I hand to cut those ovals using my DIY flattening jig 🙁. And then spend several hours cleaning up the burn marks (cherry). But the front panel is finally ready to glue to the side panels. I still need to make 23 more tweeter assemblies. Fortunately, the 20-channel amp is done, although there is lots of code involved, which by definition is never done 🙂

Based on these pics of my MK-121-2A, can anyone tell me if this is unmodified? Also, looking at the 3rd pic with the strip with options to connect to red, orange, and yellow wires, what are these options for? It is currently wired to the middle/orange tap.

Just checking the interest for a group buy of my single channel regulators, SSR01 (positive output voltage) and SSR02 (negative output voltage).

The design has the following feature:

• 4-layer pcb with 70 um (2 oz.) copper.
• Power traces 140 um!
• Gold pads.
• Extremely low noise.
• Extremely low output impedance in the audioband.
• Small size.
• Easy to change voltage, also to negative voltage but this particular design (pcb) requires two different pcb's, one for positive voltages and one for negative.
• Well-known and well-tested in serious and demanding applications.
• Option for TO92 or SOT23 transistors for the small signal transistors.
• Option for DIL08 or SO08 opamp.
• LM431 (and similar) reference or devices like LM329. The pcb has a universal footprint.
• Trimming options for both the reference and the feedback. Room for extra resistors and trimpots.
• One output with sense inputs.
• Option for using higher voltage than the max supply voltage for the opamp.

I will put up a google doc list for signing up interest. I will also come back with prices and conditions. The price will be good, I can assure you.

I just picked up 4 of these dual woofer 3 way speakers. They were probably custom built in the 1970, they big and heavy. I've have been fixing the crossovers that fell apart over time.

The midrange and tweeters appear to be good quality and are mounted on top with speaker cloth covering the front and sides. The rear ported cabinets are approximal 3.3 cf with 2 10" woofers that I guess are Eminence. The internals have some unique braces and a quasi labyrinth design.

Any suggestions on how to get a better response curve?

Hello, I am like many people and looking for a way to retain my original radio system, specifically the way it looks. I have already looked into a lot of different things such as hideaway systems etc.

I want the OEM radio to control the sound system so after doing some basic math I have found one way that stands out to me, and would like feedback over feasibility and difficulty

Purchase a preexisting radio and put the components inside of my current OEM unit, then make the OEM buttons control the new radio/stereo.

The interface/faceplate on many new single din radios are detachable, which would allow me to solder either through that specific port or to the individual locations on the board.

The front of the radio I want to keep is from a 1996 F150 (16 buttons and a small display).

Would it be easier to use individual buttons, attempt to make a PCB or solder board, try to break down the current board and use it for the buttons? Also, is there something else that I am completely overlooking? Something easier?

I have a basic electrical background and understand a lot of the basic context that would be used here. Obviously a lot of it will be a learning opportunity as well, which I am excited for. So any help/guidance is appreciated.

Hello and a good day to all, I am fairly new to crossover designs, I am trying to make a passive 3rd order butterworth crossovernfor my subwoofer, I have the following components:
L1 2.85mH ESR 0.15ohm ferrite bell core
C1 3 x 220uf bipolar caps for the shunt
L2 1.18mH ESR 0.2ohm same ferrite bell core inductor
The woofer has a Re of about 3.8ohms
I am trying to get close to about 150hz cutoff,
I did some calculations and I should be close to this value with the given components, but I am new to crossovers and maybe my calculations are wrong
Could anybody help me if these values will result in close to 150hz?
I can alter the capacitor to increase the value if needed, but I don't have larger value inductor

Thank you all for your time and help with this

Criss

I am looking to invest in some test lab equipment to enable accurate testing of circuits I build or modify. Ultimately I would like to be in a position a year from now to be able to diagnose audio amplifiers, tube and solid state and fix them.
Admittedly apart from college I have no electronic testing experience other than validation of test reports frequency plots etc.
So to summarise:
1.) If you could advise on educational resources that I could learn the theory from.
2.) Starting with an initial budget of say £2k, equipment that you would invest in and why.
3.) Initially I want to do this as a hobby but ultimately as a evening job diagnosing/ fixing audio equipment- in today's climate specifically in the UK is there much scope for this (no pun intended), or are the margins that small it's not viable as anything other than a hobby?

Your thoughts, feedback, advice, guidance are welcome.

Thanks

Paul

No issues other then a few scratches on top from rack mounting. 300 USD

Hi
my name is Rainer. I am following diya for more than 10 years but wasn't active to avoid matter of conflicts. For the last 30 years I was in various positions in the audio industry - mainly with Marantz. This came to an end and now as a hobby want to participate in some interesting projects...

Hi,
I'm looking for a 2.0 class D board to use with a linear 34V 3.5A PSU. I don't need high wattage, maybe 40-50 wpc. I've already built several TPA3116 based amps so I want to try different and more modern chip. Reading through the forums, people seem to suggest TPA325X boards over TDA7498E. However, it seems like only TPA3255 are widely available (in my country, the ZK3002 boards are easy to get). TPA3251, TPA3221 or even MA12070 are rare and more expensive. They are often has features I don't need, such as, bluetooth, tone controls or sub channel.

I felt that using the 3255 with my PSU will waste the opportunity. So, is there any option or source of lower power board available? I'd preferred the 3250/3251 for slightly more efficient and better stats.

Thanks,
AP

ive got a Audio Research LS1 that has some hissing on the right channel that goes away once its running for a while, i suspect one of the old fet's going bad.
unfourtainly they are painted over and just marked FET, White Orange in the SM



Does anyone know what model they are?


Also whats going on here? are they just using them as capacitors?


i may also get a new 6922 tube to see if its the problem

A short question. The goal is to be crossed at around 3-3.5kHz with about electrically 12dB/octave slope, acoustically 24dB/octave is preferable if possible.

Which tweeter is more advanced in technology?
A. 19 mm. woven soft dome with ferrofluid cooling
B. 25 mm. woven soft dome with air vent cooling

There is a huge difference in the price of loudspeakers. Some are a few dollars others are thousands. What are the factors that make a speaker driver expensive? If it was low distortion wouldn’t the distortion figures be advertised? Some is of course proprietary materials and expensive processes like MAOP or diamond coatings where the process often destroys more membranes and diaphrams than are used. There is also market demand, which I don’t think is a big deal for most hi-fi speakers. In the example below one is a matched pair, obviously there is a cost to match drivers to some tolerance, but is it worth $800?

