Got an A88 which has been much modified. I found the previous owner had cut most of the cables in the preamp, so I stripped all of that out with the intent of using it as a straight power amplifier. However, I have run out of both expertise and time and would like an expert to give it a once over and do some basic testing. Very happy to pay for your time and ship it down to you, but I would rather get it working than scrap it. Of course, the original case is now full of holes etc where the knobs and switches once were so I am going to build a wooden case for it. If anyone wants some 88 spares, please get in touch!

I thought that posts could be edited by the poster after it has gone live? Is that functionality gone?

I se that an individual starting a new head has he capability to edit a post to show, among other things, that an item in a list of times for sale is no longer available, or a new item has been added. How do I do that?

I checked Help, and ran a search in this forum to no avail. Do I need to ask the forum administrator to make changes? If so, how would I accomplish this?

I recently parted out an old Baldwin 41P organ, and among the future amplifier parts is an OPT labeled 512-19234B. I did a ratio test at both 60 hz and 1khz, and the turns ratio is approximately 19.3 : 1. I did not think to check the speaker impedance or wiring (series or parallel) before disposing the of the unusable parts of the organ , so I have no idea what the reflected impedance would have been. Does anyone happen to know what the typical Baldwin organ speaker impedance/wiring scheme of that era would have been? My research seems to indicate that the speaker impedance may have been 16 ohms, and there were two of them powered by the 2-tube PP 6L6 amplifier section from which this transformer came. I also would like to know if a 6V6 PP power section would handle roughly 3K impedance on the primary from an 8-ohm secondary load. Thanks for any help anyone can provide!

PS, I did find this post about the same transformer (https://www.diyaudio.com/community/threads/baldwin-transformer-swap.168380/#post-2213258). It gives 6.4K to 8 as the impedance ratio which works out to a 28:1 turns ratio if my math is correct (square root of the impedance ratio 6.4k/8), but that doesn't match what I'm measuring out of my 512-19234B unit. Hmmmmm.....

Have one of these in the shop. Customer had brought to another shop prior to bringing here.
The problem I noted off the get-go was that the front panel LED doesn't light at all and the amplifier won't pass any signal and appears to be in mute.

Taking a closer look at this front end PCB, it looks like Q1, Q2, Q4 and Q5 were removed for some reason.
The PIC doesn't have any observable clock on pin 1. I don't know if the PIC is bad, or if the board doesn't work because of the missing transistors.

If anyone is familiar with this particular VTL preamp, can you tell me if these transistors are present on other serial number units?

Hello folks,
I have a Philips CD100 CD Player I purchased back in 1983 in Belgium.
I moved to Florida 37 years ago and I would like to fire it up again, but I need help with the Voltage selection.
There is no external switch selector I can use so it has to be done internally.

I've done some reasearch and I translated some instructions using Google translate.
Unfortunately it still not clear enough and my brains cannot figure this out, so maybe someone can chime in.

I'm including a couple pictures.

Thanks.

Its a recording of a set of mine using CBT like ribbon drivers (yes with shading) and a pair of my old planar bass panels.
i bought some new mics and wanted to see if this pair finally works out. put your headphones on!! and have patience i talk allot 🙂

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Hi,

In a project I'm working on I need a source follower supplied with +40 and -140V, with a cascode of two BJT as CCS set at 6 mA.
The bottom BJT will be a 2N5551, while I'm open to suggestion for the top BJT.
Requirements are:

1. Being able to dissipate up to 900mW on peaks (it will swing up to +10V), 450mW as average (it will be set around -55V at idle), so I would say we need to exclude TO92;
2. Vce of at least 200V (I'd consider at least 230V for safety due to voltage fluctuations on the 180V we have as nominal);
3. Fit a classic TO92 pcb connection (1=b 2=c 3=e) because this is how the pcb has been done;
4. A good Hfe to improve the CCS impedance.

I've checked on mouser, and I've found some options:

1. KSC2752Y : https://www.mouser.it/datasheet/2/308/1/KSC2752_D-1810664.pdf
   TO126, Vce 300V, Hfe 40-80, pinout fits, 0.61 €/each;
2. TTC011B : https://www.mouser.it/datasheet/2/408/TTC011B_datasheet_en_20160209-1649840.pdf
   TO126, Vce 200V, Hfe 100-320, pinout fits, 0.64 €/each;
3. TTC008 : https://www.mouser.it/datasheet/2/408/TTC008_datasheet_en_20140403-1916100.pdf
   New PW-Mold2, Vce 200V, Hfe 80-250, pinout fits, 0.87 €/each;
4. TTD1409B : https://www.mouser.it/datasheet/2/408/TTD1409B_datasheet_en_20150806-1915948.pdf
   TO126, Vce 400V, Hfe 600, pinout fits, 1.62 €/each.

TTD1409B seems the best choice, do you have other suggestions?
Thanks in advance,

Kind Regards
Roberto

A Gift option has appeared under messages. It appears to buy membership time for the recipient. I had not seen an announcement of this interesting feature?

I just changed the grid resistor value from 500r to 2k on a 12b4a preamp build.
I now have to advance the volume pot significantly to reach a normal listening volume.
I have never made such a large change in grid resistor on any project...
Is this to be expected?

Hello everyone,
is anyone able to view these images?

[/URL].

[/URL].

They are diagrams published on this forum, but I cannot open them.
I thank those who can help me in advance.

Wondering if anyone in this forum can offer guidance on a minor issue with my Unison Research S6 tube integrated amplifier. This amp has six buttons to adjust the bias - one for each EL34 power tube. There is one "bias meter" per channel and each meter has three buttons associated with it - one for each EL34 tube (six in total).

The issue is that the meter does not react when pressing the top left bias adjuster button. There are no issues with the other buttons. I have tried switching the afftected tube with a different functional EL34 tube but I'm still not getting a meter response - ie - meter needle does not react.

I may be wrong but in my newbie opinion, the tube and its power output do not seem to be affected. The tube glows as usual and there is no audible difference.

