant parameters
#812 - The breakthrough: Finding compression behaviour patterns
#847 - Iterative port geometry optimizer tool


(will be updated)

Hi everyone!

I'm planning two (maybe three) fun speaker projects and would love input from experienced DIY speaker builders – especially if you’ve worked with FaitalPRO, Beyma, Fostex or Morel drivers (those are the only ones I have access to order..).
Passive radiators from other brands are fine. DSP, REW and measurement mic are available for all setups.

---

Project 1: Mini 2-way + Mini Subwoofer for my boy’s room (16 m²)

Small Satellites: max 150 mm (W) × 250 mm (D) × 300 mm (H) – smaller is okay.

Mini subwoofer: Can fit either 600×500×230 mm under the bed, or 540×400×230 mm under a shelf.

I want something fun, with real bass, but not necessarily high SPL. Think “mini system that feels like a big one.” (Electric music)

Full DSP control – so EQ, crossover, limiter etc. are available.

Fun factor is key. :-D

---

Project 2: Subwoofer for high-end home theater (35 m² room)

Enclosure limit: 500 × 300 × 500 mm (~75 liters gross).

I already have a Velodyne DD-10 (Gen 1) and want to complement it – more depth, punch or both. (and front ELAC FS-249 (gel1) )

DSP + 700–1500 W Class D amp available.

Passive radiator or sealed design preferred (ported is tight on space).

Priority: Deep extension, musicality, cinematic power, and clean performance down to 15–20 Hz.

I might be able to increase the box volume a bit if needed.
---

General questions:

Which drivers from FaitalPRO, Beyma, Fostex, or Morel should I take a closer look at?

Are there any particular models you’d avoid?

I feel like I'm stuck 😕

Good Evening everyone. So am piecing together a rebuild of some speakers for me to use and listen to from my dad years ago. It’s the Sansui SP-100’s. So I have a few drivers I can use but, didn’t know if switching out the 5” inch sealed Midranges (or squawker’s it’s called on the crossovers)for midrange domes is with it? They are crossover at 1,000 Hz and play to 5,000 Hz. So Am rebuilding the speaker from the ground up. It will take some time but, that’s okay. Am looking at the end of the completed project and what I want it to sound like now. So here are some Brands and the model numbers am looking at?

1. Ciare HM-130 (It’s a 5 inch sealed midrange). $100.00 each with tax and shipping to my door. I have to order it through the company only.

2. Visaton MR 130 (It’s a 5” inch sealed midrange). $25.30 each plus shipping and handling through Parts Express.

3. The you have GRS and Gold wood and Pyle speakers. All have sealed 5” inch midrange drivers.


I could buy a nice 5 inch midrange woofer and put it in a sealed container that Eminence has model number ISO5-5 at parts express for $14.99 each. I would stuff it with acoustic stuffing.

Here are some other suggestions or ideas? Dome midranges or full-range speaker drivers?

I will be playing a lot of old theatre radio and listening to some music and maybe tv shows through them but, not sure. 🤔. Pleased let me know your thoughts or suggestions on this topic. Speakers are over 50 years old and drivers are old and crackly sounding. I replaced the blown tweeters with cheap piezo tweeters and will go back to the horn ones with this new rebuild . Thanks for anyone’s input and help. Jeff

Any thoughts or comments on Wayne's linestage presented at BA 2018?

It looks like an economical high performance design with a couple of nice options (like a beefier output if needed)

I'm a terrible designer and a slow builder - I think we wound be interested in hearing if there are any experiences or opinions yet.

Thanks Wayne!

YouTube

I found myself with time on my hands and enough parts to build a subwoofer and a plate amp (based on The Bog Standard) so I figured "why not?". I also needed a filter, so I drew one up. It's probably pretty naive. Just a simple preamp/buffer and a second order Sallen Key filter. I want to be able to set the cutoff frequency, so I made one of the resistors in the Sallen Key-filter variable. This works in SPICE as well as on breadboard. But is this too naive? I'm also getting about 50-60 degrees phase shift at the cutoff frequency. Should I be worried about this? Ideas for improvement are appreciated!

Hi all,

After the release of the Bigbottle MC only phonostage (thread here: Bigbottle MC only Valve/JFET phonostage Group Buy - diyAudio) i was asked why there was no MM option by a few members. I didn't need MM so i hadn't considered it. Eventually i was approached by Andy who generously offered to redo the PCB design if we wanted to add in MM capabilities. Obviously i wasn't going to turn him down 😀
Alan redesigned the phonostage to offer MM & MC.

A few months has passed and we now have a few prototype PCB's here and rather than release them untested or as a work in progress like i did last time, we thought it would be a good idea to ask for volunteers/guinea pigs who would be willing to construct the phonostage and report back if there is any unexpected results. The idea being that when it is finalised, there will be less updates and a cleaner start to finish build process.

Obviously, you will need to have the ability to troubleshoot the PCB as it is very difficult trying to help people via phone or email. This is a lesson i learned from the first board. I'll do my best to help (I am only a "middle man" after all!) and Alan will too so you dont need to be an absolute expert but a bit of knowledge will be beneficial.

