https://techtalk.parts-express.com/...minisculities-and-goosebump-pr-bandpass/page3

@wolf_teeth
Can we try this with the tangband w5-1138f and the $40 7” dayton epique passive radiator?

https://www.parts-express.com/Epiqu...iber-Cone-Passive-Radiator-295-114?quantity=1

Hi All,
Have a few Sanken S-40W, S-60W, SP-40W Modules to clear. They are Not Brand New but NOS , never been use.
Please Note some of the modules case were scratch , they live their life in an unprotected plastic bag.

I have had a pair of Kef c7 first hand for several years. I really enjoyed their sound.

In January one tweeter stopped working.
So I unscrewed the face plates and did a tweeter switch (from one speaker to the other) to check if this is it (and unfortunately it is tweeters fault) and it is not a crossover issue.
I have been in contact with the representative in Greece but for 2 months now they can't find it.
They tell me that because of covid everything is late and wait some time more etc.
So i am alerted that i won't find anything and i am in search for a speare one. I've also looked on ebay but I can't find it there either.

I'm desperate, I liked their sound and I didn't want to change them. But I don't see any other solution.

I emailed gp electronics & acoustics co. ltd which is probably the OEM manufacturer. No answer.
The same for KEF on FB.

Searching the internet I found the following (which comes from the attached pdf)




The speakers are the ones at the attached picture. They have a front wooden/black painter plate to cover the speakers bolts.Tweeter is shown at the other picture.

Any ideas with what tweeters i can replace the old ones? Maybe a modification ?

Hi everyone!

Let's assume, you've drank a lot, are agitated or not able to sleep, maybe too much caffeeine, it's late at night, what do you do? Pestering the forums with stupid questions, arguing about things of the past, ponder about what driver to use? Please tell me to distract me from my sleepless night..

I have a KEF C series system that I am trying to maintain and keep alive. Unfortunately my tweeter failed on my CLR6 centre speaker. And now I'm trying to figure out how to repair it.

Hi everyone,

I'm kind of new to Audio DIY although I've been making all kinds of DIY hobbies through the years, from aeromodeling, some woodworking, 3D Printing (own a Voron), etc...

Made a Protodac as first DIY audio gear recently and been enjoying it quite a bit with the rest of the audio gear (only had a turntable and the TV connected to the amp... and a DAC/Streamer came quite handy for when I don't wan't be be playing with disks so much)

Hope to learn much more here!

Regards,
Gonçalo

I am an audiophile and often looking for affordable improvements to my audio system. I like analog and natural sounding systems. During an audio fair I heard the Pearl Acoustics Sibelius speakers and I was immediately sold. Unfortunately the speakers are too expensive for me. Thanks to a thread on DIY I got the idea to build the speakers myself. These will be the 2nd speakers I build myself and probably also my last!!!

Andy from from the cold, dark north of England. Not much into DIY to be honest. But “enjoying” a couple of the threads on here…

Update: Please make sure you have read Jason's post #513 before replying into this thread instead of using the new forum we have created to collate new issues called "New Platform Issues".

After a 36 hour marathon migration, we have our new home!

It was important for us to get off our old software as soon as possible, rather than wait for the new software to be perfect. Your bug reports and constructive feedback are welcome. They will help guide us make the right decisions to improve the site in the future, and to clean up any issues.

Planning, development and migration was performed in partnership with Xenforo experts Audentio. You might see some of them chime in to this discussion thread.

PS make sure you check out the theme chooser which gives you three theme options - light, dark, and classic.

Hello, I have a problem with an alpine MRD M300 amplifier. Does anyone of you have information about it, specifically the oscillation stage?

I had two Fluke 8010A Bench Meters both with broken LED displays (they go black). First time I looked at replacing the LCD with LED it looked impossible because the common BP (backplane) signal reverses phase constantly relative to the segment drive signals (that's what LCD displays need to work).

A few months later I had another look and realised that a pnp transistor could use the BP signal to strobe the right phase for four Common Cathode Seven Segment LED's by doing this:-

"Connect BP signal to base of PNP transistor via 3K9 resistor, Connect its emitter to all four LED common cathodes, connect its collector to - Vss
(Note BP drives U6 for the decimal points)"

Solder wires from the previously LCD connector to your four common cathode seven segment LED's. See attached pinouts etc. Only three of the LED decimal points need to be connected to U6.

The ICL7106 doesn't have much drive but its enough to get a tidy LED display, don't include any series resistors. The LED's take a bit more current so its a good idea to increase the power supply smoothing capacitors (double the uF value)

So end result is an excellent and accurate Fluke 8010A with four digit LED display (the MSD LED only displays "1" and the negative sign.

The Fluke 8010A has a very small supply transformer and only consumes a few watts. I have one of the 8010A's permanently on monitoring a battery voltage.

Hello All

I have been repairing Klipsch subwoofer amps for about 15 years as a hobby. I have decided to start blogging my repairs and eventually do videos of each one. This thread is intended to be a blog and a resource for information. I will try to answer repair questions as best I can. Comments and tips are also welcome, If you do not have the experience or the tools, PLEASE do not attempt any of these repairs. You will only end up damaging the board and it will end up costing more for a tech to repair the damage. If you do not have a high quality vacuum desoldering station (Hakko or Weller) and a current limited mains supply, you should not be working on these amps. These subwoofers do not have any user serviceable parts inside. If you open up the sub or attempt any repair you see in this thread, you are doing so at your own risk!!!



The PDC board 660038RA (main supply control) is almost always the main failure mode of these amps. The glue that was used becomes conductive and kills the board and the fets (planned obsolescence?). These boards are typically made in China and are super easy to damage. If you don't have a desoldering tool you MUST cut the board off and remove the legs from the thru holes one by one. Once the thru holes are damaged the repair becomes a difficult hack job unless you have a thru hole repair kit.