Anyone have any ideas of what can be wrong? Anyone believe this is serious enough for me to stop turning on the amp until it's fixed?

Thanks in advance for any response and guidance.
Tony

I write a post on my phone, using brave browser, copy a link, select text in the post, click on the link button in the post toolbar, paste the link, and the post is 'sent' as well as the link being added to the post...

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So the setup in no particular order;

• DAC is silent, scope is on the left channel, DAC is connected to a 10KOhm line in.
• "Default" the scope
• Auto tune
• Set time division really wide to allow analysis of lower freqs (1 per division 14Mpts in my case)
• Math->FFT
• Exclusive screen
• Units dbm
• Horizontal reference and Hz per division set to show 0-22k (35k actually).
• Label peaks, show table, show frequency.

I don't see any 50Hz, unless that unlabeled peak is it? However its more likely to be FFT bin 0 aka DC.

Not shown is the rest of the spectrum, which has two very obvious spikes way up to -20dbm of ~3Mhz and exactly 24.576Mhz. No surprises where they come from.

Odd thing is, this is post "filter". Although it is a "filterless" DAC in that it require no output filter. It isn't doing a very good job of cleaning all the Mhz crap out of there. Not that I will hear it, it's just it isn't necessary to be there and might upset things down stream. Besides, routing 24.576Mhz around on audio cables won't do your EMI environment much good.

Hi guys recently my mtx 2300 starts playing very low. When i bought it i replace the 16 mosfets, it was like three years ago. Didnt replace power supply transistors nor rectifiers. Amp was playing great and one day and the next day when i turn it on, the amp starts playing very low. When new it came with ssp45n20a and i replace for the same models on the outputs. On the power supply it has 75339P. Any suggestions on where to start, no fuse blowns.

Does anyone have any info on this active crossover? I picked one up on the bay and wondering what the crossover point is (the X-1 is a 2 way).

I would open it up but I do not yet have it in my possession...was planning on sending tone thru it to try to determine the crossover point...need around 250hz for my Magnepans...

Anyone familiar with it?

When connecting a single ended source, you often see that the single ended hot line is connected to the balanced hot line (XLR pin 2), and the ground of the singe endsed source is then connected both to the cold line of the balanced input (XLR pin 3) as well as to the ground of the balanced input (XLR pin 1).
ground at the receiver end.

I believe this last connection, to receiver ground, is not required (assuming you have enough headroom), but I'm not sure.

What do ye think?

Jan

Hello together,
I am currently building the Troels Gravensen Illuminator 5 and except the 12 MU I already got all drivers. I am interested in the 4 as well as the 8 Ohm version.
I live in Germany and therefore I prefer offers from Europe as VAT is expensive. Just PM me and tell me your price.
Greetings Björn

Can anyone recommend a good solder for me. Looking at some of the usual brands it seems hard to find a dealer in the UK for leaded solder. Everything on the likes of amazonUK seems to be lead free?

Speaker Builders Dream SALE!!!

The majority of these items are new. Those which are not are in mint brand new condition.

Beyma 15P80FE/N 15" Woofer Pair:
https://www.ebay.com/itm/275641135898

B&C DCM 414 Compression Driver Pair:
https://www.ebay.com/itm/275594401096

Beyma CP755ND Compression Driver Single:
https://www.ebay.com/itm/275594358408

Beyma CP380M Compression Driver Pair:
https://www.ebay.com/itm/275594360760

Well duh, isn't that what room correction systems are SUPPOSED to do?!?! However nothing in this world is perfect. And the idea of this thread is not to focus on the lowest frequencies. (Nor to answer by saying "use active crossovers or DSP**)

• My big question really is can Audyssey/Dirac/ARC fix the drooping response of a constant directivity horn?*
• Baffle step compensation, instead of bothering about this (which is then bothered by room boundary proximities anyway) can room correction "fix" it?
• If the correction system is allegedly time-based, can it correct time misalignment between drivers?

Any other observations about limitations-or little known strengths-of such systems please post!


*I have a bucket list dream to make some high sensitivity PA-style woofer + big horn towers. I would like constant directivity, which then means the response drooping at ah isn't it -6 dB per octave IIRC?

• I did ask this question to Audyssey but the answer was equivocal and not specific.
• The amount of boost/cut needed for a big horn could add up considerably, no?

**So far the only painless way to do surround is an AVR or pre-pro. I haven't seen for instance a pre-pro box with multiple digital out. I'm aware some folks implement home theater PCs but I will never get around to such in this lifetime.

Sale:
6P14P-EV - 500 pcs. for $10,
6P14P-ER - 100 pcs. for $12,
6N23P-EV - 100 pcs. for $20,
6N13S - 100 pcs. for $7.

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I rewatched this last night and thought that some of you would appreciate it. Fantastic sit down with Ralph, Chester, Terry, Chad, and Ruth. I think that I have a bit of a mind crush on Ruth. Glenn.

Hey all. I've fantasized for a while about building a bass tower to go with my HiVi 3.1's. The L6-6R is so cheap and I really quite like it's cousin, the L6-4R, which is already in the bookshelves. The goal is not to create a subwoofer, or necessarily modify my existing bookshelves, which are DSP corrected. It is to increase the headroom and bass output by essentially converting it to a 3.5-way with a null in the rear. I may have to plug the bookshelf's port to do this. I don't know yet. For simplicity's sake, I'm simulating a baffle and a sealed enclosure, but not using any sort of measurements. Again-- purely theoretical.

This all started when I saw a great video on bass and airflow on Youtube. I highly recommend it if vents, cardioid setups, or just bass in general is a bit mystifying.
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I read a few articles on cardioid subwoofers and how to set them up. It's easier than I thought. Essentially you create a delay so the out-of-phase wave created by the rear speaker is arriving at the same time as the forward in-phase speaker. This negative pressure also creates a null behind the speaker, canceling noise near the rear speaker's source. This doesn't require as much energy as producing the actual original sound wave, so the out-of-phase rear speakers also play at reduced volume. I wonder if having all six drivers in the same enclosure would be better or worse than subdividing them individually. Maybe I'll find out if I build them!