So, we have 3 PCB's available. All i ask is that it's built in the near future and that you report back any findings or measurements that need looking at.

If you are interested, please drop me a PM. Please remember, this is a not-for-profit project so all help is appreciated greatly.

I'll add a few pics of the PCB later today.

Design Phase - 35Hz Tapped Horn w/ Compression Chamber (Hog Scoop + Inverted Driver)

This project has been inspired by all the love for Hog Scoops... And the fair share of hate they get as well.

This will bee my first attempt at an 18" horn subwoofer.
Proposed plan is based on the well known "Hog Scoop",
a tried and tested free design hosted over on the freespeakerplans.com forum.

https://www.freespeakerplans.com/?view=article&id=31:hog-scoop

Drawn up nearly 20 years ago, this well proven classic has stood the test of time and is a very
clever piece of speaker box design, still to this day.
Credit for this creation must go to Stipe Ercegovic, more commonly known a Staiper, a well respected member on the Speakerplans Scoop subforum for a long time,
but he disappearred from there several years ago and doesn't seem to frequent these places anymore.

The Hog Scoop, technically an F1 hybrid of sorts, the offspring of two genetically similar species,
living a life somewhere between a tapped horn and a traditional back loaded "scoop".
A rear loaded horn with the bonus of the driver shooting into the horn path, or a tapped horn enclosure
equipped with a compression chamber.... Call it what you will, this quarter wave resonator is well capable of
hitting the low bass notes and producing high SPL when equipped with the right hardware.

So, I would like to run inverted drivers in a slightly tweaked version of this enclosure, something similar to the image attached to the end of this post.
These are the M4.18 subwoofers, made by MM-Acoustics in Europe, a Macedonian outfit headed by Marjan Milosevic, a regular poster and long time member over on SP.

My god, they look absolutely amazing, so business like.
This is the look I am going for.... They are absolutely badass indeed.

Anyway..... enough airy introductions, and down to business then !!

Hog Scoop Hornresp input parameters

First things first, I decided it would bee prudent to simulate a hog scoop with a driver in it's normal orientation first..... Cone side out.
This was to bee my baseline sim, a benchmark to work from before l went tweaking the original design.

And staight away I ran into problems.

For a start, the speakerplans.com forum isn't very active these days..... And a huge amount of information from back when it was is just lost.

Many externally hosted images are not there any more, there are many dead links, hosted plans, you name it, gone !!!
It didn't make my research easy but I did what I could with what I had.

That said, there were many helpful and informative threads to bee found amongst all the bickericking and the politics in the Scoop subforum.

So, lets discuss what was available to find on the net first.... Multiple posts regarding the Hog Scoop hornresp input parameters were scattered around the web....
And just not consistent.
I was hoping to pull some numbers out of a post or a sketch somewhere but straight off the bat, numbers and posts were conflicting.

Unfortunately, I found more than one set of digits, which only infuriated and confused me even more.

Here are the most posted (and reposted) HR Hog Scoop numbers, I beleive they orignally came from Staiper, and these ones were the most common to bee found online,
copy and pasted in at least 4 different places, so I am inclined to stick with the guy who originally penned the Hog Scoop design. He did create it after all.

Stipe Hog Scoop

S1 = 750
Con = 112.8
S2 = 1062
Con = 42
S3 = 1770
Con = 51
S4 = 2544
Con = 47
S5 = 5700
Vrc = 0
Lrc = 0
Fr = 0
Tal = 0
Vtc = 49456
Atc = 86

Re-posted by bitzo,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=214119&title=database-simulation#214119

toastyghost,
https://forum.speakerplans.com/forum_posts.asp?TID=16974&PID=727583&title=database-simulation#727583

Bee,
https://forum.speakerplans.com/forum_posts.asp?TID=72607&PID=828911&title=hog-scoop-drivers#828911

and salzburgsound system

The next set of input data numbers to bee found were these ones you see below.....
--------S1 = 750
Par = 0.10
S2 = 750
Par = 200.90
S3 = 1700
Par = 61.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Ap1 = 0
Lrc = 0
Lpt = 0
Vtc = 37060
Atc = 1453.10

Posted by Heathrow B Line
https://forum.speakerplans.com/foru...=901195&title=scoop-hr-reference-guide#901195

epa

Freddi

And one more, with newer and revised numbers, taken from a post by user "epa" from 2014.

S1 = 750
Par = 0.10
S2 = 750
Par = 187.90
S3 = 1700
Par = 52.00
S4 = 4740
Par = 12.10
S5 = 5700
Vrc = 0
Lrc = 0
Ap1 = 0
Lpt = 0
Vtc = 41091
Atc = 2210.00

Posted by epa

Other than these three sets of input parameters, I did find a few posts by Staiper himself, modeling the Hog Scoop as an exponential horn,
in quite a numerically sparce fashion I must add.... It would seem this stripped down form of modelling came from Rog Mogale himself.
i will link after the following
---------->
Staiper Exponential Hog

S1 = 750
S2 = 5700
L = 260 EXP
Vtc = 36000 (with driver)
Atc = 1000

https://forum.speakerplans.com/forum_posts.asp?TID=8887&PID=218876&title=hog-scoop#218876

Staiper Exponential Again....