What is the cost driver to produce good power handling, flat frequency response, low distortion, etc?

Here’s a somewhat absurd example from PE:
The least expensive full sized dome tweeter.
$6.98, GRS 1TD1-8 1" Dome Tweeter 8 Ohm ($13.96 for an unmatched pair)


A similar, and the most expensive, dome tweeter.
$808/pair, Morel TSCT1044 Supreme 1" Silk Dome Neodymium Tweeters - Matched Pair

Hello diyAudio forum,
Long time lurker here.
I'm from the Bay Area California and love audio equipment.
My recent diy project includes AMB M3 and AMB B22 headphone amp.

I'd love to build my own Power amp whenever I have a chance.

Do you have 10 TTA004B tp sell to me?

About 2-3 weeks ago I got inspired by ncbluetj's BASH build which uses 4-15" !! https://www.diyaudio.com/community/threads/the-b-a-s-h.391536/page-6#post-7190481

Decided to see if I could retrofit a pair of 18" to an old synergy prototype....looked like it could work, providing a box could be built to wrap it.
The old proto is a 75x60 build that uses two 12"s, four 4"s, and a coax CD.




I'm like yeah, I can build a box around it, but it's going to be one heavy sucker. I'll need to build it on site, in its final resting place.
Decided I wanted to build it on a stand to match the height of other synergies sitting on tall subs. Used a vented sub box emptied and turned point up for the base.....(which already had coaster wheels, yay)



Built the box pieces and painted them. Time to assemble.

First thing was to mount the 12"s and seal them up the way the proto was designed.


So I can start putting it together on the stand.


Ann then add the rest of the drivers.


And then add the box.


Finish the wiring and seal her up...


Done. Assembly went nicely....took about 4 hours yesterday......happy camper 🙂

I believe this forum doesn't have a thread dedicated to Double Bass Array (DBA), so I'm creating one.

Wikipedia article about DBA :
https://en.wikipedia.org/wiki/Double_bass_array

(Images below are taken from the Wiki article)

To create a DBA we must set up an array of at least four loudspeakers on the front wall, and a similar one on the rear wall. The rear array must play in reverse phase to actively absorb the plane wave from the front wall.



A simple way to understand what a DBA does can be described like this:

- The front array creates a plane wave which should cancel standing waves in the height- and width plane of the room (up to a certain frequency)


- The rear array shall actively absorb standing waves in the longitudinal plane


The result of this is that no standing waves should be exited, and you get a frequency response that is completely flat, and a decay without resonances. In theory at least. With some tweaking, it's possible in practice as well.

There are requirements and limitations of course:

• The room should be rectangular with a flat ceiling (relatively easy to accomplish)
• The room should have very stiff surfaces. Concrete is good. Japanese paper walls are not.
• Apart from the loudspeaker arrays, the room should ideally be empty. Any objects disturbing the wave fronts will alter the result.
• Digital delay and EQ is required
• Measurements during setup is required

My own room doesn't meet any of these requirements. Even so, I was able to create this result with a lot of tweaking. The decay is very short down to about 30 Hz, where the neighboring room starts to contribute to the decay we see on the measurements here.

Getting a new laptop today......

It's known how to match FETs due to generosity of The One and Only. By the luck I've got some SITs and would of liked have them matched within reason. I can't make or borrow full blown curve tracer but I can plot a curve or two per device. What should I look for?|

I am proud to announce the release of Rev 3.0 of my award winning PecanPi® product line.
.

The PecanPi Streamer is a networked music player with build-in DAC and headphone amplifier.
The PecanPi DAC is high-performance DAC for the RaspberryPi and Tinker Board, this is for DIYer and tinkers.

With Rev 3.0 the big change is the availability of an S/PDIF input.
The S/PDIF input has an automatic switch over that takes audio from the S/PDIF connection when there is a valid signal. When no valid signal is available on the S/PDIF interface the device defaults back to taking streaming data.
With Rev 3.0 the linear regulator have also been upgraded to use lower noise parts.

The audio performance remains the same as with previous versions. Below I retook some of the measurements using S/PDIF input.


Additional Details can be found on my website here:
www.orchardaudio.com

Pair of good Thel Germany regs to up of 10A current.One negative and one positive.Taken out of functional power amp.No aditional check or mesurments.Sold as is!Price for bouth 50 euro plus shipping.The 4 black 10000uf nichicon caps are not included!!!

Looking for the rules on what defines a true subwoofer. Running many sims for LF drivers in WinISD has been a bit of an eye-opener on just how difficult it is to work models in the sub 30Hz region

Searching for guidelines on the internet re subwoofer definitions and requirements seems like those in the know cant agree amongst themselves. Some say a 3" .1 section from a PC multimedia 2.1 is a subwoofer, while on the opposite end it seems like there might be some consensus around 16Hz and some around 20Hz as the lower end extension to aspire towards

That's regarding frequency coverage. As for SPL requirements. This is more difficult to jot down as most will look at this from their personal requirements

After examining hints and efforts on what knowledgeable types seem to have been involved in, it seems to me that 16Hz is a good-looking number for F0 for a true subwoofer to support background music and effects with cinema for both realism and mood creation

Does this background music carry low bass, or is that mostly in the effects? I don't know, but something to study in the near future. When it comes to non cinema music, the bandwidth covered by the 5-string bass is plenty for me to wallow in bliss, so I suppose that covering cinema well would mean a well covered and full music experience. As mentioned, a good performance with a 5-stirng is plenty to make me happy and well borne out with the fact that one of the smallest THX rated unit, the cheap and cheerful Logitech z623 'sub' has historically been plenty for me with both output and low end

So can anyone set a bar?. What makes for true subwoofer?. I think covering the following would set one bar

(Note, most systems have a volume or Eq of some sort to bring things down to comfortable and acceptable)

A 16Hz F0 with 85dB attained band wide and with a 20dB reserve headroom from F0 to 300Hz can't help but ensure that the music is well covered and most satellite to floor standers well covered. Group delay under 40, but not sure about phase (what would be a good margin here). Some of this is borrowed from THX. And I suppose that rating attained at listening position would determine overall LF system size for the use with the gamers used as one example of use

Music is a tool used in games just like as in cinema. Let's use this gamer example to see how this translates at a listening position of 1m to see if I have my head wrapped around this correctly. In theory, if the subwoofer uses 1w to produce that 85dB at 16Hz at 1m, it would need 100w of headroom in reserve to create 105dB at that same 16Hz and this power requirement would escalate as listening distance increases (what is the correct calculation here?)