I'd be happy to take any critiques or suggestions. I don't really know what's going on with the group delay or that resonance. In fact, I'm not sure if VituixCAD can appropriately demonstrate a cardioid setup. And yet, here it is. A heart in a polar response.

Hello!
My CD player has ADA4062 there, can I replace it with OPA2134? Does OPA2134 direct replacement of ADA4062?

Thanks!

I have for sale my Audio-gd R2R DAC. I have owned the DAC for about 2 years. It is in excellent condition and works perfectly.It has optical, coaxial and USB digital inputs.

I have been completely satisfied with it. I plan on purchasing a similar Audio-gd dac/preamp combo.
I haven't played with the jumpers to change from 8x oversampling, or 4x OS, or 2x OS or NOS or all can be bypassed I believe.

The jumpers, USB cord and power cord are included.

???响

above is a link to the audio-gd description

Original price was $680 excluding shipping.

$375.00 shipped.

I am doing some experimentation on winding my own OPTs using microwave oven iron. I previously posted a thread on that topic in general, but this is more of a specific question. I would like to attempt to use the 6AS7/6080 in SE as a headphone amp. Not OTL. I've thrown a design together that is running at 120v/plate @ 75mA into a 125:32 ohm OPT. I gather that the 6AS7 has a low Z-OUT, but how low is too low to wind the OPT, y'know? I'm feeding it with a basic 6DJ8 gain stage with 235v B+ and a 10k plate resistor. ~8mA. This is in no way a final design. It's just how everything kind-of fell into place.

It sounds good to me (maybe I'm just not picky...dunno) but I'm curious what a "good" operating point for that 6AS7 would be. I'm getting better with curves, but it's still a little hazy. I saw another post here on DIYAudio where someone was running one way up at 375v B+. ( https://www.diyaudio.com/community/threads/6as7g-se-output-stage-operating-point.383207 ) I don't mean to second guess those that are more knowledgeable than I, but is that not crazy high for this tube? I don't need a huge amount of extra gain. There is already more than enough where I'm at. I just want it to be all that it can be in my scenario.

Most any B+/Z-OUT is achievable within reason. I've gotten better at winding custom transformers. Just kinda winging it with the interleaving pattern, but I've brought down ringing and distortion. Separating each and every layer with paper tape and keeping the turns absolutely neat/straight has been the key for me. I've honestly been very pleased with the level of performance that I've gotten out of what is basically scrap iron. Performance is nearly identical to similar commercial OPTs that I have on hand at this point. I am fortunate enough to have a large cache of old microwave iron to pull from. Might as well make use of it, right? I've also wound several power transformers. Have to interleave the laminations for that, but that's not a big deal. They work great.

I have several TDA1541A ICs lying around that I do not need. These come from a job lot of parts from a closed down repair shop and have been in my storage app. 8-10 years, so I have no reason to believe they are not genuine and in perfect order.

They are confirmed by at least one person in this thread to be the real deal 🙂
https://www.diyaudio.com/community/threads/is-this-a-real-tda1541a.32587/page-37#post-7242163

I'm not giving them away, but if anyone wants to actually make use of them then make me a fair offer (on one or more of them) as I'll definitely not need all of them.

I'm located in the EU, but will of course post anywhere in the world as long as you cover the costs.

For months I've been on the lookout for a good, well-ventilated enclosure to house the JLH headphone amp, which is Class A, has board-mounted heatsinks on both sides, and runs pretty hot. Most project boxes have zero ventilation and are unusable.

I recently discovered Cheval makes a series of electronic enclosures which are well thought out and executed, with excellent cooling vents. They're made in various footprints and heights. For the JLH-HP amp I got this one :

https://www.amazon.com/Electronic-Enclosure-Case-Full-Aluminum/dp/B09MK1Z7K7/ref=sr_1_13_sspa

and it is excellent. Two adjustable board-mounting rails make pcb support easy. Once assembled, the top and bottom can be easily removed for mods/service.

The only drawback I've found is that the painted panels and anodized screws don't make for good continuity between them, so chassis grounding for shielding needs to be addressed. Scraping away a little paint around the side screw holes and using uncoated beveled flat-top screws solves the problem for the sides, top, and bottom. The front and back will need to be connected separately.

Check them out. These enclosures are reasonably priced and readily available.

Hi everyone,

I am currently working on an op amp buffer (based on the MCP6292 op amp), which must be powered from the Raspberry pi 5V GPIO.

The op amp works as expected, but I am facing some issues :
1 - When I plug everything (Audio IN from Guitar and Audio OUT to amp), no noise can be heard.
2 - When I plug everything and I play a note on my guitar, the sound out to the amp with "switching-noise".

Actually, when I play a note on my guitar, I can hear the Green activity LED blinking on the raspberry pi.

For my point of view, this is definitely a coupling issue, but I can't figure out where this happens.

I attach the schematic I use.

Could someone help me to find issue on my schematic?
I really appreciate.

Thank you.
Marius

I was recently gifted a pair of Heathkit W-5M amps and am getting ready to do a to the chassis strip down and rebuild. Since I'm going this approach, I'd like to also replace the tube sockets in addition to bringing in current quality caps and resistors. Suggestions on sources for reliable ceramic sockets would be most welcome. Thanks!

I'm about to do a build using the Beyma TPL-150 in a WMTMW (not the "H" version, mine doesn't have the waveguide). The tweeter will end up between 2 Scanspeak 18M mids. I've never worked with this Beyma, but I have heard it in a few different builds and generally always enjoyed it. Reviews are all over the place but mostly positive.

Not that I'm trolling or looking to start an argument, more of a good debate if there is one, I'm hoping to get a couple differing opinions here. "Word on the street is" the Beyma will cross as low as 1.2khz, but from what I've read the general consensus is that while the Beyma will play that low, it's best from 2khz up. Is this everyone here's opinion as well? I have a lot of wiggle room using the 18M, I think I can go up to 2.3khz without too much issue.