S1 = 750
S2 = 5700
L = 257 EXP
Vtc = 37000
Atc = 9000

https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77534&title=tapped-horn-design#77534

And finally....... An attempt at simming a Hog Scoop by the man, Rog Mogale himself.

S1 = 750
S2 = 5700
L = 240 EXP
Vtc = 35000
Atc = 890

https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097

And here is a good thread full of interesting tit bits where Rog discusses his exponential scoop modelling methods with others.
https://forum.speakerplans.com/forum_posts.asp?TID=8329&PID=77097&title=tapped-horn-design#77097

A must read for anyone into this line of work.

Annd..... Time to take stock.

All my research and reading paid off, but unfortunately I still feel I do not have any concrete numbers for a Hog Scoop simulation binge.

So, I took some time out and drew up a scaled plan of the Hog, just enough to play with.
it gave me a much more definite idea of the direction I asm going in, speaker boxes ofthen quite literally build themselves as the project goes on.
Solutions are often just so obvious when you have the material object taking shape before your eyes.

And measurements can bee taken from the plan and scaled up to something that resembles real world numbers.
(Drawing attached)
And just to bee sure, I am going to get my hands on one side panel first, (18mm sheet board 986 x 950mm) and draw it out @ a life size scale on the floor.

Drivers for this design

I currently have 2 B&C 18TBX100 (4 ohm) belonging to a friend to use for the first 2 boxes and am debating which drivers to buy for the rest.

Quite likely B&C as well, I like the power handling (1500w) and price of the 18SW1OO.
When given the option, I usually buy 4 ohm versions of any driver when I can.
They can often bee had for the same price as their 8ohm equivalents but sometimes not. Sometimes they are just more hassle to obtain but I do make an effort to
use 4 ohm drivers when ever I can.
I am also open to other brands, I do know I need a certain type of driver to do well in these boxes and if one particular driver turns out to bee
especially suited to the task it will surely bee strongly considered.

So far, everything is going well.... The only other uncertainty I have right now is the design of the rear chamber.
I am not sure exactly how it will end up but I am confident the design (and build) process will answer it's own questions if and when they arise.
More on that in detail later.

Okay, I think I have written enough for now.... Any advice and criticism is warmly welcomed.
Please feel free to join me on my journey of discovery and don't bee shy to interject or comment if need bee.

Looking at the listed data sheets for D3a by , Philips, Telefunken and Siemens, all give short data for triode operation with grid voltage of +10Vdc. Yet they don't show that area on the curves. Just wondering if anyone knows what the original idea for application was there.

Thanks

To answer various instigations from forum members in the polemic of 'does THD..' I re-open this subject by submitting samples of audio recorded through the ADC of the Emu0404 to try to hear any differences in the various outputs of :
1. Dac of computer
2. Dac Ak4396 through ecc88 tube of Broskie unbalancer
3. Through Ak4396 + 6BL7 8 Watt tube amp.
4. Through Ak4396 + SS JLH modified amplifier
5. Through computer + SS JLH modified amplifier

Everything will be done at optimal levels for fairness and quality, (amps same power, dacs same output voltage, ADC same gain)

Actually all the chipset is on the sockets. Piggy is in very nice condition , collectible and even works. $250. This much becuase PDM100 is over $100 itself. I will post picture when I get home.

I use a pair of fostex pmo.4n speakers on my desk top.

They are individually powered and when I turn them on, they both emit a high pitch tone that slowly disappears as they warm up.

Any idea what’s happening with them?

Hi everyone.
I have a passive home studio system with a pair of older (well maintained) tannoy pbm 8, along with an equally well maintained pair of yamaha ns 10, and i’m trying to find the most appropriate upgrade on the tannoy pair.
Passive, 8’’ woofers, similar frequency response and not far more expensive. And of course i would prefer older used stuff. Not necessarily studio grade. Just different and maybe better than the pbm 8.
Any suggestions?
I guess older yamaha passives 8’’ must be pretty similar to the ns 10 (even if they are one of a kind in a way…).
Dynaudio passives are the first that come to mind. But i guess there are more, maybe cheaper and maybe better.

Thanks.

As naming suggests its going to be >1kw amp, design will be similar to the McIntosh 1.25kw amps but majority is going to be designed by myself from scratch.

Amplifier part:
It will be bridged monoblock = two separate amps in one chassis which feeds one common autotransformer with floating output. I have already successfully built this concept in my “MC502” and liked it very much.

Each amplifier is going to be fully balanced classic, nothing new or special. Input diff populated with ONsemi 2n5551/5401, Voltage amp stage uses fast KSA1381/KSC3503 with local compensation to tweak square as needed. As pre-drivers I want to try use Toshibas TTA/TTC004. As drivers classic and powerful MJE15032/33. No need to use anything extra fast here as everything is quite slowed down and compensated to match output transformers anyway. Drivers will feed 8 pairs of MJL1302/3281. Power supply voltage is going to be about 2x65Vdc and each amp will drive approx. 2,7R load.