The other most frequent failures are the Bash control board and Q5. If Q5 is SOT-23, it needs to be replaced with a TO-92 2N4401. This mod was done on later revisions most likely due to warranty claims.



I have made a schematic of the PDC board and I also have made replacement boards (I do not sell or supply these boards). Sometimes they are so badly burnt, they have to just be replaced.

Hi,

My name is Jakub. I am interested in building a single driver speakers myself and that is why I am here 🙂

Regards

Anyone have a circuit drawing? I'd like to implement a soft power switch..

Hi to Everyone !
I seem to see a continuous and enthusiastic search to achieve the lowest possible levels of harmonic distortion in circuits
Every now and then I read that below a certain level (that I have not understood well) any improvement in terms of lowering harmonic distortion practically becomes inaudible in normal listening conditions and can be appreciated only with the best testing lab gear
Question Is there any agreement on what this level is?
Thank you very much and best regards
gino

P.S. I well understand that The lounge should be a place to discuss topics that are not audio related,
But i have sometimes doubts so generic that do not fit in any specific discussion and other members could easily get annoyed by maybe trivial topics
Thank you very much

Hello everyone.
Over the past week, there appears to be more than just a bit of interest in Altec Lansing. You know, the real ones.

We have had a member selling some. (there was more in that thread after they were sold than before) A member building a system I thought may have been modelled on an Altec, enquiries about cabinets, same raving, and why not! Even a mod got entangled in a hijack. No names.

So how about a thread for Altec Lansing? It can cover anything you want in the way of their speaker range. Cabinets, mods, pictures, data sheets. Even experiences. It could include the MM stuff (they are good for what they are) It doesn't have to compete with Lansing Heratage, however it could compliment it.

For those not fortunate enough to have heard these speakers, most of us that have, even in the long distant past, do not forget the sound. And many will try to emulate it.

So how about it? Show us your Altecs, share the pleasure and the dramas. Lets show the current manufactures some real magnets, cones and horns.

Geoff

Hi Guys,

I am seeking some advice regarding what could be the issue with my turntable. I am experiencing a somewhat distorted sound while playing LPs - it seems that it mainly affects the instruments and to a lesser extent the vocals.

I have made a quick video recording here: Login to view embedded media
It is supposed to sound like this: Login to view embedded media
Do you think it is the Pickup which is done? or might it be an adjustment thing? needle pressure e.g.

i bought the turntable used, close to a year ago, anticipating the Pearl 3 RIAA, and it has been playing great since, however it is my first turntable so i am not that experienced regarding things that might be going on in a turntable. It is a Rega P3-24 with a Rega Exact pickup.

I have tried a different RIAA - it did not change anything, and there is no issue when i stream something, so it is isolated to the turntable.

I am researching the next level of audio performance as I have pretty much topped out, at least from my perspective, in the box store and online sector of home audio. I have an Onkyo TX-NR6100 and a mix of Klipsch reference and reference premier speakers for a 7.2 HT with Atmos main system. I also have an Onkyo TX-8220 with some JBL Venue series speakers that I have on zone B from the 6100 in my room. I have this setup so I can listen to my tunes throughout my place without having to turn a single system up loud enough to get complaints from other tenants. Lots of speakers at low volume works. I started out with a TX-SR393 and a "HT in a box" speaker package but I spend about as much time in my room as I do in other areas of the apartment and if I turned it up loud enough to hear in my room, the neighbors would complain.

I know I could get a little better out of general store bought equipment but it seems like pretty much a lateral move with only a little better performance so I'm researching moving into a higher level of audio system. It's a balancing act for me because I don't have a lot of funds to throw at it. It's taken me well over 5 years to work up to what I have by waiting for big sale events and wheeling and dealing in the used market but I've done pretty well. To buy everything I have at full retail would be significantly more than I actually have into it. I'm actually quite a bit below half of what full retail would cost and it's all in either new or like new condition with the exception of the JBL venues which I have "made my own" by replacing the grill cloth and painting the accent panels and trim rings and replacing the "JBL" decals with actual aluminum badges. I also had to replace the amplifier in the Sub 12 and sounds like I'll also have to replace the one in the Sub 10 eventually.

The system as a whole sounds really good and suits my needs and looking into this "next level" I'm finding that in order to get a what I consider marginal amounts of performance, a lot of money is spent in the form of devices used to refine or "clean up" the audio signal from the source. It's also been my understanding that adding devices to a system also adds noise. I'm assuming then, that it all depends pretty much on the quality of the devices which in turn depends on how much it costs. So is it a toss up on initially spending more on source equipment that outputs better signals than adding devices necessary to refine the signals from lower priced equipment, or does one still have to add expensive signal refining devices to already expensive source equipment?

If that's the case, I believe I will just settle on the pretty decent stuff that I have and find another hobby. Any thoughts on this subject are much appreciated and thanks in advance.

Due to health issues, I can't complete this project so it's here for sale.

I originally bought this bundle from someone on this forum, the original thread has some details and pictures

https://www.diyaudio.com/community/...id-transformer-heatsinks.384794/#post-7042520

I'm looking for £350.

Based in Bristol, UK.

Currently looking for UK sale, ideally collection but can post.

The Kef B200 was in loads of speakers around the 1980s, and there still seems to be a few about.

Rubber surround so no foam to rot.

So the question is "how good is it"? Is it worth using for a 2-way speaker project, either sealed or ported?

Is it still competitive or are there better 8" drivers available these days?

The SP1014 is the common one with the smaller magnet. Are the larger magnets any better, like SP1039?

And I gather the crossover needs to be 3K or below, but I haven't seen any frequency responses for the B200.

So - worth using or pass?

Hi all,

I'm thinking of playing around with an open baffle monitor using these drivers:

1 x GRS PT6816-8
2 x GRS 10PT-8 (parallel, did two of them for the excursion and sensitivity to bring it up)

Just fooling around in X-sim to see if they're even remotely compatible in a meaningful way without requiring super complex passive crossover. But, I'm very weak with crossover design and mostly use full range drivers. So any help is appreciated if anyone has a moment!