Would this be a good definition for a true subwoofer?

I'd had this Sharp cassette deck for fifty-two years, it's always played well, I put this video of it on YouTube.

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But lately I'd noticed a bit of noise from the left-hand channel when I turn it on. I hardly ever play it, but It's "there" if I want to. I like all my stuff to be working. But it's not worth having it repaired.

But I had a stroke of luck, I found this listed on eBay. Now for me, the "deal breaker," was the connections. It used din plugs on the lead like the other, I wouldn't have considered it if it didn't. The vendor said it was working, but hadn't tested it. That always throws up "red flags," but I decided if I bought it and it didn't work, it would be going back.

It's a Sharp RT-2500 Full auto-stop, auto Cr O2 plus Dolby.

What really impressed me was the condition in the vendor's photos. Not a mark on the cabinet, but although the black plastic had faded with age a bit, the lettering on the "POWER" and "EJECT" buttons were still clearly visible. If the lettering had worn, it would suggest to me a lot of use.





Anyway, I put in a bid and won. It arrived, extremely well packed. I checked it out and there was a lot of distortion on one channel. But a good clean of the heads with switch cleaner on a cotton bud cleared that problem.
The fast forward/return "didn't." It's usually a stretched belt. I had a spare set for the 442 which had a similar mechanism, so another fault cured.
Then gave the rest a good clean and it was good to go.



All the lights work.



It's only "mid range" but will do for me.

Well worth the £38 I paid for it. Which was half what I paid for the 442 in 1972.

Sounds OK.

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"Little Susanna Hoffs," the Bangles lead singer, was 65 earlier this year.

Doesn't time fly?

For sale second pair of Mundorf Supreme Silver Gold caps.
2 x 3,0 uf
2 x 0,82 uf
Used but in verry good condition.
Price 150 eu.Payment thru paypal.

Akai AP-L45- Help Lift?



Vintage tangential reading turntable, this is a masterpiece of Japanese engineering of the not indifferent weight of 11 kg.

I found it on the net recovered from a market and actually a little badly reduced in aesthetics, the electronics in itself seems to work everything but a small problem that I have to solve and that of the embrace that does not work, clearly compromising the correct operation of everything.

I therefore ask if someone already had to deal with this turntable with similar problems and how he solved it thanks Giampietro Italia Treviso

Hi,

I’m using a few different free software packages to use my PC as oscilloscope and spectrum analyzer, like Visual Analyzer (2024 version) and SoundCard Scope (V1.47). My PC uses W10 64-bit and a Steinberg UR242 external USB sound adapter. Input is for example from a low distortion 1 kHz. generator (Victor).

This works quite good in general with high dynamic range and low noise. Synchonization is fine too.

But sometimes the waveform (scope and spectrum) shifts a bit up and down, every few seconds a little bit. The software itself is stable of course. Mains voltage is stable too. All drivers are set to latest, firmware of the UR242 as well.

What can cause the waveform to go up and down a little bit in it’s window?

Regards, Gerrit

Hi there, i was inspired by Nola brios since i have two TG9 4 ohm, and i came out with this.

With my limited understanding, it seems the phase shift an aperiodic TL provides helps create a cancelation over a wide band.

In this case, the TL is tuned so there is a 360° phase difference at approx 650 Hz, and below that, until port tuning freq (200 Hz), i get a nice rear wave cancelation. This was choosed as an 3.5 inch driver is expected to abandom omni pattern arround there. For some reason, the OB makes for a better cancelation (in vituixcad), if its inverted, as prob brios are, according to some measurments in the brio thread.

Vituixcad shows awesome cancelation, but little arround TL tuning f, AKABAK shows the opposite.

Some sim images to show what i'm talking about...

The akabak sim is for generic speaker, no LEM data inserted as of now. TL was simed using Leonard audio and then translated to the other programs.
Now that both programs are showing the effect i'm after, i'll make some more iterations on akabak, and i'm gonna build it soon-

recomendations welcomed! Best regards!



This one is an imposible thing, as port distance from front baffle is about double of the TL, but it shows the effect real nice. I also ended up making distance between drivers 220 mm as 364 mm seemed like too much visually. Also, it makes the dip at 8Khz way more benign. The idea is that some day far from now, some supertweeter will lay there.

(forget the cap its not doing anything) (i will waste some power to make the load 4 ohm)
I bet this speakers from project10 are pretty directional too: https://www.diyaudio.com/community/threads/aperiodic-loading-to-lower-qt.162130/

As a new Magnepans 1.7i owner, I’m in the break-in period. Really working that mylar membrane requires power, meaning loud listening. I can tolerate loud music only for a short period. So, I decided to push membranes with a very low frequency signal, where dipole baffle is acoustically in short circuit (+ human hearing is insensitive) and doesn’t produce any sound, even at high power. Using signal generator at 1 to 5 Hz, loudspeakers are pushed with continuous power. I can clearly see mylar membrane excursion.

My question to experienced owners is whether there is anything bad in that method. I’m using only 25 Wrms, but that is 10 times more than I need on average for listening. It should speed up break-in for low frequencies, compared to music listening.

Already member for a while and interested in building the Firstwatt clones. Already built the Aleph J and recently build a M2x with different daughter boards.
Before that i build the P101 from ESP and several Neurochrome modulus-86 power amplifiers.
Regards,
Ton de Kleer

Hello, I am working on a project based on SA9227. He needs for his company to sign an NDA agreement. Unfortunately, for several months without success because I can't get a deal with them. I would appreciate any guidance.