Schematic:


Output stage transistors are split to two separate heatsinks, 4 pairs on each. PCBs are going to be interconnected with locking type IDC ribbon cable which connects main drive as well as temp protection sensor. Bias sensing is only on one PCB done by small to92 transistor sitting flat, directly in the middle of output transistor on top of the package. I plan to stick it there with thermal grease and whole assembly with PCB will force it to sit flat in there. This should provide quite quick and effective thermal sensing and bias tracking.

I have tweaked PCB layout and all the feedback sensing on amps PCBs the best I could to mix all the feedback from both split PCBs + output transformer, well the output terminals - so even the internal wiring is compensated 😉 Power traces are laid on PCB borders around for minimal effect on audio paths, with local low-esr blocking for each output transistor separately. Power and signal grounds are completely separate and going to be connected with separate conduit to main caps, the central ground.
Both PCBs of one amp are mirrored so all NPN/PNP output transistors are going to be on the same side when PCBs are oriented against each-other. This should ease up all the wiring. Below are a few pics of amp pcb:



(its still work in progress and don't have all the parts yet)

Audio inputs
are on small extra PCB which enables the use of balanced or unbalanced signal similar to mac amps. There is small switch for selecting the input used. As invertor I am planning to use OPA1611 as I feel that one is going to be most neutral of all. I want to make it as good as possible so I incorporated PP audio input caps, to fit them somewhere, they are going to be populated on the bottom side of the board. On this small board there is also small relay for audio mute, which shorts the inputs when amp turns on/off. There is also opto-isolated remote possibility to turn on/off the amp remotely.

This board also basically makes the common audio input ground of the amps (10k), the 100k input resistors directly on amp boards are basically just prevention for cable faulty.
Schematic:


PCB:

Here is my latest Tokin SIT amplifier. It is a DEFISIT amp (Depletion Enhancement Follower SIT) output stage based on Nelson's First Watt SIT-5 output stage. Diyers more knowledgeable than me picked apart what information Nelson provided in his SIT-5 owners' manual (https://www.diyaudio.com/community/threads/first-watt-sit5.418023/), and I rode on their coattails and came up with this version.

My build is only the output stage, and it incorporates the duo output capacitor arrangement which can be tweaked to adjust the amount of current amplification that the mosfet part of the DEFISIT push-pull output contributes to the total current amplification. This is a departure from the regular DEFISIT amplifier, where the SIT and mosfet both fully contribute to the total current amplification.

Here are a couple of LTSpice simulations. I did many simulations, but these two are what I based my design on. I chose -47VDC for one sim since I intended to build it using one of my existing amplifier chassis and power supply. I chose the -63VDC for the other since that is a reasonable voltage that will take advantage of the power capability of the THF-51S and still keep the power supply voltage reasonable for capacitor voltage and heat sink heat dissipation.

As shown in the simulation results (47VDC power supply and 2.0A Iq), the measured current through C4 connected to the SIT drain was 361mA peak, the measured current through C7 connected to the mosfet drain was 150mA, for a total of 511mA. As a check the current measured through the speaker, R8, was 509mA - close enough. So the contribution of the mosfet was 150mA/511mA = 29%.

I have not included the LTSpice screen shots of power output but the 8 Ohm power output was nearly 23W at 1% THD and 4 Ohm power output was nearly 40W at 1% THD.


63VDC PS 2A 8R 1Watt:



63VDC PS 2A AC signal current through C4, C7, and 8R Speaker:



47VDC PS 2A 8R 1Watt:



47VDC PS 2A AC signal current through C4, C7, and 8R Speaker:





As mentioned I decided to build the 47VDC version. The chassis and power supply is from my BAF2015 Amplifier - A SIT Mu Follower Revisited With Feedback (https://www.diyaudio.com/community/...t-mu-follower-revisited-with-feedback.408193/). The power supply is CLC, comprising 2x22mF - Hammond 156B - 2x22mF, and an Antek AS-3218 transformer per channel for full dual mono construction.

I put together a PCB design and sent it off to JLCPCB for fabrication. In addition to stuffing the PCB once I received it, I also changed the CLC filter from V+ supply to V- supply.



Initial power-up and subsequent Iq and SIT Vds adjustments went smoothly, and Iq and SIT Vds were stable.

Next up was testing with an 1kHz signal and distortion measurements. Unfortunately when powered up with an AC line powered 1kHz oscillator connected, the amp immediately blew the powerline fuse. So it was trouble shooting time. After checking the schematic and pcb, checking that the input capacitor was not faulty, and not finding any visible ground shorts with the meter, I was baffled.

I knew that the issue was mostly likely a grounding problem and that it only manifested itelf when an input device was connected to the amplifier. Luckily a thought came to me fairly quickly - when I changed the CLC filter from V+ to V- supply, I forgot to move the power supply connection to safety ground on the CLC filter board. The correction was made and success. Only one fuse was permanently damaged.

The dim bulb tester came in handy here as once the fuse blew, the dim bulb tester went in and I was able to probe around with power and not blow anything. In addition to using it during trouble shooting, I always use it for first power-up testing of power supplies during various stages of construction and first power-up testing of audio circuits.