I tossed in the drivers in X-sim and did a simple set of low pass and high pass to get a general idea of things and how the impedance would be.

I don't need it to be super flat. I mostly just want to get to about 70~80hz on the low end before I crossover to a sub. I imagine I will do this on the thinnest baffle I can and will add some wings assymetrically to the sides, then measure, then re-do the crossover. So this is more of a preliminary attempt to see if they will even work together passably. I have the PT6816 drivers, but I do not have woofers yet, so I'm open to something superior for the role in a similar price range (~$30 per driver).

I've attached my X-sim model here to this post so it can be loaded with the drivers.



Thanks!

Very best,

Hi, I'm a retired engineer who dabbles in all types of repairs - auto, appliances, and occasionally electronics. I live in Canada, near the US Border of Detroit. I own a Klipsch sub-10 Subwoofer that won't power up, and I'm looking for help to get it functioning again.

This is my first series crossover so I would like someone to sanity check my work.

Background info and disclaimer:

1. Yes, I do know these are bass heavy. This whole build is made around some leftover Silver Flute woofers I had laying around. It is what it is.
2. In order to match the sensitivity of the woofer I needed a low impendence tweeter which forced me to series crossover. I can do it parallel and get to 3 ohm but that will still require a dedicated amp for this build which I am trying to avoid.
3. This by no means needs to be a perfect build. As long as it sounds ok I'm fine with it. It will be much better than the crappy sound bar that is currently at the family lake house.
4. The tweeter is utter crap below 2khz.
5. The woofer has a stupid breakup node at 5100 hz and I just cannot seem to get rid of it with a series crossover
6. This is all measured data.

My KT150 PP project showed a lot of distortion yesterday. I discovered today that 2 cathode resistors (2.2 Ohm each) had gone south. One measured 33 Ohm, another 160 Ohm.
In the cathode lead I have a string of 3 resistors: 2.2 Ohm, 2.2 Ohm and 1 Ohm, 5.4 Ohm in total. With an automated bias module the cathode voltage is compared with a voltage reference. This works fine and I had set the cathode current to 90 mA.

Of course I ordered new resistors today (TO-220 again, now 50 Watt max.). I know the cooling is not exceptional, but with 2.2 Ohm and 90 mA (0.01782 Watt)?

I just cannot understand what may have caused damage to these resistors.

Regards, Gerrit

Hello,

I just purchased the TU-8200DX kit, and although it hasn't even arrived yet, I've started going through my tube stash pulling out all of the 6L6GC tubes I have as well as their relatives. I haven't been able to locate a list of all of the compatible tubes for this amp, other than what is advertised by Elekit (6L6GC, KT66, KT88, EL34, etc.). Sounds like the voltages in the 8200 are too high for the original 6L6 metal base 6L6G varieties, however can someone confirm whether or not the following can be safely used (regardless of pentode, triode or UL modes)?

• 5881/6L6WGB
• 807 (with adapter)
• 6BG6 (with adapter)
• 7581

Any others that I'm not thinking about? Has anyone measured the plate and screen voltages applied to the power tubes in the TU-8200?

Thanks for your help!

Hi,

ideally I would like to sell my leftovers from DIY speaker building for small money in total.
I'm located near Munich in Germany, so you could also pick up the items. I have all the parts for some years, the condition is normally VG+.
Parts:

• 2 circular horns 6" for compression driver
• 2 circular horns 10" for compression driver
• 2 Stage Line MRH-80 high range horns
• 2 WG-300 waveguides
• 2 Stage Line MRD-90N horn drivers
• 2 Vifa HT 200 F/6 tweeters
• 2 Scan Speak D2604/8330000 4Ohm tweeters with attached WG-300 wave guide (wooden adapter). Original front plate is available
• 1 SB 29RDC-C000-4 tweeter. Condition unknown. Don't know why there is a single tweeter :-(

For any questions, feel free to contact me.

BR

Hi, I am interested in building a Hog Scoop enclosure for the 18sound 21LW1400 speaker, similar to the design described here: https://www.freespeakerplans.com/?view=article&id=31:hog-scoop . Currently, I have two of these speakers mounted in bass reflex boxes, but I’ve noticed that the sound doesn’t seem as powerful when used outdoors.

I would like to know if the Hog Scoop design could provide more SPL compared to the bass reflex enclosures I am currently using. I am particularly interested in improving low-frequency performance and achieving a louder and clearer sound in open spaces.

Thank you in advance for your response and any suggestions you can offer regarding my project.

JBL M2 tweeter (D2430K) pair, in sealed boxes. Only Europe area. Price 1400 Euros, plus shipping.

My Mark Levinson 380S preamp forgets its input names and gain settings after it is powered down and back up. If I reprogram them they are restored, however, after powering down and back up at a later time they are forgotten. There may be a default labeling of inputs when not programed, for instance input 1 always comes back as CD 1. Is there a charged capacitor that maintains the settings of a memory chip or perhaps something wrong with the memory chip and does anyone know which one it would be? The preamp works normally otherwise.

Hi there,

Couple months ago I decided to step up my audio measurements "game". Bought dbx RTA-M uncalibrated microphone (no downloadable file, no mentioning that it is somehow calibrated, just the overall quality claims from manufacturer). It was praised by local salesman, who had just this one and couple of other models in stock with similar pricing. None of them with calibration file. As it was my first reasonably good measurement microphone, I assumed, that it is more or less flat and is more than sufficient for homemade speaker projects. But the doubts were there and...

I bought cheaper, but calibrated Dayton EMM6 couple days ago and... Now I got real headache. Below are the measurements of dbx and dayton. No matter what levels, no matter what REW options - the curves are exactly like this:



I admit, that the speaker Dayton PS95-8 I am measuring has some rising response, but it is around the levels of dbx, which is similar to manufacturer curve, I do not fully trust dbx, but Dayton is DOA, landfill or similar quality. Calibration file of Dayton is in ~3dB range, there is no curve similar to ~20dB difference. Or maybe I am doing something very very wrong?