So, have you used this tweeter? If so, what are your thoughts? Where'd you cross it?

Also, I think the flat face of this tweeter is kinda ugly. An idea I have would be easy to measure, but to try to save me some time I'll ask... I was considering making a 1/2" thick "cover" for the Beyma and trying some different edge treatments on the opening. For example, cut a 1/2" thick piece of MDF, cut an opening (about the size of the tweeter opening in the original faceplate), and use that to "sandwich" the tweeter to the front baffle. This seems fairly simple to do, but I'm curious where I would or should start with either a roundover or a bevel on the actual opening of the tweeter (1/2" R/O, 45 degree bevel, 3/4" R/O..?). And also, is this a bad idea and a waste of time or something I should even try? (Edit) To simplify this question, do you guys think doing this would introduce too much edge diffraction? Not looking to improve performance, just make it look better.

FWIW this will be passive.

As the title says: The quote button is missing in the last post of a thread. This is happening on a mobile device.

So creating a BT sink for a digital audio system turned out to be very easy.

However it seems that creating a BT source is a lot more difficult. It took me a while until the penny dropped that of course the difference in a BT source compared to a sink, is that the source is usually the master. So it's the sources job to discover the sink and connect to it. Headphones/headsets and BT speakers typically don't have text based UIs and discovery functionality.

This is why you don't find many BT Transmitter type modules out there.

Of course they exist in IC/SoC/daughterboard form. The discovery and paring processes and the textual feedback is handled over the UART console, either by hand or from automation..

This gives me what I need, a way to connect a custom digital audio circuit to a pair of "known" headphones. In that it will be discovering periodically and if it see a pair of "my" headphones it will connect.

It leaves me to pick one and I'm going to start with a FEasyCom module as it's cheap.

However, the reason I'm posting is it got me thinking. There is more to this A2DP protocol surely. Advanced audio distribution. Hmmm. I thought about this when I walked out of reception range of my wireless headphones as I went downstairs and pondered ... can't I just create a repeater? Does BT and A2DP not support roaming of any kind?

So in short... can you use BT sources and sinks in a way to create a distribution network such that wireless headsets work across the whole house? Maybe I don't even need that if the master has a proper SMA antenna it might reach downstairs.

Anyone played around with the more advanced side of BT? Surely some of the home theatre guys using it for remote speakers and people running house wide audio. Have you explored the more advanced side of BT?

Hi guys, I wired up my 100as2 icepower board for single ended use, and it's fine off my laptop or phone, but as soon as they get plugged into power then I get hum, which I assume is a ground loop. And I get a hum from any mains powered source.

The manual says a bit about curing ground loops, but it assumes I'm using a front end PCB, which I'm not. Should I just be attaching the negative signal pin to ground in this case? And should it be GND or AGND (which has a 22ohm resistance to the general ground)?

Here's the relevant bits of the manual.

Thanks in advance, Tim 🙂

looking to build super small speakers. wanted to see if any one could recommend
4" - 5" drivers. ideally 4.

volume for each speaker will be around .1 cubic feet or 2.5-2.8 Liters

i found some by peerless and dayton audio

https://www.parts-express.com/Peerless-830870-4-PPB-Cone-HDS-Woofer-264-1070?quantity=1

https://www.parts-express.com/Dayto...-Cone-Midbass-Woofer-4-Ohm-295-415?quantity=1

https://www.parts-express.com/Peerless-BC25SC55-04-1-Square-Frame-Tweeter-264-1024?quantity=1
https://www.parts-express.com/Dayton-Audio-ND25FA-4-1-Soft-Dome-Neodymium-Tweeter-275-059?quantity=1

should i chose all 4ohm and 8 ohm drivers. most cross overs are either all 4ohm drivers or all 8ohm

ideally looking for clean beautiful midrange in sealed enclosure..
but might be tempted to go in super bass from tiny box direction

if i chose 8 ohm woofer and 4 ohm tweeter will it be a cross over design project to build cross overs or a 2 way cross over can be easily tweaked to accommodate difference in driver impedances

Have you ever had in your life a toroidal transformer Class AB amp (all in one box) with noise below -110 dB, 50/60 Hz hum? I think that's technically impossible. There are manufacturers who use switching power supplies to get around this. Does a change in the design philosophy have to take place here?

https://www.audiosciencereview.com/forum/index.php?threads/rotel-rb-1070-amplifier-review.41193/
https://www.audiosciencereview.com/...-and-measurements-of-benchmark-ahb2-amp.7628/

Hello all,

A friend and myself want to build the rev.7 of the soekris dam1021, but there is not much option to get proper control for it, with screen and remote. So we are in discussion to build a board that include everything we need.
Thanks to Dimdim there is arduino code for a small oled panel that offer volume / source / filter controls. There was a GB here for this board, but it's long gone and Dimdim do not answer my solicitation.
Before continue i want to be clear that the goal of this topic is to judge interest on this, to see if a GB is possible and how many people are interested. My friend is a professionals electronics that is doing this on his free time, and he doesn't have much of it. So there is no warranty.

What we want to do :

• We target a small size case, i want Takachi uc20-5-14DD
• Arduino Nano with Oled Screen, isolated
• External PSU block / wall mount (meanwell)
• Ldovr external Low noise reg, lt3045/3097 in +-9v for the DAC, and probably another one in 5v for the usb board.
• JLsounds usb board connector plus SPDIF/Toslink. We hesitate between JLsounds pinout and Amanero pinout, because JLsounds has his board with Amanero compatible size and pinout.
• I want space on the PCB to use the universal buffer by neurochrome. Plus a jumper if you don't want to use it and use the integrated opa1678 buffer instead.
• An On/off switch control by the arduino.
• I don't know if we'll keep it fully balanced or keep using a single ended rca connectors. Space is limited, so please tell me.
• There is a discussion to integrate a usb to rs232 adapter, for easy firmware / filter upload.

Of course every suggestion is welcome.