As for the amplifier supply not shorting with no input device connected but shorting with an input device connected, I gave it some thought. The power supply was for V-, with V- from the supply connected as power to the amplifier circuit. V+ from the supply was connected to the amplifier circuit board as ground. The V- from the supply was ground in the previous amplifier but I forgot to change it so it was now incorrectly connected to chassis safety ground. With no input device connected to the amplifier circuit, the power to the amplifier board was floating. Although the V- was also connected to the chassis safety ground and to the powerline/IEC ground, there was no other direct connection to V+, so no short. The live from the powerline/IEC was connected to the transformer primary, which was isolated from the transformer secondary. Also the speaker and input jacks were isolated from the chassis. So with no complete direct connection of V- to V+, the current can only flow through the audio circuit. The chassis was connected to V- but there was no path for the current to flow from the chassis to power supply V+.

When the oscillator was connected to the amplifier input, the circuit was completed, current flowed, and the fuse blew. That was because the oscillator was AC powered and had a safety ground connection. So the oscillator line safety ground connected to the oscillator power supply ground, then connected to the oscillator signal ground, then connected to the amplifier signal ground, then connected to the amplifier V+. The oscillator safety ground is also connected to the amplifier safety ground through the line ground, and the amplifier safety ground is connected to amplifier V-. The net result was amplifier V+ and amplifier V- were connected together - a short circuit. There was a CL60 thermistor at the amplifier power supply ground connection. That would have limited the short circuit current: 47V/10R = 4.7A. Fuse was 2.5A slow blow.

I have swapped power supply polarity before but had always remembered to switch the safety ground connected, until this time.

So always be careful. Electricity can kill.

I got a preamp board and it works fine, but this one component (what exactly is it?), which is attached to a heat sink, gets very hot, while the other doesn't. Is this normal for this kind of device or should it be cooler? Pic attached. Thanks for any answers!

I am the owner of a pair of Magnepan Tympani 4a’s. At least 35 year old now, and still in great shape. Still I think upgrading the Filters is a good idea. I’m looking for detailed drawings or anything else that can make my choices easier.

Hello DIYAudio community,

Couple of years ago I’ve designed a DSP Class-D amplifier called Centure 21. It has got ADAU1452 DSP, TAS5548 as I2S->PWM modulator and 4 output channels, with 4 more available on the "PWM" header.

and photo of the prototype:



on the left there is Amanero header, which can be used for amanero module to have just USB 2 ch input, or my York interface. There was also header on the left side with S/PDIF and I2S which are connected to ADAU1452. The purpose is to connect daugter boards with different input interfaces: ADC, AES/EBU, TOSLINK etc. The module was used primarily for home audio.

After some discussion here on DIYaudio with @florentg (https://www.diyaudio.com/community/...-dsp-bluetooth-aux.376006/page-2#post-7719605) we meet in person played with the Centure 21 and discussed what we could do in the field of DSP amps, the specs and software and ways to build something better. Recently TI announced a new amplifier IC TAS6584 which basically combines I2S→PWM modulator and the output stage but also have some quite interesting features, like the H-Class power supply control.

So a new device was developed 🙂

Structure of Centure 24:



The structure of new version is quite similar to previous one: there is DC-DC for output stages, a DSP chip and MCU to control and monitor the system. The main difference is in more advanced diagnostic and monitoring of the sysem, thanks to TAS6584. Also since TAS6584 implement H-Class control together with the DC-DC, this fetature is also available and can be enabled/disabled via software. Here is demo from TI: https://www.ti.com/video/6287333584001



This time the module designed such that it can be also used as the plate amp: all the interfaces (S/PDIF, I2S, I2C) are routed to headers and supposed to be connected to interface board (which is not ready yet):



The amplifier has 4 channels which can be configured as 4xBTL, 2XBTL + PBTL or 2xPBTL. So it allows fleaxible configuration for multiway systems. The nominal output power would be around 200W for all channels combined, the peak power of course would be higher. Not all measurements are done, only up to 100W/channel.

There is also software development going on which is based on the York interface (thread on DIYaudio: https://www.diyaudio.com/community/...tichannel-input-output-interface-york.413504/)




Live monitor of Class-H operation:




Measurements, experiments with the H-Class control and config software features will be posted later.

I'm coming from playing music, then studying electronics and then sound design.
Along the way I was fortunate to meet an awesome dude who got me into diy audio after i heard his horn speakers.

Got some diy TL's and 3D printed Bill Waslo meh's with 12" bass port cabs. Also a pair of Genelecs 8030.

I'm hoping to upgrade my bass situation in the near future. 🙂

For sale 8 B.B PCM 1704 K comes from a DAC Audio G.D Ref.7.1
can be sold still on the board or unsoldered (hot air gun)
90 Euros each PCM 1704 K (reduced depending on the quantity, negotiable)

Hey friends, I'm really trying to download a pdf catalogue from hifiengine, but as you know new registrations are closed 🙁 does somebody with a valid account can help me to download this Dynaudio catalogue? Thanks a lot !

https://www.hifiengine.com/manual_library/dynaudio/diy-program.shtml

I have 4 sets of PCBs left over from my 6xLM3886 Parallel BTL amplifier project. Due to the minimum order quantity (5 pairs), I only used one set for my build, so the remaining 4 sets are now available.