My ears are good and I understand that I am not measuring flat speaker with flat microphone, but the real perception of sound is in the dbx curve.

p.s. I will try to get some local help to compare my mics to the some more expensive one, stay tuned.
p.p.s. dbx was used ~10 times/days, dayton ~2. There are no damage signs on any of them, they are new and look as new. Handled with care when in my posession.

Looking for an Icepower module with integrated powersupply in the European union.
Around 2x200W or higher.

Anyone willing to sell me one and ship it to Sweden?

Not sure if this is the best forum to put this…

https://audioxpress.com/news/tascam...e-audio-field-recorder-and-timecode-generator



dave

Hi,

Anyone have any recommendations for a 4" driver that will be happy sealed and can cover 100-5000Hz well in 2.5-way DSP crossover, available in Australia for no more than $175AUD per driver?

@mayhem13 recommended the ScanSpeak 10f-4 but I can only seem to find the 8ohm here.

Thanks!

Hello

i am Dimitri from Greece.

Thank you for your acceptance.

i think i need to reintroduce myself due to a long time being inactive in this site.

I am a huge vintage speaker fan.

Hello, fiiends!
I need to power pre-amp based on NJM4580 chip. According to the datasheet, the chip is powered by a voltage of ±2 to ±18 volts. The input signal will be ±1V, the output no more than 3V. Most of the circuits I have seen use a voltage of ±12-15V. Will a supply voltage of ±6V be enough for me? Or will this negatively affect the quality of the output signal? I want to use the lowest possible voltage to reduce the size of the capacitors and transformer secondary winding.
Thanks for comments!

I just received the title unit in its Version 3
It is really changing my way of thinking and opening my eyes
First of all being unable to make a hard boiled egg after some setting problems in Windows it seems to me that it is user friendly like few units
It also seems very accurate and the measurements very repeatable
And it is making me understand things
An example
Some time ago I bought thinking I had done a smart thing some ITT made vintage midrange domes marked on the magnet
LPKM/105/37/120 FTR
one has fs=1kHz the other fs=1.5kHz
And also the impedance at fs is quite different 😕
in a word unusable Money completely wasted
Probably the business for someone is to cannibalize old speakers of their drivers and resell them to some idiot like me
Now I am aiming for new drivers from manufacturers with a good reputation
I am Italian and fortunately in Italy we do not only have the mafia but also Faital for example
Never used again and never again vintage
Without having measured the impedance first of course 😉
It is really the case to say one small step for man, one giant leap for ginetto61
Have a good day everyone
gino

P.S. next in line mains power transformers I am sure that their impedance sweep will tell me things

I am doing a full recap of these speakers and am wondering if these will improve on the Jantzen standard Z-cap and ClarityCap PX I already have in there. Anyone familiar with this brand? I also have 47uF 100V non polar Dayton brand electrolytics in there and am wondering if replacing with 47uF film would be wise.

Greetings,
I'm a retired audio and automation engineer living in Tasmania, Australia. I've just finished building a house in a place called Seven Mile Beach and I now plan to fill it with audio equipment that I've always wanted. However, whilst they sounded good to me, visually were pretty ordinary. So I'm focussed on scratch-building replica audio equipment with my own design appearance. The nostalgia of the simpler (and analogue) times, as us oldies do. (mostly)
So currently in mid construction are: 2 x VTA valve mono amps; 1 x VTA valve preamp; 2 x Dynaco 416 power amps; Marantz 2275 receiver; Luxman 3-way active x-over; AR 3a speakers; AR LST speakers; AR XB turntable.
Good to be here.
Regards.

Hello,
I am looking for the electronic diagram of this amp or the component references (all mosfets, dual diode, C5, D32, D48 and R104.
THANKS

Hi everyone,
My name is Francisco, and I am new in this forum, hope I can learn and help in my short possibilities! (I am new in the vintage and Hifi world)
I have purchased a 1976 Technics SU7700 which seems to be in good conditions, esthetic is perfect, but once I begin to play music there are some issues I want to know if can be solved with a recap of the 36 electrolytic capacitors, (I found a Nichicon kit for this amp). The ratings of this amp in internet make me think that it should sound quite better! My problem is to know if it is a good investment to recap or it needs other major electronic reparations that could rise the money I will need to put on it.
Before testing I have cleaned all the PCB, I have changed a 500 mA fuse that protect the vumeters lamp and I have tried to lubricate/clean the volume, balance, bass and treble knobs, but I think the job done isn´t enough. Should I dissamble all the cable connections from each potentiometer and extract them from the main aluminiun front cover for clean them properly?
1) The first test have been done using a mobile phone as source, connected to AUX, TUNER, PHONO and TAPE (playback). The loudspeakers have been connected biwired to main and remote connections. The problem, apart from the poor performance, is that the R channel sound very weak, and if you turn the balance to force this channel it doesn´t get better. This happens using all the sources, unless I connect the mobile to PHONO, where it sounds higher but without good quality. In TAPE the sound has a little more power and in TUNER and AUX there isnt´t any sound in R channel. I have not tested with other source, no CD player nor tuner.
2) If I check the headphones connection now it sounds in stereo, but again, the sound quality is bad, and if the volume knob is turned, it scratches a lot. So I know it needs a good potentiometers cleaning.
3)Other problem is the noise that produces the system all the time, which can be well checked with the headphones. Maybe I need to connect the ground of the amp to the ground of the house, as the 230 V cable of the amp doesn´t have ground line? The noise depends of the position of the minijack connected to the mobile phone.
4)I have noted that in the Technics manual there is an explanation for alignment, that can be done testing with a voltimeter each channel. If the measurement is over 25 mV it needs a bridge connection to be cutted, the same process for each channel. In my amp, this bridge connection has been cutted only in one of the channels, so I think that someone did this checking before. This can be the cause of the poor performance?
5) Finally, I have noticed that the thermal paste used for the connection of the power transistors to the cooling fins is not dried, once you touch you can remove it.
Best regards and thanks !!!