Regards

I have a pair of old Sony Speakers on my desktop. I've tried other speakers but unfortunately I like the sound of these. Because I live in an apartment the speakers are dually tasked to work as satellites but still sound decent at night without the sub. My one criticism is they can sound boxy when pushed.
It could be down to my inexperience or maybe its just stupidity but if the manual shows they can be disassembled - it should be possible, right?
I've tried gently prizing everywhere but I'm afraid I'm going to break them.

Any tips?

The right heatsinks of my X250 are much cooler than the left heatsinks. The front meter's position at around 11AM. Can some one advise me how to check/adjust bias and offset? Photo inside my X250 below. Many thanks 🙂

Does anyone know if there's an LTSpice simulation for a the LT3042 or LT3045?

I am trying to simulate it to regulate from 20v to 15-18v, but I am not familiar with the resistor values you need to use to set the output voltage.

When I input 20v I can't get the simulation to end.

I have spent months trying to get my chip amp to sound better.
Been doing a lot of reading. When I cam across this sentence.
Measure weather the positive and negative output voltages are symetrical.
They should be within 0.6 V of each other. This test is done under zero load.
So I tested all the transformers I have. Some EI some toro all have more than 0.6v variation on the output.
Maybe they just make shitty transformers in my country.
Another friend told me it does not matter what the difference is. It just means that one side will clip sooner than the other when pushed to the limits.
Other than trying to import a transformer how do I fix this. Do I need to worry about it ?.
I have tested direct output from the transformer and also after the voltage is passed thru the PSU board.
This pertains to my tda7294 and lm3886 builds.

Hi,
as of today it is not possible to reply directly to a post; it's possible to quote, but since not all users allow it (it's obviously possible to disallow citing), it might be tedious to put some answers in context. Quoting was automatic with the reply function.

Cheers

I have for sale the following evaluation boards from Tripath.
All evaluation boards include the the cables and plugs, power
supplies are for the power section.
RB-TK2350-80€
EB-TA0103-110€
RB-TA0105-140€
Payment by Paypal shipment for Europanean Union
For more information PM

Hi and best wishes for 2023 !
Whilst putting the finishing touches to fixing a Hypex NC122MP amp in an aluminium enclosure, I accidently shorted the Vaux positive auxiliary supply (pin J6.1): there was a hiss in the speakers and the amp went dead - that moment when you want to reverse time by 5 seconds and replay without the silly oversight 🙁

After 30 min off mains, and checking that the SMPS shrinkwraped mains fuse is not blown (tested for continuity), feeding mains again to the board brings the standby SMPS J6.3 pin to nominal 5V, and after asserting the J6.9 PS Enable pin, the Vaux negative auxiliary supply (pin J6.2) is nominal -20V, but the Vaux positive auxiliary supply (pin J6.1) is around 500mV instead of 20V, and the board does not drive speakers when fed audio signal. The J6.7 DC error pin isn't activated.

Visual inspection of the top part of the board does not show any signs of arcs or blown components, however removing the bottom heatsink plate shows at least one obvious blown L15 SMD component (pictures attached).

I don't have the schematics for the PCB, would anyone be able to put me on the right track to determine what that component value might be ? This L15 is one of those SMD's with no markings that I can see. Maybe there's a way to guess from a measurement of an equivalent component on the Vaux negative line (say L16 for instance), as there might by some symetry involved asks the newby naively ?

As can probably be guessed I am a just a hobbyist but at ease with DIY, equiped with a Voltcraft VC830 multimeter, a very fine tipped soldering iron, and the will to make good my f***k up however much effort I need to put into it 🙂 If need be, I can access hot air gun and more advanced measuring instruments.

Many thanks in advance for your help !
Cheers,
Pascal

Ken Block just died yesterday 2nd of January from a snowmobile accident.
"The sheriff's office in Utah said that Block had been riding with a group but was alone when the crash occurred."

He definitely lived life in the fast lane.
Surprised it happened so soon at only 55, sad to say not surprised it was involving a motorized vehicle.

Heartfelt sympathies to his wife and three children.

Hi,
I wanted to make hdmi-i2s output from project ds cd player with StreamUnlimited cd80 board.
I bought i2s to hdmi board.
I conected 5pin ribbon to folowing points. Marked with red dots on schematic and red points on board.
I measured signal with scope and was present. not so great on output as input but present.
But no lock trought hdmi i2s input on smsl m400dac. I tried dac before on computer with pinkfaud i2s hdmi card and dac was playing ok.
I2s to hdmi card has also SDA and SCL pins which were not connected.
Any idea what can be the reason?

Hi,

Because the standard "wall wart" power supply of my Cambridge Audio DacMagic power supply hummed like crazy
(as did the replacement one they sent me), I ended up making my own, using a tranformer from a Goko RM-5000 8mm recording editor from the 70s (made in Japan, it looked well built, and provides the 12V AC the DAC needs):



Recently I noticed the transformer started humming (it always was dead quiet): is it going bad and should I replace it?

with this one for example?
https://www.distrelec.nl/en/ring-core-transformer-60va-2x-12-vac-5a-noratel-aa-98029/p/15613419

(at the back of the DAC it says 12V AC, 1500 mA)

I'm thinking my setup is sounding duller than it used to, but that can be my imagination 🙄

Thanks for any input 👍

Does someone has the schematics of the Helix HXA400 MKII.
Thanks!

Give me Roman concrete.

https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106

I plan on replacing the old and tired amps on a pair of Mackie SRM450 powered speakers with a 1000asp in each speaker. Looking to add a sensitivity control (pre-amp?) and a clip light. Any thoughts on how to add these in?

Does anyone know do they make zeners in a TO220 package? Trying to replace some 5W zeners that are running hot enough to brown the board below. All I can find is up to 5W in a normal through hole package and then they start going to some type of stud design. How about any type of heatsink for the standard package.

SOLD

Asking $250 including US shipping.






I would like to try to sell this as one lot, but if no takers in a week, I will likely break it into subset sales.

These are parts that are left from various projects, and perhaps others can use them. There are some discontinued and hard to get mosfets and bjts, numerous film caps for tube and ss amps, and a number of various electrolytic caps.