For full project details and discussion, please refer to the forum thread:
👉 A New EC-Composite LM3886 Amp


PCB Specs:

4-layer board

1 oz copper on all layers

ENIG finish (1μm gold)

Dimensions: 220mm x 55mm

Designed specifically for the 6xLM3886 Parallel BTL configuration

Price:
$40 USD per set (includes 2 PCBs)+Shipping

Shipping via tracked Canada Post package
(Payment via PayPal – Friends & Family option)

Please PM me if you are interested.

I recently acquired a set of Paradigm 11se Mk-1s from a friends dad. I've read a lot of great things about them but I think they suck. Of course everyone's opinion is going to be different but I think something is wrong with them but I don't know what. Let me explain....

These Paradigms are the ones with the Vifa DT19 tweeter, the Vifa D75 dome mid (the original gray dome) and the milky clear plastic 10" woofer (I'm assuming an Energy driver). Now I know these are often considered forward sounding, and I agree, but in every other respect they are worse then every other speaker I have. The largest of the issues is the dull, lifeless, anemic bass. And yes, they very likely have the original crossovers. I know these are early Paradigms, but a custom spec'd woofer in this big box, with three big ports? Even Chris Roemer's Nano Neo MT speakers have deeper and more powerful bass. [It sounds like I am talking about blown woofers maybe, but they do work and there is no distortion...]

In direct comparison to Energy Pro22 Reference Connoisseurs, the Energy's have a wider, taller, deeper sound stage, tighter imaging, and higher resolution. The 7" pro22 woofers have considerably more and deeper bass, with much more life and texture. My specific Pro22s have Solen caps in the crossover but I bet they are 15-20 years old.

The same impressions apply to my ADC 303x speakers (with brand new crossovers), though not as deep in the bass as the Pro22s. My newer speakers are significantly better then the Paradigm, but I just wanted to compare speakers from the same era. I've used tube and solidstate preamps and amps, even a tube/classD hybrid amp....same impressions. The Paradigms simply do not match up to any other speaker I own.

Normally I would just say they are not what I am looking for but everything I read on line in nearly every form suggests they should be at least equal if not better than the Reference Connoissurs.

So what do you think? Could the Paradigms be ranking so low just from the old crossover, or do you think they honestly are worse than the Pro22s and ADC303x's (with modern crossover parts)? Something else wrong with them?

[for reference, I appreciate a darker speaker with great soundstaging higher then tonality or analytical qualities. I listen to classic rock/modern rock/pop/classical at mid 90s db's]

Finally got the chance to see it. Thoroughly enjoyed it. Go see it folks.

After Sean Bakers “Red Rocket (2021)” again a modern fairytale at the wrong side of society. Recommended!

https://m.imdb.com/title/tt28607951/

This is the Millett Hybrid amp but with Edcor OPTs. You can read about it on his site.
The chassis is steel and rift sawn Sapele.
I am asking $450 (plus shipping), which is basically the cost of parts. I would prefer to sell locally, if possible but I am located in Santa Fe New Mexico, so that might not work out. If you are interested but would require shipping in the US, feel free to message me.

Cheers,

My name is Michael and I have been visiting this forum sometimes before an really enjoyed reading about all your cool projects.

HiFi is my favorite hobby.

Two years ago I startet doing some projects on my own instead of just fixing vintage hifi stuff…mainly from the 70s and 80s.

Right now I am looking for a good solution to drive my vintage Grundig active speakers…I will post about that in the existing thread.

Thanks for letting me take part in this great community!

Greetings

In the last few days off, I have been somewhat confused and have tried to collect enough reasonable data for a possible replacement circuit using the usual home remedies. I don't know whether I succeeded or whether I was able to develop a common thread; the more diagrams one plot, the more confused the scenario becomes. I deliberately left out the interesting mechanical side, because how can one approach it reasonably well with home remedies? Of course one can think about the elastic side between the cantilever and tip and the plastic disk, but on average we always come to a conclusion, reso fo is always less than 35kHz and the cutoff fc moves from 61kHz to 32kHz ... outside to inside.

Perhaps we can develop a test procedure, a common thread, together at this point.

What is the difference in the end between say using a DN2540 style CCS at the anode vs a LM317 CCS at the cathode? Isn't the end-game objective the same to fix the DC current? Does the anode CCS also provide a higher impedance load benefit, whereby the cathode CCS would only fix the current but not ease the load? What if my driver stage currently uses an interstage transformer load, could adding a CCS above anode choke really improve things beyond a choke alone? Basically if you had a driver stage that had a interstage anode and cathode resistor. And you wanted to add a CCS, would you add it at the cathode or anode?

I like restoring turntables, I find it a bit meditative compared to my daily grind. I like building new plinths and such but always make sure I can restore it back to its original build. Making a new plinth is easy for some players like my Thorens TD-150, just a simple wooden box (ash in this case).