I’m going to add bass extension to my 2-way speakers. The speakers consist of 1” SEAS H400 tweeters and 6.5” SEAS H602 woofers. I still have a pair of the H602 woofers unused. I think of 2 methods for the upgrade.

A) passive subwoofer
Build crossovers and enclosures for the remaining H602 and use them with the existing 2-way speakers but leave the 2-way speakers untouched—no high pass for the 2-way.

B) convert the 2-way to 2.5-way system
Add the unused H602 to the 2-way and redesign crossovers to the way 2.5-way did as shown in the picture.



Which choice is more suitable?

Hi All,

iam having an power amplifier Perreaux MC6100 all of its caps have gone bad which are of capacitance 6800uf 80v, my question is can i upgrade all the caps with 10000uf 80v elna audio grade capacitor of same size as iam unable to procure 6800uf 80v caps good Audio grade ones?

https://www.highperformancestereo.com/perreaux-6100-6-channel-amplifier.html

any pointers are much appreciated.

Thanks
Raghu

This is about the 8930B calibrator for 1/2 inch microphones. I got mine from Thoman but I see it is now also available from Aliexpress.

https://images.static-thomann.de/pi...U5NjNka1UydndISEZVYWxFNlBiSUE1SEtFZUElM0QlM0Q.

The manual says this:
Carefully insert microphone up to the stop within the calibrator cavity. The O-ring will offer some resistance.

I suppose they want to tell the user to stick the microphone in all the way to the stop. And it makes sense in that the initially cylindrical entrance hole ends in a ridge that is about 1 mm smaller in diameter. Behind that is a hollow half dome chamber. The insertion depth is about 12 mm.

I was sceptical about this because on all B&K and Norsonic capsules I have, the protection grid is somewhat wider than the capsule itself. So the O-ring seals tightly during the first 7 or so mm and feels kind of loose the moment it sits on the capsule rather than the grid. Of course, the reading gets higher when the microphone is fully inserted.

However, I just bought my first new in box sound level meter, and it displays 93.8 dB out of the box only when fully inserted.

Hi,

So I saw this image and it made me realise that I might not understand balanced, I just thought it separated the grounds so you could double the voltage and that was better for longer cables, resistance to interference and making (headphone) amps play louder (I think a power amp sort of "multiplies" sound, so say 2V x 10W is 20W then 4V x 10W is 40W I think this is probably way oversimplified).

Then it occurred to me (I was told that the analogue section of most DACs is what let them down) that a balanced DAC might have twice the (what I'll call) "bandwidth" like 4V means more "signal". I read 3dB more dynamic range. Do you get more "resolution"?

I also read some ladder DACs improve balanced, like maybe you can have more steps in your ladder?

The CamillaDSP setup in the image is using two channels on a DAC changed into one channel balanced, is that going to "measure" better?

I was also chatting about (digital) volume and that you lose headroom, do you get more headroom with balanced, I have got to admit that I don't fully understand (a lot of advanced audio stuff including) headroom.

Can someone please sum things up for me?

Thanks.

The new King of DACs is here!
For more information please see:
AKD49 series ...

Evening,
Hoping someone on this forum has some experience with Music Hall a15.3. Bought it non-working, knowing it had one channel blown. But after removing and replacing the outputs (I replaced original 2SA1186/2SC2837 with 2SA1386/2SC3519 - which seemed like an exact match but with higher voltage and amperage ratings, albeit slightly slower at 30MHz vs 60MHz). I also tested all other transistors with the DMM and they checked out good. Compared resistors, capacitors and diodes to each channel and those also checked out good.

Symptom(s) ---
Powering on the unit you can hear the two relays "click" but about 5 seconds later, you hear a third relay "click" on the input section and the front panel LEDs start blinking (tried to show in pictures below)
1) first pic is on power-up, volume control and selected input LEDs light up
2) after about 5 seconds from relays clicking in, all the front panel LEDs light up
3) all the front panel LEDs continue to flash every second until you turn the power off (powering up again, starts this process over again)

I cannot find anything wrong with either power amplifier section - both have about 15mV of bias, pre-drivers get warm (maybe 90-degree F) but nothing too hot to touch comfortably. I also get 12mV and 9mV DC on the outputs - so it doesn't appear to be amplifier related due to protection kicking in.

I get all the low voltages as listed on the board +/-45V, +/-15V, +5V and +9V. Gone through the entire board checking resistors, diodes and capacitors and I have not found anything out of spec. (anything suspect, has been removed and tested out of circuit - with all testing good and soldered back in)

Anything you could suggest I try, or might know as a problem on these integrated amplifiers? I have had this sitting around for 2-3 months, working on it off and on - generally getting frustrated because I can't seem to find a faulty part.

Could it be one of the input "chips" or maybe the front panel "chip"? Not the best at reading a datasheet and circuit design and knowing how to confirm if it's working. I did check all the resistors and capacitors on the front panel and they seem in good working order and all measurements seem logical.

Could not find a schematic, so if someone has one would appreciate you sharing it with me.

Hello

Can't find out value of this resistor...
Have tried calculators.
Dose anny one know the value?

1936 - 2024
Even if I never was a big country music follower, I knew and admired him and his music.
Rest in peace!

During my development of TDA1387-based DACs I came to the tentative conclusion that fewer chips was generally better in SQ terms. That was based on experience that strongly hinted that the power supply was the limiting factor and that more chips meant heavier demands on the supply. I also found that more output current made an I/V stage (other than a purely passive one) harder to get sounding good.

The power supply sensitivity turned out to be in large degree dependent on the variation in output voltage at the DAC's current outputs - purely passive I/V usually has the largest output voltage variation, consequently the highest sensitivity to power supply rail noise. By 'noise' here I don't just mean random noise, normally load-induced (i.e. signal correlated) noise is a bigger influencer of SQ.