LARGE MOSFETS AND BJTS
TO-247 size
(2) IRFP 9140 n channel mosfet
(3) IRFP 150 n channel mosfet
TO-3P size:
(10) FQA 9P25 p channel mosfet
TO-220 size
(10) IXTP 08N100D2 N channel mosfet
(2) DN2535 N5-G n channel mosfet
(4) IRFP 510 n channel mosfet
(12) STF 3LN 80K5 n channel mosfet
(12) IRF 610 n channel mosfet
(6) IRF 9510 P channel mosfet
(6) D45H11 PNP bjt

SMALLER FORMAT FETS AND BJTs
SMD

(10) 2SK2145gr

(100) 2SK209gr

(8) BSH111 bkr


TO-92


(19) BSS 129


(2) DN2535N3-G


(4) J112


(2) BC546a


(8) BC63916


(6)BC 546bta


(2)KSC1845


(14)ZTX550


(9)BC640ta


(20)BC556bta


(6) KSA992 fbu



TO-126-3


(4)KSC2690 ays


(6)KSA1220a



SILMIC II CAPACITORS

(2) 1000uf 6.3v


(6) 1000uf 25v


(1) 1000uf 35v


(4) 10uf 50v


(4) 22uf 50v


(5) 47uf 25v


CERAMIC / MICA CAPACITIORS

Mica


(3) 5pf 500v


(6) 10pf 500v


(1) 100pf 500v


(4) 200pf 500v


(1) 220pf 500v


(4) 420pf 500v


(2) 500pf 500v


(3) 680pf 500v

Ceramic


(2) 390pf 1 kv


(2) 2000pf 6kv


(5) .1 uf 50v x7r


(10) 1uf 50v x7r


(2) 2.2uf 50v x7r






AXIAL ELECTROLYTICS (TUBE AMP)





(3) 25uf 50v Sprague Atom


(2) 22uf 500v F&T


(2) 22uf 400v Nichicon VX(M)


(2) 16uf 475v F&T

1. 47uf 500v F&T
2. 10uf 100v Nichicon VX(M)

RADIAL ELECTROLYTIC, TUBE AMP


(1) 250uf 500v JJ


(8) 100uf 450v Nichicon GU(M)


(2) 100uf 450v Nichicon KV9M) snapcap


(1) 47uf 450v Nichicon CY(M)


(1) 10uf 450v panasonic CEEB


(2) 10uf 200v Nichicon CS(M)


(1) 22uf 450v Panasonic CEEB


(1) 22uf 450v Nichicon CY(M)


(1) 56uf 450v Nichocon KX(M)



ELECTROLYTIC CAPS, SS AMP TYPE


(2) 47uf 10v Nichicon


(1) 100uf 10v Nichicon


(4) 220uf 10v Nichicon Muse Nonpolar


(6) 15,000uf 16v Nichicon VZ(M)


(4) 15,000uf 35v Nichicon GY(M) snapcap


(1) 1,000uf 35v Wurth


(4) 220uf 50v Nichicon Muse


(4) 10uf 50v Nichicon Muse Nonpolar


(2) 220uf 50v Nichicon


(3) 470uf 63v Panasonic CEEB


(4) 1000uf 63v Nichicon VR(M)

(2) 100uf 35v Nichicon VX(M)



FILM CAPS


CDE 940 Axial


(2) 10,000pf 3kV


(2) .22uf 600vdc


(4) .22uf 2kV


(1) 1uf 1kV


Radial, mostly panasonic type


(10) .1uf 630v


(2) .1uf 1000v


(4) .22uf 630v


(6) .22uf 100v


(4) .33uf 630v


(2) .68uf 250v


(2) 1 uf 100v


(2) 680pf 63v


(2) .47uf 63v


(8) 10,000pf 100v (zobel)


(8) .15uf 100v (zobel)


(2) 1 uf 520v



Wima Caps


(4) .01uf 100v


(4) .01uf 1 kV


(4) 1uf 63v


(3) .47uf 400v


(2) 1uf 400v


Guitar Amp type caps



(4) .1uf 600v 716P orange drop


(6) .1uf 630v Illinois axial caps

I had try some 6u8a, 6gh8a, 6an8 tubes as phono preamp, I had around 10 tubes most are 6gh8a,

I build a phono preamp ciruit and found out very hard to match a pair of tube for good gain balance for L/R channel. I used the pentode and triode on the same tube.
I give up on the experiment as I don't had to much tubes to match. I think what is the
other way to take care this issued. Then I try just to match the gain on the pentode section only of each tube, I can get few match pair
I build the phono preamp again with 6gh8a pentode follow by a half 12au7, and use the 6gh8a triode as a cathode follower and the result looks good.
I had test 12au7, 12at7, 12ax7 for the triode section, all those tube works, only with different gain. I think the circuit will works with all 12xx7 tubes.

During our all out RV remodel that will have a great audio system, as much DIY as possible, I am using a 4 year old HP Laptop, USB to E30 Topping DAC on battery power, Martin Logan Vision X sound bar and it is actually quite a decent setup considering $395 into the SB and E30 and battery plus cables🙂

I am a lifelong DIY guy with considerable experience as an electronic tech and some on DIY audio, not an engineer, and know well of the snake oil levels in this great hobby. I have done DIY cables for a very long time, cheap and great and some tested against very high end cables that did not do as well in tests, including blind listening and using super high end test gear, aerospace lab grade .

This is about all the "dirty" computer USB output I keep hearing about yet not hearing in my little temp system. I just received two new batteries for the laptop, original died, so going to do some listening with and without running on battery power.

I use Qobuz for streaming and will build or buy a streamer like the Zen, etc, if I must but for now just not sure really needed so asking here as I know there are many far more advanced into this topic than I am, please help
Note, I will likely be looking more into DSP, etc though I prefer the simplest analog system I can make work.