Others has proven more challenging like my Technics SL-23.



My latest object is a Thorens TD-115 MkII. I bought it fairly cheap at an online auction and it looked quite alright when I picked it up. The previous owner talked a bit about having problems to get it running at 45 rpm but i didn't pay too much attention. I bought it to have something to work on but it would turn out to be much worse than I initially anticipated but more about that later. I was not planning on making a new plinth for this turntable. The original plinth in a quite complex thing in plastics with a very special dust-cover design. I just wanted to restore it but why the TD-115 MkII? Well it is quite interesting functionality-wise and got some great highlights technology-wise.



You either love or hate the original design. I like the sliding buttons like the ones on the TD-125 but I don't like the overall plastic feel. I like support for 78 rpm, the suspension and the option of fully manual or semi automatic operation (with a friction free velocity sensing electronic shut-off, stopping the motor and raising the tonearm). I like the motor, the speed control electronics with load correction, fairly low wow/flutter and rumble figures.

But my turntable, after closer inspection, turned out to be in quite sad condition. One of the holding tabs on the dust-cover was nicked and several plastic pieces on the raising mechanism was broke. Something was seriously wrong with the electronics and the platter bearing was probably shot. One of the buttons on the control panel was bust because someone probably tried to clean it with acetone (what looks like brushed aluminum is just paint).

But the tone arm seemed OK and all the electromechanical parts under the control-panel seemed complete and functional so I started to play with the idea of reusing as much of the original parts as possible and make a new plinth and dust-cover. I was not too worried about the plinth but I wanted to keep the dust-cover design (being able to put the turntable up against a wall) and that was quite a challenge. It took me quite some time to come up with a plan of attack and I would take it step by step...

This thread is me documenting this build in case anyone want to try something similar. A word of warning, don't even try if you value your time more than tinkering in the shop. I really enjoy this kind of work but this build took me close to six month to complete (approximately around 100 hours of work).

I offer here for sale the F5 V3 amplifier boards, completed with good quality parts and orig. Toshiba jfets. I would like 120€, plus shiping, payment by paypall.

Dear gentleman I have FS a stereo set of the Sapphire heamphone amplifier ver.4.1t. Fully build and tested, because I dont listen to headphones... it is a waste not to be used...

70€ + shipping + pp.

I have for sale 2 beautifull power transformes for tube amps.
Specifications:
360-0-360 200mA
5V 2A
5,5V 3A
80V 50mA
3.15-0-3.15 v 1A

Transformers are from a opera-consonance 300B. Working perfectly, without any his and noise.

Lets say 120EUR for the 2.

I have for sale Kubelic nos dac kit 2 pcs. Only asembled.

100eur for both +paypall fee.

So I've never learned how to layout a PCB. I figured I'd throw $15 at fiverr to see if someone would layout this transformer pcb for me with wire to board terminals exposing the taps and giving mounting holes. Attached is what I got back dimensions are 108 mm x 59.9 mm

I'm wanting to shrink it to say 83 mm x 58 mm I just don't know how.

The transformer is a triad FS16-400-C2
Datasheet: http://catalog.triadmagnetics.com/Asset/FS16-400-C2.pdf

The terminal blocks are Phoenix Contact 1706756

Can someone take a look at the gerbers and give me some pointers on how to do it, and if they would make any improvements?

Hello

Looking for good cabinet plans for Markaudio Pluvia 7HD

By googling i did find this one https://frugal-phile.com/boxlib/pensils/PensilP7HD-260520.pdf but its not on offical frugal phile site you can only find it by direct link. is it still ok for PLUVIA7HD.2 GEN ?

Also considering plans from:

https://sites.google.com/view/low-end-diy-loudspeaker/diy-tqwtml-voigt-pipe-with-damp-duct
https://sites.google.com/view/low-end-diy-loudspeaker/diy-tapered-wave-tube-with-damp-duct-twtd

Does anyone know any other plans for Pluvia7HD?

Thanks

Not going ahead with these projects, so looking to sell the following:

1. Aleph Jzm kit. Bought directly from the diyAudio store. Looking for 135AUD (~85USD) + shipping.

2. Reflektor D full kit with PCB. Looking for 80AUD (~50USD) + shipping.

3. 2x SLB PSU PCBs. Looking for 30AUD each (~20USD) + shipping

The content of this thread is my personal opinion and does not represent performance based on objective metrics.


Information about symphonic-mpd, a CRAFTED LINUX for Raspberry Pi4.

It has been developed to target audiophile who want high quality music playback on I2S output.

Official Forum
symphonic-mpd

If you are interested, please ask your questions in this thread.

In order to use the SD images of this distribution, you need to join the official forum.
If you would like to join, please email me below with your handle name.

symphonic.mpd@gmail.com
kubotayo@jcom.home.ne.jp
mark.create@gmail.com

Hi everyone!

It's been almost two years since I last built a speaker, and I'm getting the urge again.

[TLDR:
A more compact floorstander using an SB Acoustics SB15SFCR39 for bass in a vented enclosure, extending further down to the early 20hz with boundary/room loading. The B&C 5CXN44 in a sealed enclosure for mid and high.]