A 'lightbulb' moment came when I considered that a step-up transformer could be used to ensure a very low voltage variation at the DAC's output whilst still allowing a high enough I/V resistor to be used so as not to need a voltage gain stage to create a 2VRMS output signal. Use of a step-up transformer isn't new, Audio Note had a patent on it (now expired). What is new is using a high ratio step-up transformer in conjunction with a very large number of paralleled DAC chips - the parallel array allows an even smaller variation of DAC output voltage and hence lower power supply sensitivity.

I've attached an outline sketch of the arrangement. A large number of paralleled DACs generates a peak current in the region of a few tens of mA. The DAC arrays are arranged to generate that current in 'push-pull' mode (aka 'balanced') so that there isn't any need to block the DC through the trafo - the DC currents are applied out of phase and hence cancel within the core of the trafo. The secondary of the trafo has typically 100X the turns of the primary meaning the standard 2VRMS is generated directly from 20mV at the DAC and only needs filtering (to attenuate images) and buffering to create a low output impedance for driving cables and a power- or pre- amp.

From my earliest experiments with a step-up transformer, I found that the primary inductance is what creates the LF roll-off and that the usual core material I use (PC40) doesn't give enough inductance (or have high enough mu in other words) to give an optimized design. So I have moved over to using 10K material which has about 4X higher mu but a lower peak flux capability. There aren't too many forms of core that this 10K material turns up in (at least in off-the-shelf quantities) on Taobao, I have for my earliest public design settled on using EP17. The wish to create a fully balanced design means using two EP17s per channel, for a total of 4. Fortunately they're cheap to buy on Taobao, the main cost is going to be in the labour to wind them.

Gerbers are attached for a 36 DAC board - four of these are needed to feed into the 4 EP17 transformers so that the output created is 2VRMS across the I/V resistors. In the sketch the output filter's shown single-ended but for the first design I'm going balanced, necessitating doubling up on filter and buffers, leading to a transformer between the two phases for creating a single-ended output.

I have a cab that uses a pair of 15” Fender P.S. 15Bs. They’re quite nice and from what I know they’re made by Guass. Unfortunately one of the woofers has some pretty major coil rub so it needs a recone.

I’ve done many recones in the past so confident in the ability, but I want to make sure I get the right parts. It looks to have a 4” coil. I did some looking and I don’t know, can anyone point out the parts they’d use to rebuild this?


Thank you,
Dan

https://audioxpress.com/article/fre...audio-imm-6c-usb-c-calibrated-test-microphone



dave

I just bought a new DATS V3.
After Test Leads Calibration and Impedance Calibration (with integrated 1k resistor) there is a small increase of the value of the Test Leads resistance around 20 kHz and small decrease of the value of the integrated 1k resistor around 20 kHz (see pictures).

Is this the expected result after the completed calibration ?

Thanks in advance for any advice.

Need : which tubes are in the unit. Can see the 4x 6dj8 but besides there is a smaller one... another smaller one and a bigger one cannot see the lettering ...

Welcome to a super boring 2 way build

Well.... I have these Silver flutes laying around and decided to make a cheapo 2 way with them. They were originally meant for my car but wouldn't fit. Then I was going to throw them in the wife's car but.... also will not fit.

So screw it! Lets throw some more money into the pit in the form of a tweeter and some crossover components and see what happens.

I picked this Peerless tweeter to go with it. The built in waveguide lets me cross it quite low. Under 2k. This should, in theory, sound better that crossing it over inbetween 2-5k which, I am told, is not the best place to cross drivers since hearing is sensitive there. The waveguide puts the z offset of the tweeter mechanically close to the z offset of the woofer. I am going to test this to see how close they actually end up.

I'm going to throw a 0.4 cubic foot box at this and vent it. I will post the WinISD sim.

Just thought I'd share. I'll probably use these in my garage since both drivers have really good off axis specs.

Pretty simple, pretty boring, maybe they will sound pretty good.

I'm looking for opinions about modding any of the components on this crossover. Any recommendations on which parts and what I might replace them with would be much appreciated, thanks!

Hey guys. This is a long shot - does anyone have a schematic for this TM1000X5ad amplifier? This is a marine amp that is still being produced so Rockford won’t give out any diagrams.

It came in with Q1 and Q10 (IRFB4115) short. I removed the whole side and I moved two over from the other side to fit one in each bank. When the amp powers up, the low side has a normal looking pattern but it appears there’s about 28V leaking into it. Also, when you flip the amp over, I have two fets (IRFR4510’s) hot and their associated output inductor is getting hot as well. These fets do not appear to be marked with any associated Q’s so it’s hard to describe it. It would be the upper left two when the amp is flipped over.

I can’t tell if this is a two part problem or if it’s all related. On the top side D2012 (BAV99 or A7) has low side oscillation on pins 1 and 3 but 28V on pin 2. On the other working side it has only 8V or so.

I’m starting to get stumped on this one. I’d like to get the Q10 and Q1’s gates cleaned up - I can’t find the drive circuit for it, it’s nearly impossible to trace it with everything black and covered in marine grade coating. And I’d like to find out why the two fets on the bottom are getting hot.

I know, I know, the PCM1794A, PCM1798 and similar are wildly unfashionable at this point. That said, they're not terribly expensive, and are relatively easy to implement using hardware control. I'd like to see how much performance we can milk out of them.

Paul Frost over at the TI E2E forum shared a schematic approximating what the IREF and VCOM pins actually do. (Over here.) Here's the schematic; note that VREF1 and VCOM2 pins are not physically accessible on the chip




I've seen many projects where the IREF pin is fed by a CCS. It looks like this would more or less take the servo amp out of the equation; the CCS sets the current though the current mirror which biases the LTP CCSs which make up the output stage. This also aligns well with the projects I've read here: reducing R_IREF increases the ouput current and changes the voltage on the VCOM pin.