Thanks,
Rick

SOLD


Asking $25 including US shipping

For sale is a group of power mosfets. Matched by 3 different individuals but all have worked well in other application.s

Matched sextet of IRF240 mosfets

14 IRF9240 mosfets, which is one lightly used pair, another pair accompanying the 240s, and a packet of closely matched 10.

So, overall, 20 mosfets in this sale.

SOLD

Asking just the cost of shipping, $6, to pass these on to the next owner.

I will not be using these and would like to pass them on to the next owner who can use them in an F3, etc.

https://www.diyaudio.com/community/threads/lovoltech-lu1014-power-jfet-group-buy.371283/​

Includes the 4 jfets, 4 of xrk soldering boards, connectors and grid resistors.

Good morning!
I'm trying to tame a very obnoxious issue with an old Gibson Falcon amp. The arrangement of the reverb circuit is inherently noisy; with the effect turned on we are applying 100% of the recovery circuit into the preamp. Can anyone shed any light on the idea of moving the reverb volume control from the input of the reverb system to the output, just before the 680K grid stopper of the preamp? Looks more like a deluxe reverb that way.

Thanks!

Hi,
Is it possible to change my username to OneManDIY ?

I think I am ready to move away from the gravedigger moniker 😀

Hi!
I would appreciate any help checking my design/recommendations for alternate designs if these are just unworkable.

https://www.parts-express.com/30-Wa...ackage-with-2-1-2-Full-Range-Drivers-300-7304

Edit:

BLUF: Trying to get the best use of the PC68-4 driver. I wanted to make a speaker, and needed Christmas gifts for two nieces and nephew, so it needed to be inexpensive, include the amp and bluetooth. Initially wanted three different speakers, now not so sure (but I want to try either the Cornu or an equivalent flat wall mount speaker). I don't think these amps have integral DSP to help (apparently some Dayton amps do?).

Potential bonus: if I get a decent result, maybe it helps someone else out who purchased the kit, then went looking for plans.

Plan to separate the amps and make passive speakers so they can upgrade if they catch the bug.

I am thinking:

1. Best (flattest/smoothest?) sound without trying to get too deep, likely standard Ported Box?
2. (Tentative) Prioritize lower extension. Maybe some type transmission line/horn (the terms here are confusing). Or a metronome, mini voigt tubes or voigt pipes (I think the mini-sawtooth ones look cool).
3. (Tentative) Just for fun I think I will at least try some variant of the Cornucopya Foam Core, or other flat-ish mount on the wall design. That might even translate into another project for my living room TV (yes I could buy a soundbar I guess).

Part One: Standard ported box​

Ql (Box losses) = 7
Vb (cu.ft) = 0.12 cu.ft / 3.4 l
Fb(Hz) = 71.9
F3(Hz) = 62.4
Port Dia = 15 mm
Port Len = 21 mm

I have attached the pictures from SpeakerBoxLite. They seem to match what I could squint sideways and see in the other programs (WinISD and Hornresp), but I don't really understand them. SpeakerBoxLite seems to automagically place and space the speaker and port, I don't know how to figure out speaker placement or spacing in the others.

If this looks OK, should the speaker go on the large side, or the narrow side? I thought the "Pico Neo" design had the speaker & port on the narrow side, but then I read something about having the speaker baffle (I take this to mean the side surrounding the speaker) to be at least the speaker diameter from the box edge to the speaker/cone edge, which gives something approaching the wide one.

And the calculated port seems tiny at 15mm, and the port velocity is off the chart. But when making that something like 25mm/1" it squiggles up the SPL graph. Although at 15mm, the length seems to essentially be the depth of the baffle at that size. Should I just drill a hole there, then see if it makes noise - thinking that I can always make a bigger hold and put a tube in there?



Thanks for any help,
Darrell

I'm trying to get into Camilladsp but being new to both this app and Linux I'm having a few problems installing it correctly. Rather than try to read all 192 pages, I thought I'd search within that thread to find all references to the word 'install'. When I do that though, I get 10 pages of search results, the oldest of which links to page 72 in the thread. The word 'install' occurs multiple times in earlier pages - why are they not showing on the search results?

If there's a way round this limitation on search results, can you point me to it? If not, I can imagine that I and many others will be asking questions that have long since been answered, just because there's no way to find that answer. Could get very annoying to those who know what they're doing...

would like to build unbalanced version of this DAC [Pass D1] have 2 PM63,8412's and 5At and I want to use pass I/V stage. If gerber files are available I would get pcb made.
best regards,
Steve

Trough time has some great engineers made amplifiers that stood out, amplifiers that raised eyebrows because of how better they were.
But are they still special today, do they still deliver something above the rest?

I do know some say it can be argued that every non defect solid state amplifier sounds completely the same., but let's ignore that and just follow the hype.

Is there some with still available schematic and pictures of PCB that is still clearly worthwhile to make?

Need a little advice Long spring on cd transport has become unattached on one end and cannot seem to find where to attatch

hi!

happy to be here. what a huge place hence sorry if this has been answered somewhere at some point.
so i'm revamping my gear a bit and came across a fairly simple question: do capacitors affect the frequency range's end?

let's say my cabinet's high frequency range starts dropping at 13khz and i would like to improve that. would replacing the capacitors of the crossover with better ones change that? or does it only depend on the tweeters? or maybe both?

thanks in advance for any insight 🙂

I have the 28 step version of Dave's autoformers. This doesn't have the flying leads that the 24 step does. There's a ground terminal and the various attenuation terminals but there's no "IN" terminal. What is signal supposed to hook up to? Thanks.

12 pieces USED but working

Foe sale a nice Nos pair of 12sl7 Tungsol black glass and a pair of the best 6sl7 tubes out there National Union black glass also Nos. Tubes are new in box, I buy this from Langrex UK a great tube seller store. The price for bouth pair would be 150 euro including tracked shipping EU. Payment Paypal.

Hello, please for your help.

I have 2 tranformers with 2X22/300VA.
I want to power the BA-3 amplifier .
The psu is the diystore Universal Power Supply.

How can i connect the two tranformers ?