USA. 48 yrs old. Married to a red head some 13 years now. Drive a little Honda. Construction worker, instant coffee lover and a sense of humor few understand. I like things that are different than what everyone else does, so like when it comes to car audio, I like things that are unusual and different. Where everyone else runs to the custom huge ported boxes with expensive brand subs, I'll buy like a Pioneer wx-7da and use tactile transducers mounted under the seats or use my Maxxbass 103 processor to get more out of some 8 inch underseat sub. I just never cared for large, heavy boxes nor want to annoy others with being loud anyway. I can also ramble on and on and chew the fat with the best of old men. You wanna hear someone talk? I'm your guy, I'll take you on adventures through story telling without a care in the world. Curious about that scar on my knee?...well let me steal 2 hours of your life telling you all about it. Sports?...well I know nothing about sports but I can brag about my time with a bisexual college cheerleader and that's close enough right? Meanwhile I'll try to sell you some of the junk I have in my garage which looks like an early 2000's version of an abandoned Best Buy storage room. But wait there's more. I have car audio output problems which I hope to make a post about soon because, well it sucks and nothing about car audio is cheap even if you buy cheap, it's not really cheap. Like how in the world can hundreds of car audio manufacturers stay in business competing with each other? How does a brand like say Savard or Incrimnator Audio stay in business when there's like a dozen other companies like them on top of dozens of mainstream, popular brands like Kicker on top of all the in between brands and cheap Boss audio type brands in a world where most people don't usually do anything with their cars OEM system. My wife has a pioneer premium factory system and she doesn't care about upgrading so where is the market to sustain all of these companies? I don't get it....Sorry, I'll shut up now.

​

I've got this unknown amp new PCB, it indicates 6BM8 tubes in the small text. Text reads: Experimenter's 6BM8 Push Pull Stereo Amplifier...Richard Sears Rev 051810. Does anybody know this board or have a schematic for it? Seems a waste to throw it away.

I found this IC in a ES-Audio DAC. The German Company no longer exists. I presume the IC is a DAC as it is connected with caps to the tubes.
It is a 10-pins tiny SMD. The bigger chip is a Cirrus, probably a CS8420. I found no digital input receiver.
Very little information can be found of the complete DAC with 5 tubes and a weight of 13kg.

4x22.000uF 88.000uF per channel
2x 250W 2x19V
130€ + post EU

Hey there, just joined the forum, currently planing on building myself some SyntripPs to go with my lonely TH12 tapped subwoofers

Greetings Maxi

Hey, hoping for some observations on these crossovers I picked up for a little Cerwin Vega project I have planned with my brother. I have a set of Cerwin E-312 and the crossovers are really subpar.. So in thinking about stuff for the both of us to do as a project, I thought of redoing these speakers I have in my workshop.

Here is the crossover I picked:

https://www.aliexpress.com/item/1005005705670791.html

First off, I'd probably do some obvious things like remove the cheap screwed on terminals and solder wire direct. But in reading reviews, these Russian guys were all sounding off on incorrect values used on the LF portion - the 2.7uF specifically and how it should be larger. Having a look, trying to see what they are talking about, if anything at all. I'd also bypass a few caps too, maybe hard-wire the midrange jumper. Interested in some thoughts. Fortunately there was a pic posted of the backside of the PCB. What do you think of extras to do on these?

Transistors tested. Price 90€ + post. 16 pcs

Hi, I didnt know if I should ask here or at Multi Way but you dudes that are into subs might know. So I have done some repositioning of speakers and listening position etc and listening and measuring, trying to understand what happens. I have come up with a placement that suits me fairly for my LP and the speakers. It sounds ok, still doing tweaking with speaker stuffing (its TQWT) that changes things quite alot. Lately I have also added two subs that are placed ca 1,5 m in front of the speakers. I assumed that I will have to run those thru a dsp because of likely phase disalignment with the speakers woofers. But It doesnt sound or measure as I will have to.

The system is analog but actively crossed at 1000 hz, and I feed the subs with an extra buffer that I have tapped from the LF outputs on the active x-over, so they have a 20-1000 hz signal. The main speakers has a fairly good respons down to abt 40, than they fall pretty steep. So I turned the local low pass button on the subs all anticlockwise to lowest lowpass fq, hoping that they will cut over 40 or so. And maybe they do but not very steep, as seen in measures.

But, now to my main poll. Do you agree that it doesnt look like I have a big problem with phase woofer/subs, so maybe I can skip the dsp and work with some sub eq instead?

Lower is speakers only, both channels, upper is with subs added.

Hi, I am new to here, so i'm not sure how this all works yet, but getting there. I am seeing if anybody out there know's much about old movie projector's they used in theatre's years ago, when you had to make up the picture by splicing and threading the projector etc, and the reason being, that my Dad worked in this industry for most of his life. He is a Hoyt's Pioneer, and knew a lot about movie projector's, as well as his many friends he had in the industry. Sadly, now day's, he is in a nursing home with Dementia, and i have a few things like an old, but i think, functioning head off an old projector, and it appears very old, and a few funny looking Lens's, however, being technically challenged, i am not sure how to put pics on here, but could ask one of the Grand kid's i suppose, they are sure to know. There is also two old reals of movies, maybe 16mm or 8mm, not sure. Anybody else know much about these thing's? A couple of the Lens's are of a Schneider Brand, one is a Cine-xenon MC, Code 37 532. Anyway, if someone who is a bit knowledgeable about these thing's, i would like to hear from you. Thanks. Chris

I've recently switched out a set of EL34 tubes in the attached circuit and find adjusting the bias a rather painful process as the adjustment is done on a net basis for both tubes and it is very hard to get the tubes matched to an acceptable level.

What would be the most efficient way to add in a second trimpot so each power tube could be adjusted separately?

Hello to everyone.
Wanna to purchase Fostex FW220 2 pairs in any shape.

now , as wrenchone sez here , Semisouth goes Dodo .


SemiSouth closure to cost Calif. firm $60 million - San Jose Mercury News


if you're having any useful info about possible ( not left-kidney-right-leg price) SIC-SIT-JFET , put it here .

Hello all,
I want to ask your advise. It's about a turntable. I picked up one a few weeks ago. Cleaned it up, oiled, changed the belt, etc. Looks and works fine ... except for one thing.
I didn't notice that at once, only recently my ear raised a concern. Music sounded a bit faster on this player than on the other. Quick check by the RPM app revealed the reason - 35.5 rpm. No pitch control on this player, no strobe. It is a Sony PS-1350 with a 4-pole synchronous motor. Apparently it picks up its speed from the mains frequency. Mine as expected is solid 60 Hz. If that motor expects 50 Hz - that would explain the slight speed increase.
Any ideas how to correct/fix this?
Thanks.