That said, I haven't seen any experiments where the VCOM pin is fed by an external voltage reference. I tried connecting a GLED431 reference from VCOM to VCC with a 4mA CCS from VCOM to ground. This also scales the output current, but the DAC seems to work well. There's nothing obviously wrong with the sound and measurements are comparable with to using a CCS on IREF and a large cap on VCOM (but not directly comparable as I haven't matched the levels at 0dBFS).

Would anyone have thoughts on the technical merits of either approach? I would assume that we could provide a higher quality offboard reference, but I think I'm missing some of the subtlety of the servo amp. What exactly is it servo-ing?

Hi Everyone! I'm looking to see if I can't diagnose noise occurring in a Don Sachs vacuum tube preamplifier, which is based on an Aikido preamplifier circuit also used by Tubes4Hifi in its SP14 preamplifier.

Here's the scoop.

The preamplifier uses 4 6SN7 octal tubes, has dual mono regulated power supplies for each channel, for both B+ and filaments.

The Issue:

1. Hum/buzz on left channel only; Right channel is nice and quiet.
2. On startup, the hum is barely there if at all. Within a few minutes the hum comes on and grows in volume over time.
3. Hum is not affected by: moving to different system, house, swapping new/different tubes, changing cables, removing other equipment, etc..
4. Hum is present even with no source connected.
5. Hum is present even if using power conditioners or not using them.
6. I've disconnected everything and the hum is present (so long as an amplification source and loudspeaker are present on the left channel.
7. The sound of the hum/noise oscillates a bit and sounds like a motor running and changing speed due to changes in power sent to it.
8. It has grown over time (last month) to now it has to be addressed.

I emailed Don but he's doing a new thing now (no longer building these) and I did buy this preamp used. I know he said once that he recommends putting carbon film caps on the grids and cathodes for all 6sn7s, but I haven't inspected it that closely to know.

Here's a link to the SP14 schematic:
https://www.icloud.com/iclouddrive/0c1iv9KCt0l7X80KfV0UNxpEw#Public

I will take a photo tonight of the actual PCB in Don's amp to show where there are differences.

I opened the unit just to see if there was a cold solder or disconnected ground, etc. Everything is sturdy and sound (from observation with the eye). I haven't tested anything with my multimeter and I don't have other testing equipment.

My sense is there's some DC leaking in a capacitor or a failed resistor, but I'm not sure where to start. Maybe there's a ground loop, but I'm not seeing it with a naked eye.

Any help is super appreciated. If you're in the Chicagoland, NW Indiana, or SE WI area I'd pay you to consult!

Thank you!!!!

Hello, used for low spl mesurements, perfect condition.
250€ for the two units.
Regards

I have a total of 4 Brand New AE Acoustics Elegance TD15M Midrange Woofer Drivers For Sale. I am the original owner and purchased them directly from AE Speakers many years ago for my DIY Speakers.

But I didn't have time to start the project so they are Brand New unused and in perfect factory condition.

Price is $800 each from AE Speakers currently and you can make a fair offer.

I will ship them in the U.S.A with FedEx Ground insured only.

PayPal is the Preferred payment method but you must have a confirmed shipping address.

Selling 1x pair of Tamura A-342 interstage transformers, like new

5K:5K (2.5k split), 30 ma

SOLD

Selling 1x Tamura PC-3004 power transformer, NIB

Prim : 0-100V
Sec : 400V-360V-0-120V-360V-400V (DC250mA), 6.3V-4V-0(3.6A), 6.3V-4V-0(3.6A), 5V(3.8A), 5V-4V-0(3A), 7.5V-5V-0(3A)

Including Tamradio top plate and screws

SOLD

Selling 1x pair of Tamura F-2004 SE Output transformers, in excellent condition

Prim 5K, DC 100ma / Sec 8 and 16 ohm, 8W
Prim inductance: 16H
Freq. response: 30hz-80khz

SOLD

My name is István and I want to build a planet10

My love for music began young. Before showing my non-audiophile friends my system, I tell them it's a cautionary tale of why one shouldn't let their teenager stop playing an instrument. 🙂

I've been getting into micro controllers like the ESP-32 and adding some audio and amps to them. Hoping some people here can help point me in the right direction with a few of the issues I'm having with sound quality!

Hi, I built the North Creek Okara II speaker over a decade ago to replace my Lyn Olson Ariels. I keep all the crossover components. I currently use a cheap AliExpress 2nd order crossover on the Okara II. I was hoping somebody had an original crossover schematic for the Okara so I could use the parts I have on hand. I then plan on learning how to use the Xsim software to optimise the cabinets I built, as they have a different front baffle, which I designed to look similar to one of the Sonus GFaber designs!

I am Zoli from Hungary. I like music, speakers and DIY speakers and I want to read a lot of information on the forum about the science of speaker construction.

My name is Kim. I’m an electrical engineer and an audio hobbyist. I also design, manufacture and sell vacuum tube guitar amplifiers.
I particularly enjoy modifying stereo tube amplifiers to improve their performance.

Hello, my name is Vlad, I have a lot of American old amps, dacs, etc… it’s very interesting check and repair audio of Golgen Era - not my own arms, haha.

Hi everyone, I have 2 Quad 405 Clone boards which I would like to install in an aluminum housing.


I have wired the whole thing as shown in the picture,



but I can hear a quiet hum on one channel. It is not loud and you have to get very close to the woofer to hear it, but it is audible.
I use the following switching power supply, it is a +- 40V (I know it is not 50, I will upgrade it later).

I have also tried to remove the ground loop breaker and connect PE directly to the GND of the SMPS, same behavior.
I am quite a novice when it comes to amplifier construction, so please point out the mistake.

Thanks

Hei everyone! 😊

Too long; didn't read:I’m building a website to make DIY speaker design easier with features like build plans, calculators, 3D design help, and driver selection. Launching in 2 months—what top 5 features do you need most when building speakers? Let me know!