My current setup is really good (here), but a few aspects have me considering a change:

Size: The speakers are quite large.
Low-end Limitation: They only reach down to 35hz with boundary loading.
Horizontal Coverage: It's not as wide as I'd like.
Practicality: The horn on top is a bit of a concern, especially with baby GG² about to start walking.



As you can see below the measured 'anechoic' response yields quite a bit more low-end extension when in the listening position. I thought this would be fine but there has been the odd movie or song that lacks a little in the rumble department. Boundary loading really is my friend here (more on that later).




Shortly after building these I added Dirac and that improved things a lot over my manual room correction (manual not shown).



When I made my workshop speakers (here) I really enjoyed the sound of the B&C 5CXN44 coaxial drivers and found that they gave quite a nice wide image even when I am at the end of the sofa. I think this is because of the diffraction and tuning the response to work best slightly off axis due to the choppy response a 0 degrees.



SO...

An idea I have been chucking around in my head for a couple of weeks is this:

A more compact floorstander using an SB Acoustics SB15SFCR39 for bass in a vented enclosure, extending further down to the early 20hz with boundary/room loading. For mid and high, the B&C 5CXN44 in a sealed enclosure. Both drivers would share the floorstanding unit, reducing both physical and perceived space.

SB15SFCR39 ≈ 26L / 35hz vented
5CXN44 ≈ 4L sealed

I am totally up for other drivers but I don't want to go beyond 200mm wide baffle and I'm not too keen on a side mounted woofer owing to little fingers.

I have this cheap little class AB amplifier. I am getting a hiss through any speaker I connect it to. Both channels. I'm thinking bad transformer but I will run through my troubleshooting steps. It is HIGHLY likely it is a just a bad design and there is noise between signal and power on these boards, however, many have used this amplifier without this issue. BOTH channels hiss.

I do not have the schematic

Findings:

1. When it is whole and you power it up you can hear the power supply transformer hum. The soft start relays kick on once the caps are charged and then you start to hear the hiss. The sound from the transformer isn't that different from the sound through the speakers which is why this is suspect #1. The transformer makes no noise unless it is hooked up to one of the boards. I know class AB is always on and pulling some power even at rest so this makes sense.
2. The hiss seems less noisy with the 120V input ground disconnected which is strange. If you scratch the 120V input ground on the chassis you can hear the scratching come through the speakers. This seems to point to a grounding issue in the design. This ground only goes to the chassis. This is suspect #2
3. There is a 3 pin volume pot for each channel. If I spin the volume pot with my head up to the speaker I can hear the sound of the pot turning coming through the speaker. I do not know how to bypass a 3 lead volume pot. I have disconnected the pot from the boards which seems to default it to the lowest volume level. The hiss is still present.

Things I have tried:

1. Disconnecting the volume pot - no difference
2. Separating the boards and moving them far from the transformer - no difference
3. Attaching the incoming 120V ground straight to the chassis and then to the building's conduit. I know the buildings conduit is a good ground as we have had to test this for other things we have built in the shop.
4. I soaked the transformer in polyurethane. I was hoping to quiet the actual mechanical noise of the transfomer. This also did not help.
5. I took a pencil and started tapping all of the components while it was powered and I could hear the hiss. Touching the components had zero effect on the hiss. I was hoping it might have been a badly seated/soldered component but that does not seem to be the case.

I open to try any suggestions at all. I have hooked this up in both my shop and my house and I get the same noise. I don't think its DC on the AC line since I have another class A amplifier that uses a toroidal transformer and I hear zero hiss coming out of that one. That one is about half the power but it has abosolutely no hiss at all.

The transformer is outputting 12v as well as two 35V leads to the board. Right now I am thinking its the transformer. Could be a bad batch of these cheap filter caps. I really do not have enough experience with class AB amplifiers to give any type of informed guess. Thoughts?

So, the kit of the AtiRi has been bought and I am thinking of pumping it up and make a Kawero Classic clone (kind of) out of it.
But I need your help regarding the bass segment.
My plan is simple, take the two way AtiRi (15Liter) and put on a 40Liter bass reflex cabinet. untill now same as Kawero.
The woofer I will use for the 40Liter is the 10inch Faitalpro RS350. it will be driven by Hypex Fa501.

Now, I really really want to nail this bass, clean accurate, powerful.
So the following ideas are:
1. 40liter-bass reflex with one RS350 10inch driver
2. 40liter- closed cabinet with one RS350 10 inch driver -infinite baffle
3. 40liter- Closed cabinet with Two!! RS350 10 inch driver

I know its more about opinions and everything is a compromise but it would be great to hear your preferences.

Thanks!

Now it is new plans on Markaudios site.
I dont know were we can buy that driver.
Maybe it will come later.

https://www.markaudio.com/online_shop/11-cm/maop-11ms/

Electronic Schema Power Amplifier LJM L20SE

Electronic schema and analysis

Schema: Amplif_L20SE.pdf - Google Drive

Project: Amplif_L20SE.ms14 - Google Drive

I am not marketing this product and I am not the author of the project. I did the schematic circuit for analyzing and sharing information.