Avalanche AS1 was an active 3-way speaker made in early '90s in Finland by a small company in Eastern Finland.



It is an active 3-way speaker with analog line level xo and three amplifier boards with Hitachi K135 MOSFET amplifiers.The box is made of soupstone, dead weight 86kg a piece! Drivers are ScanSpeak 21W/8555 (pair) Audax/Polydax 4" mids (pair) and a Dynaudio D28 tweeter.

This pair was for sale at a Finnish hifi-forum, and to my surprise I knew the owner! He had bought this pair just before the bankcrupcy of the company. The speakers had one bass drivers changed but still they suffered from poor sound.

I just had to push the buy button, but for totally altruistic reasons - I will give this pair to my younger son!

Hi folks,
I've been wondering, perhaps not in PSUD, but in LTSpice, is there a way to make a model of a saturating choke with the two following options:

1. Decreasing inductance vs DC current when used into a choke input filter, for the power supply of a class AB amplifier

2. Decreasing inductance vs AC voltage across the choke when used before the rectifier, same application.

I have 2 output transformers from an ARTEC 225 amplifier (EL34 PP). The indication is 5000/30W and the EI-iron measures 92x78x64.
3 individual outputs (I call them A,B,C), a FB? (F) and a CT primary (D-E). I measured the impedance @ 1kHz:

An 8 ohm @ A gives 7 ohm @ B, 13.5 ohm @ C, 32k2 ohm @ D-E and 2k32 ohm @ F
An 8 @ B 4.2 ohm @ A, 12 ohm @ C, 24k5 ohm @ D-E 1k98 ohm @ F
An 8 @ C 2.65. @ A, 3.65 ohm @ B, 13k45 ohm @ D-E 1k24 ohm @ F
An 8 @ A-B in series , 7k64 ohm @ D-E 775ohm @ F
An 8. @ B-C , 4k79 ohm @ D-E 488 ohm @ F
An 8 @ A-C , 2k7 ohm @ D-E 280 ohm @ F

I would like to build an amp with ECC82 as phase shift and EF86 as input stage. I also have 2 power transformers each 100VA/ 700VCT 5V 6V3 an 2 GZ34's (=5AR4).

All Sold

Hi folks,
I have an IK Multimedia IRIG PRO DUO which will not power up. I’ve tried it with the 2 AA batterys (3v line) and with a 9v bench power supply (9v input line) I opened it up and had a good look around. I don’t see any shorts or obvious comment damage. It’s pulling about 0.22mA when plugged into bench supply at 9v input no lights on . And it’s pulling 0 mA on the battery 3v supply. All fuses on the pcb are good. No obvious sign of component damage anywhere. I can trace the voltage past the fuses up to smd transistors but nothing then on the other side of transistors. Teo diodes back to back close to main fuse on 9v input are measuring 1.2v forward bias and open in reverse seems ok. . If I heat this area with iron I get power up to the blue lights. And looks like it is working. But dies away quickly when I remove the iron. I have tested the components on the power section and all seem good to me. It’s strange the 3v input has no current draw at all. If I was to post some pics of the pcb circuit and voltages would it be any help someone might under stand what is actually happening here.

Just wondering has anyone else had power issues with this unit and maybe had a fix.

This is a link to the unit I am trying to get working.
https://www.soundonsound.com/reviews/ik-multimedia-irig-pro-duo?amp

Thanks in advance

Good morning gentlemen, I would like to purchase a loudspeaker for ultrasounds with a frequency greater than or equal to 20khz. But I'm here to ask you which loudspeaker to choose, piezoelectric transducers like those of ultrasonic cleaners or magnetorestrictive transducers like tweeters, I would like a lot of power 100W or more, and frequencies greater than 20khz. I hope you can help me, thanks

I have wasted most of today trying to do just that. I am unable to log in due to some technical (?) glitch and that infuriating chatbot keeps shunting me down useless links to FAQs that don't even come close to addressing the problem. I managed to make contact with most of the employees of the ebay call centre in India but after listening to their well-rehearsed scripts of how wonderful I am for being an ebay member and they would be delighted to help, I am no closer to a solution. Does anyone know of a way to cut through the ******** to get help?

I have 17 3a5 that I dont need I m asking 25 euro + shipping.

Hi people.

I own a single speaker Energy Veritas 2.3 and drivers to make one more.
I don't have a second crossover neither a second cabinet.
I am planning to clone the crossovers and also the cabinets.

The question is..

The bass port system is not so easy to clone.
I can find almost the same dimensions on bass ports on the market but it would be placed flashed at the baffle without the edge outside of the cabinet.
Does this will change things dramatically?

I'm posting photos to give you an idea.

Thanks in advance.

Hi everyone,

I am starting a project to design an audio system for my home by reusing different woofers that I have taken from different speakers, systems, etc.
I read a student's thesis from 2009 on sound engineering and acoustics, and on the calculation and design of an acoustic box for a JBL woofer.This paper helped me a lot to understand the calculations behind the design of acoustic boxes, and to be able to calculate a box for my woofers.

The problem is that the design exemplified in the thesis is about a box for a single woofer, and I have several woofers, with different Thiele-Small parameters, which come from very different audio fields, so I don't know how to calculate a box. to be able to have all the woofers in the same box, or if it is not possible. I also don't know how I can see the theoretical response of the box with the woofers, since in programs for this, like WinSID (which is the one I use) you can only see the behavior of one or more woofers, but of the same model, not of different models.
So my main doubts are, how can I calculate the same box for the same woofers, given that they are different models, and with different Thiele-Small parameters. And my other question is also how can I see the theoretical response of the box?
I would also like to be able to better understand the Bode plot implemented for the responses of the woofers, since I do not understand it 100%
Any kind of advice, tips, etc. I would also greatly appreciate it.

PD:I don't speak English that well, so all this writing was translated by Google Translate, in case there are strange things in the writing, hahaha

Hello! Tube-head since 1960.

Hi I have one of the above amplifiers and it randomly jumps the input. I believe this is due to a worn/dirty rotary selector control. So I thought I'd source a replacement part, but have been unable to find one online. I did find one for the PMA535R on ebay, which looks the same (https://www.ebay.co.uk/itm/154325062392) so does anyone know if the PMA535R one would work with my PMA355UK. Also asuming it doesn't would acquiring a remote control and using that to change input channels provide an alternative. If not can anyone recommend a good repair technician in the UK, preferably Bournemouth and surrounds that might be able to clean and fix the switch?