I hope you're all doing well! 😊 I wanted to share something I'm incredibly excited about, and I would love to hear your thoughts and feedback.

As an engineer and web developer who's always had a passion for DIY projects, I've spent countless hours building speakers over the years. One thing I've always thought about while working on my own builds is how amazing it would be to have an all-in-one tool that helps guide the design and building process from start to finish. A place where I could get help with calculations, design suggestions, and even visualize my speaker in 3D before ever cutting a piece of wood.

That's why I've decided to stop dreaming and start building a website that does exactly that! 🎉

My goal is to create a platform where anyone—from complete beginners to seasoned audiophiles—can easily design and build their own speakers, all with the help of integrated tools like:

• Build plans: Step-by-step guides to take you from concept to completion.

• Speaker calculators: Automatically handle the math behind speaker enclosures and ports.

• 3D design assistance: Visualize your speaker in 3D and adjust it as you go.

• Driver selection help: Get recommendations for drivers based on your design goals.

• And more...

The ultimate goal would be to have an integration with ChatGPT or similar, so you can get guidance throughout the whole process, going from an idea to build plans automagically through a simple conversation.

I’m planning to launch the first iteration of this website in a few months! But before I dive too deep into development, I want to make sure it’s as helpful and useful as possible.

So here’s where I need your help: What are the top 5 features you wish you had (or currently need) when building your own speakers? Whether it’s a tool you’ve always wanted or a problem you regularly face, I’d love to hear it!

Your feedback will be super valuable in shaping the platform, and I’d love to build something that truly meets the needs of the DIY speaker community.

Thanks so much for your time and input—I'm genuinely thrilled to see what we can create together. Let's make speaker building easier, more fun, and more accessible for everyone! 💡🔊


Cheers, Eirik

Hi,

I'm new to a lot of the "measurement" stuff, please be gentle!

So I want to build my first XO with CamillaDSP.

So I have a RPi5/DAC8X and I think I need a way to expose all eight DAC8X channels to the calibration Windows PC?

So perhaps can the USB UAC2 gadget expose them or does it max out at 2 channels?

I'm asking because from the limited info I can find online it looks like XO stuff in Audiolense XO needs access to the individual channels.

Or do I need 8 channels of USB DAC for testing, if so, thinking out loud, could I get four cheap 2 channel USB DACs, maybe PCM5102A DAC chips same as the DAC8X, it feels like this could cause "timing" issues though?

Could I use a 2 channel DAC and manually change cables when testing say the LR tweeters when testing stereo HF or the R mid to R tweeter when testing XO?

I do have an old MiniDSP U-DAC8 8-channel, not sure if it would be a mortal sin to use that for measurement? I also have a 4 channel UMC204HD.

Or am I barking up the wrong tree, I asked on the AudioLense XO forum but no reply yet.

Thanks!

I am Dave Saty, a retired Controls Engineer who's interest is in modifying audio and home theater gear. I bought the contents of the shop I once worked at and have lots of factory service manuals from the 70's through the 90's I can share.

I am looking for a datasheet of this foil dual capacitor from the attachment:
Aerovox "EMECB00020" 4.4/6.0 µF (J) 220/160 VAC "28CR6220447JBLE"

Hi everyone !
i wanted to make a PCB ESL for a long long time, its just gone be mid/treble panel with some features to segment it later on (so divided by 3 for instance)... but i had problems with the only PCB software i know EasyEda (perfect for electronics, not for other things you can do with pcb), all pcb software is based on a schematic. parts etc and then make a pcb. i myself work in sketchup... yes old... and crap. but thats what i would like to use or something similar . any one has an idea of a piece of software where you can draw you panel (mostly holes and dictate where copper is gone be and where is not, double sides or preferred even 4 layers to encapsule the copper)
i ca import a DXF into easyeda, and make all circles a cut trough thats one step... but i want the copper not extend to the edge of the holes... and i would like if possible the copper to be embedded in layer 2 or 3.. so no painting or whatever is required.
does anyone have a idea what works simple and i can upload to JLCpcb for instance ? image is of an imported DXF in easy eda. but i dont know where to start. i dont want just holes...(i want the copper to be slightly bigger hole so it wont arc etc , and i want to make segmented parts... but not to sure how , since the PCB programs are mostly based on the schematic. instead of just drawing 🙂)

Ich habe einen Quad 405 und möchte wissen,ob ich die Leistung des PCB"s weiter drosseln kann, indem ich "R11" von 1,8K herunter setze. Kann es zu Brummen oder Klippen kommen bei halbem "R"?

Hi all, got a band that "needs" an insanely loud guitar amplifier, so I figured I would build them something in the 300w range.

I found this schematic on google, does it seem trustworthy? I am thinking this circuit and a 2 channel jfet based preamp should sound good enough considering the application.

Any thoughts or suggestions?

Are there any? I've tried looking for one but with no success. The alternative is getting two 24V power supplies and wiring them in series, but that seems awfully inefficient. (It's for a 35W@8 ohm guitar amp).

Discrete Pro Op-amps, Big selection for op-amp rolling, for use in S500 preamps and other studio equipment, which only needs one op-amp.

There is only one of each, and they are clones of different famous op-amps that have been used over time. They have different sound signatures
and overdrive characteristics.

They are only sold as a complete batch with 10 pcs., that are:

• Hairball Audio JE-990 (Jensen 990 klone),
• Five Fish DOA 12 (?),
• Five Fish DOA 17 (Melcor 1731 klone),
• Iron Age M2 (Melcor 1731 klone),
• Iron Age NV (Neve klone),
• Iron Age NDOA (Neumann clone),
• Iron Age QDOA (Quad Eight klone),
• Iron Age FDOA (Flickinger 290-3 klone),
• Iron Age ADOA (API 2590 klone) and
• Iron Age JDOA (Jensen 918 klone).

Price pre payment including transportation to an EU country: Euro 375.