Hi,

I am planning a class D guitar amp:

• TPA3255 based amp
• stereo 2 x 120w into 8 ohm
• either 6.5" or 8" speakers
• coaxial or extended range
• compact enclosure

Ideally it should be full range - so it can be used for other instruments ... if needed. I need advice ... especially for speakers. Coaxial would be preferred, but with max price around 100 USD per piece. Other ideas are also welcome.

I someone has made similar build ... I would be happy if he/she could chime in.

cheers

I picked up this little amp a few weeks ago and was just wondering if anyone here could offer advice on tubes to improve or change the sound?
Here are the details from the builder in 2010.

I built this little amp about 6 months ago and it's seen about 25 hours of use. You could think of the amp as a JE Labs "Simple 45" except it uses the 1626 output tube (the schematics are virtually identical except for output tubes and naturally different operating points).
The tubes include a 5U4GB rectifier, a pair of 1940's Hytron 1626 power tubes and an RCA JAN Black Plate (graphite coated envelope) 12SL7 driver tube (all tubes were new with the amp and have about 25 hours on them max).

I've really enjoyed this amp in my Den and used it to drive some custom made 94 DB single driver speakers with plenty of volume and dynamics for my listening level. The tube puts out about .75 watts per channel so more efficient speakers will be needed in a larger room. However, I let one of my friends with a pair of Lowther Alerion speakers at around 94 db efficiency listen to it in his larger room and he really liked it. But he already has two of my hand built amps and couldn't really justify buying another one (he has several other tube amps as well) so this one is available to the public at large.

The amp has an overbuilt power supply and is really quiet. I used a seperate filament transformer with center tap to help with hum balance and avoid any coupling noises between windings in the power transformer which I think helped.

Some other details about the amp:

-- NOS USA Made Pyramid Paper in Oil Coupling Capacitors

-- Teflon Jacketed Silver Clad copper for all signal carrying wires.

-- Made in USA new Edcor output transformers

-- Super short signal path, with an attempt to use only the leads on most resistors to minimize the number of solder joints.

-- Lead free Kester 3% silver solder used exclusively

-- Vintage Power transformer that I picked up on Ebay last Summer (spray painted it a hammertone black to match the plinth).

-- A hybrid star ground that uses a short silver clad copper bus bar that is reputed to be quieter than a straight star ground (high currents are kept from commingling with sensative signal circuits).

The amp is point to point wired, although I did build the power supply on a perf-board to conserve space and to better group the power supply grounding node.

Hi to everyone.
What is better about sound from these Heil?
I see on datasheets, Beyma little bit better.

I like long walks through the electronics section in JC Penny, dreaming of the totl MCS components. A sound system with synergy, that can move enough air to compress my chest. Lazy mornings scanning Marketplace for depreciation based mega bargains. Don't like people who don't like cats. Bluetooth streaming is something we did on bicycle handlebars, I'm pretty sure, not meant for audio. How many pieces of "vintage" audio gear do I need?
Just one more lol. Do you turn your ac off for as long as you can stand it during critical listening sessions because it
a)creates too much background noise
or
b)draws power needed for the cannon blasts during the 1812 ovature
or
c)both
But seriously folks, many great brains on this site. I have a few "projects" than are stalled and I'm hoping an infusion of knowledge from all here could help.

Hello Guys,
I made a video on YouTube about turning on the subwoofer unit with the control pod.
I hope this can help you using the multimedia speakers system without the control pod.
Thanks
Login to view embedded media

audiolab m-dac restore from lake west to original firmware - just bought this dac and want to restore to original - any advice please

Hello. I have an FBT MXX 4 active speaker and although it works, but it has a very strong hissing noise in both speakers, bass and treble. With no input signal, if I turn the volume to minimum I have absolutely no noise, but if I increase the volume potentiometer the noise is heard. I checked all the electrolytes and they are ok, cleaned the potentiometers, the voltages are ok. If you can help me with an advice.
Link to the schematic https://fastupload.io/7f7d2c326ab80f3d

Just wondering, in this day and age it might not be applicable to anything at all.
But to this day and age, I have only seen and used various amplifiers of these different topologies:
Class A, AB, C, D and T.

I have never even seen a Class B amplifier, neither as a finished product or in use as a DIY solution for a particular use-case.

Can anyone point me towards a Class B amplifier in practical use, or as a finished "off the shelf" product?

All,

I would like to share with you the experience I got with a Chinese version of the AMB Sigma 11.

I didn't know the existence of the AMB sigma 11 project thus many months ago I went to Ebay to find out a good-and-cheap LPS to supply my Allo USB Bridge and Chord Mojo.
I found this unit:

ZEROZONE Super-PSU 30VA DC5V 2A Alimentatore LPS Linear per fonti audio | eBay
This was enough expensive to make me think this was a good one.
Few days ago a friend of mine that is helping me modifying my Mojo with supercaps (the battery died) suggested me to implement the Sigma 11 LPSU since it would perfectly fit with my equipment.
At a first sight I identified the PCB of my LPSU was pretty similar to the sigma 11 project.
Actually I discovered there are some Chinese traders that are selling SIGMA 11 modified board without any license.
Vary bad. Shame on me since I bought one.

Now I spend some time to draw the electric schema of such unit.
Please find it below. (in grey the original component value as per Sigma 11 project).

Beside the component quality that is pretty high (Nichicon capacitor, given they are genuine...I cannot say that), the schema - attached - has been changed in few parts.
Let me list for you:

1. C18 (secondary filter right before the output) is now a 3300mF (even if the PCB is indicating a 10000mF capacitor) electrolytic capacitor (should be a 1mF polyester)
2. The gain of the regulator output is obtained with a 4.3V Zener * R8/(R10+Trimmer) = about 1.3. I suppose they introduced the trimmer to slightly adjust the output voltage. The original schema suggested a 5.1V zener and R10 not installed (Gain =1) for a shorter and simpler schema.
3. C14 3n3 instead of 3n9. My guess here is they just finished the 3n9 and put a 3n3 capacitor...
4. C13 has been lowered to 47mF instead of 100mF. This is part of an RC filter with R3 (1k as per original schema) to lower down the zener noise. Sincerely this seems to be a go-for-a-cheap solution...
5. C11 and C9 lowered down to 100mF and 47 mF instead of the original 470mF and 100mF. They are filtering the voltage reference and line regulation. go-for-a-cheap-solution even in this case?
6. C5 the input filter capacitor has been lowered to 4700mF to 3300mF (even if the PCB is indicating a 10000mF capacitor)
7. rectifier diodes are MUR 1560 instead of MUR 820. Actually they are a bit slower (60 ns vs 35ns ) than the original but they have an higher Vf since they drain about 1.5 V MAX each instead of 0.9 MAX. This could the reason why they chose to have a 12V secondary voltage (through a cheap R-Core Xformer) instead the suggested 9V to obtain 5V output.

Overall they increase the output filter from 1mF to 3300mF (or 10000mF as per PCB indication) but they reduced the filtering of the internal PSU stages (voltage reference and error amplifier). Unfortunately I do not have an oscilloscope thus I cannot say how low-noise is the output.
What do you think?
Would it worth to change back all the modified components to fit the original schema?


Thank you in advance to whom would like to help on this topic.

I was curious if anyone here had any experience with the AD ADA4899-1? It seems to be a very nice part but I haven't seen where anyone has used it or has opinions.

Thanks,

Hal

Hi.
Couldn't get answers in another dead thread, so here goes:

Got these boards from China and am delighted with them EXCEPT the gain is way too high for my application (triamplified speakers in a conventional hifi system).
Gain seems to be ~32-35dB, and my other amps ~27dB.
I have read that the boards use two resistors in a voltage divider to set the gain.

Hello,

I have been bartering, horsetrading and building audio equipment and speaker systems my whole life. I do love the soft sound of tubes and solid state both. My system currently in use has been in service for over 30 yr without a bunch of updates. I have been out of the loop for a while! I am building a new audio system for a new house and have my speakers, amps, and an old SAE 2100 preamp. I am looking to upgrade the preamp to allow for a remote control, streaming NAS and online Qobus and audiophile quality. What is out there and what are you guys using. Doesnt need a ton of BS. I dont even run an equalizer as my room and speakers get tuned and leave everything flat. I just want something modern with remote control and superior audio quality. Simpler the better and also something that if it has a display can be blacked out important too!

Thanks,

Tim Naples, FL

Hey DIY colleagues,
I own two Auralic Aries G1 and want to improve/change the existing power supply PCB with a new self developed one. I searched all the latest posts here in the forum and decided to try the LT3045/L3042 NPN version. But to be honest I just have several degrees in economics but none in electronics 😊 But after a few other power supply projects in KiCad and want to reach the next level... but learning can only be achieved when somebody tells you how it works in reality.

I hope you can help me regarding my project or perhaps you are also interested in this board for your Aries G1. Ex factory: Two LM317 regulators and standard brigde rectifiers (without snubber resistors). Have a look here: https://positive-feedback.com/wp-content/uploads/2020/09/img-4-auralic-streamer-review.jpg

What is the plan:

• 2x Talema transformers (7V and 15V)
• Epcos chokes
• LT4320 active rectifiers
• a bank of Panasonic FR 12mOhm capacitors (35V 2200uF)
• 15V System Rail: LT3042 with NPN (for the 15V system (Display, XMOS controller,….))
• 5,6V clock Rail: two parallel LT3045 for the 5,6V clock rail.

Measured power consumption of the Aries G1:

• System Rail: 16,8V @0,4A . But I tried it with 15V @0,5A ZeroZone Supply and it also works flawless.
• Clock Rail: 5,6V @0,3A. Should stay at 5,6V

My questions are based on the attached circuit schematic:

1. 15V System Rail: I want to reduce the heat dissipation and use the already drilled mounting holes for the TO-220 LM317 regulators. For the 15V system rail I used NPN Transistors as shown in the LT3042 tutorial from Analog (Increasing Output Current of the Ultralow Noise, Ultrahigh PSRR LT3042 200mA Linear Regulator | Analog Devices) . Question: Should I use this NPN based circuit or switch to a parallel LT3045 based solution? Parallel-version: How much heat will be produced on the LT3045 chips? Perhaps somebody can help me to calculate this? Do I need extra heatsinks?
2. 15V System Rail: I tried to implement CRCRC resistors after the LT4320. Is my calculation correct? If not, how can I calculate the correct CRCRC resistors? You can find my calculation way in the circuit drawings.
3. 5,6V Clock Rail: Same CRCRC resistor questions here.
4. 15V and 5,6V Rail: I tried my very best in copying and adopting the LT3042/45 schematics I found here and on the Analog site. But can you please check if I made some faults choosing the correct resistor values?
5. Output capacitors: Analog only recommend a small 10uF (or a little bit more) on the output. But I found several LT3045 implemtations with a lot more uF… What would you recommend?
6. LT3042/45 sense line configuration: Some implementations have a third contact for the sense line (Plus, Ground, Sense) and some implementations already combined Plus and Sense in just one output. What would you recommend? (My opinion: Seperate Plus and Sense and combine the two Plus/Sense cables in one (Y-Version) – Am i right?).
7. MOST important DIY Audio question: Can you recommend any improvements I should consider 😊

Best regards
Andy

I hope you keep enjoying the company we provide around here today and the coming years...

Cheers to you Mr. Cool!

While walking past an appliance store in '76, I heard something that ignited my passion for music🙂) I saved up all summer to buy that Marantz 4220🙂 The following year I heard a real stereo, & gave that Marantz to my Sister:-/ Saving for 3~6 months at a time, I bought: Dahlquist DQ-10's (at 1st run by that Marantz), then Denon DP-1200 turntable w/ Grace G-707 tonearm & Win Labs SDT-10 Strain-gauge cartridge, Audire Model 1 power amp & Audire Diffet 1 preamp. My next speaker was a used Magneplanar Tympani 1-D. Due to the wonders of online resellers, I've acquired: an Audire Legato pre, Model 2, Cressendo & Forte amps, MG-IIIA, 2 additional Denon/Grace, Strain gauge setups, ... SAE, ESS, Marantz (again!), Silver Pioneer, & tons of DBX stuff🙂) I'm here to learn more about my (& Other's) stuff!!

I own the preamp in the object which came to me with no user's guide.

While cleaning the boards inside, I've noticed there are two micro switches in the phono board, which is capable to amplify MM/MC cartridges. Are they useful to set different capacitance/impedance loads by any chance?

Will you be so kind as to explain how the four positions work? Anyone who is able to post a scheme or provide the user's guide? Thanks.

I have for sale soft start module for power amplifiers. Module was never used in practice. It could be triggered via push button or shut down in case of high temperature of case/heatsink. All temperature sensors, wires, contacts...etc. are included. Module was bought via Aliexpress, but looks the same as this:

https://www.audiophonics.fr/en/soft...ard-and-protection-for-amplifier-p-10225.html

Price is: SOLD

Hi ! i have a curiosity about this kind of drivers

i wonder what kind of advantage provides the use of those little lenses around the dome
Clearly they limit H and V dispersion But what are the benefits versus normal domes ?
Thanks a lot

For some time I would like to have an audio-transformer suitable for measurements of class-D-amps with BTL-output configuration
that will be converted from symmetric output to asymmetric scope input.
With the primary driven by low impedance amp and the secondary more or less unloaded best signal integrity may be expected.

The problem is non-linearity of the magnetic core increasing drastically with signal level and to low frequencies.
There exist special magnetic highly linear materials, but not available to me.
And available audio line-in transformers cannot handle loudspeaker levels.
They simply are too small, here it is size that matters.
So why not use one off-the-shelve toroid mains-transformer -
connecting the primary 230V winding to the amp
and the secondary to the scope.

In my stash I discovered an 48VA toroid with 24V secondary, giving close to 10:1 or 20dB attenuation.
I think there is nothing special with this, so similar transformers might yield similar results.
For the test I fed the primary with my MOSFET-Class-AB-Mono-Block, driven by the MOTU M4 soundcard.
The secondary was connected with the input of the soundcard.
Sample frequnency was set to 192kHz.
Here is the summary of THD measurement at various levels and frequencies.
All in all this is much better than I expected after disappointing measurements of audio line and mic transformers.

Hello, I have a friend who have a a pair of the original ATC SCM12 model. It performs really good for its age, but it is a speaker on the "dark side".

The tweeter it uses is the Vifa D26NC-15-06 which is supposed to be flat and with a little spark in the 16khz area, so we don't understand why its dark sound.

I want to ask if it is possible to make some kind of mod in the crossover to make them a little bit brighter. Here are the pics he has sent me of the crossover. Thanks in advance for any help 🙂

Attached is an American-German developed 2" mid-dome driver found in the ADS and Braun speakers. The unit in the photos was taken from ADS L980/2 speakers. As can be seen, the magnet is covered by a large metal cup on the back, blue arrow. I've acknowledged that the cup was installed there for forming a chamber or a closed enclosure to lowering the Fs of the unit.

In the L980/2, the high-pass crossover for that mid-dome is published at 450Hz. In addition, its bigger brother which utilizes the same midrange unit, the L1590/2 speakers, is published at 350Hz. While the smaller brother, the L880/2, is published at 550Hz, but it has no metal cup installed on the back of the magnet, as their bigger brothers, for lowering the Fs.

What's the trade-off of lowering the Fs, between having and not having the rear chamber on the back of the magnet? This question also applies to the large surround usage, in the picture of the front of the dome.

I’ve got two power amplifiers for the candidates: a 5-channel Soundstream Reference 405 and a 2-channel Nakamichi PA-302. I’m going to employ both of them to my speaker sets.

Here is the list of my speaker system:
Front speakers: 4” Boston Acoustics CX-4
Rear speakers: 5 1/4” Boston Acoustics Pro 5.0
Subwoofers: 10” MB Quart QM250 SUB

Definitely, the MBQ subs will be driven by the SS amplifier, as the SS is 3/5-channel and provides a subwoofer channel.

I have two options for the combination of the speakers and amplifiers:

Option A)
Front: Nak + CX-4
Rear: SS 405 + BA 5.0

Option B)
Front: SS 405 + CX-4
Rear: Nak + BA 5.0

It seems to be an easy question for somebody but there’s a little complexity, for me, there.

The CX-4 is labeled power capability of 20W nominal and 40W peak. While the Nak is rated power output at 80Wpc and the SS is rated at 40Wpc in 3-channel mode (bridge). All values are based on 4 Ohms impedance car audio standard.

So, I’m not sure if option A, using the CX-4 with two times power amplifier (the Nak), would harm them or not. And, for option B, the SS has lower power but in practice it’s recommended to set the gain of the front amplifier higher than the rear amplifier, thus, the front amplifier should have more power than that of the rear.

Which option do you prefer?

Hi All,

Just wondering, is it a good idea to use a single ended amplifier for headphones, given that the phone impedance vary over a very wide range? I have come up with a circuit as attached, and wonder whether it will work as an output stage of a headphone amplifier? Appreciate any comments, on whether it will work, or any changes that will make it work. Thanks!

Hello,

I can't seem to solve this problem:
Technics amplifier SA 150.
Using Aux in via a cable (RCA/3.5mm stereo) from my laptop
Laptop has mains power supply, no earth.

I get a severe computer like random noise.

Quiet when disconnected on the amp side.
Noise goes away when I run a short wire from the amplifier antenna shield ground to one of the RCA input grounds. - Solved and almost usable.

However, I now have some mains hum which goes up and down with the volume so it is from the input.
It stops when I disconnect the cable on the laptop side.


It does not stop when I disconnect the laptop power supply (run on battery).

I previously used my Marantz SR340 amp for this purpose with identical setup and there was NO computer noise and NO mains hum.
All this has been introduced by swapping amplifiers.

How can I troubleshoot and fix this this?

Best regards
Bernt

As a relative newb to DIY audio, but having a solid ability to solder and follow directions, though lacking understanding of theory, I see all these amplifier builds, but nowhere near as many preamplifiers to control volume and/or tone? What would be a good beginner level preamp kit or build for someone who already has a nice class A amp? I am finding out that "front end" "line stage" "preamp" and more can all mean the same thing as far as control goes, so it can be very confusing for the beginner. If needed, the amp I'm trying to control is a Pass Aleph 30. I have a phono preamp already, so just a stereo preamp is what's needed. Class A preferred. I've been going cross-eyed trying to figure this section out. Any help from the gurus is appreciated.

Cheers!