Thank you in advance

I have a NAD C350 that I picked up for nothing. I am teaching myself how to trouble shoot and repair electronics and I think repairing this amp will be a good project. I have no experience but I am eager to learn.

When I connect speakers and an audio source I get no sound. The speakers work fine when connected to a different amp. The C 350 goes into protection mode when turned on (The power LED light stays red) and nothing makes it to the speakers. The inputs seem to respond normaly. When I select a different input I hear the relays clicking and the corresponding LED turns green. This leads me to think the power supplies are working properly and the problem is somewhere on the amplification side of the unit.

What things should I check first and how should i test them?

Hello everyone!

I'm an electronical enthusiast and beginer in this beauty world!

I have an URSS oscilloscope that it's broken and from a while I try to fix it.

The main problem it's in the high voltage power supply, another problem it's my lack of knowledge about CRT and how they work.

I found the data sheet for this CRT valve but I can't understand what it's the pin no. 2 on and what this is doing. First I try to repair the original power supply which is made with an iron powder transformer and self-oscilation circuit but this doesn't work properly and I couldn't make this supply to work properly.

Now i try to make another type of power supply that it's based on push-pull topology and another core ( ETD34 ) at 30kHz. unfortunately I didn't had time to experimented with this new supply.


What I want to understand it's what does every plate in this tube and how it works. I want to check all the supply voltages without the tube connected (with some load resistors) to be sure that everything it's fine.
I didn't saw this CRT at work, I received the osciloscope ( C1-118A URSS model) few months ago as a "gift"and broken, but as I knew the device worked in the past, now the tube seems to have some good signes, the filament it's glowing, and also I don't know why this appear and also if it's bad or not for the tube itself.
For sure the tube doesn't accelerate. Maybe with the new transformer the tube will work without any problem, anyway I want to learn from you and hear your opinions!
I'm looking forward for your answer and I really want to learn more about CRT and electronics.

Thank you in advanced!

I know that on:
pin 1 and 14 it's the heater lamp (also this it's checked and it seems to be ok )
pin 2 it's a mistery (this pin it's connected via an potentiometer between -12V and +100Vcc), maybe with this pot can I adjust some geometrical issues?
pin 3 it's the cathode
pin 4 it's the gride
pin 5 it's the 4th anode
pin 6,9,11 not used
pin 7,8 X (time base ) plates
pin 10 astigmatism
pin 12 focus
pin 13 2nd anode accelerating
D1,D2 Y plates

http://lampes-et-tubes.info/cr/11LO9I.pdf
11LO9I (11ЛО9И) Oscilloscope CRT


For more photos I leave below links:

At least he's learning from a reputable source, Tomlinson Holman. I would have thought the graphs, measurements, and technical info would bore him. but he's been at it for several hours.


.

Looking for a pair. Please PM. Thank you!
Discussion Thread

OK,


So I have built this 813 PP amp...i like it alot, but feel the need for some more mojo in the driver stage.

Current drivers are EL34 Svetlanas , triode connected, B+ of 350V , in a choke loaded cathode follower config, RC coupled to the 813s ( 813's are at B+ of 615V) . The EL34's are driven by the phase splitter , an RCA smoked glass 6SL7GT.

I was looking at a GU50 , until I saw this video Login to view embedded media
and noticed the inside of the anode is some silver colored (metal).

And another on my sort list was Mullard EL37's (in triode) but they cost too much.
I wonder what these 807 Haltron Tetrodes would sound like https://www.trademe.co.nz/a/marketp...pment/vintage/listing/3937708870?bof=yiUoDAEr


Opinions or suggestions anyone?

I made it through most of the hundreds of pages of threads on distributed mode loudspeakers (DMLs) around here, AudioCircle and Parts Express' forum, I decided I wanted to try building a couple of my own panel speakers. I did it yesterday and they sound great. Pictures to come, but I'll start with background first for those who are interested but would rather not have to wade through the gigantic existing threads.

To recap what I found in previous DIY threads:

1. Basics of the technology:
   1. From a Parts Express customer and DIYer: DML Flat Panel | Parts Express Project Gallery
   2. From Techtonic Audio Labs (owners of the intellectual property from the now defunct NXT): Professional Distributed Mode Loudspeakers |
2. Material stiffness and size matter, especially with respect to reproducible frequency range and especially in the bass where bigger and stiffer is better. Weight still needs to be kept down though for efficiency and max SPL to be acceptable.
3. The best panel materials DIYers have found so far are, in no particular order:
   1. 1/8" or 1/4" birch ply
   2. XPS or EPS insulation, around 1" thick, with the paper coating sanded off and new edge treatment for stiffening such as diluted wood glue or shellac.
   3. Heavy-duty foamboard or signboard, the preferred brand being Gatorboard: http://www.dickblick.com/products/gatorfoam-board
4. Commercially available high quality DMLs use materials not easily available to DIYers.
   1. For live pro audio, Tectonic uses carbon fiber sandwiched around nomex honeycomb: https://www.youtube.com/watch?v=aFFfQ1b5EQQ
   2. Podium Sound makes home hi-fi DML panels using what sounds like a one-off phenolic paper honeycomb: 6moons audio reviews: Podium Sound Model 1

I thought, there has to be a way to get the materials together for something like pro construction, although part of the fun with DML seems to be that you can make a speaker out of literally anything, so why not try and see what happens?

In the next post: the search for commercial composites and honeycombs.

New Price: Full Sugden Masterclass SPA-4 Class-A Amp Kit PCB and all parts

For Sale complete Sugden Masterclass SPA-4 Kit, including:
-Two SU9716 PCB, Sugden Masterclass SPA-4 amplifier PCB with all the parts (Sanken 2SC2922 and 2SA1216 output transistors)
-Additional SU9801 Speaker Protection PCB (includes the +/-18V supply needed for both input PCB).
-Additional SU9802 (L) & SU9803 (R) Balance Stage PCB, Single Ended and Balanced Inputs (with SE/BAL Converter).
-Special Mica insulators for the amp Sanken transistors MT-200 pack (39x24mm)...
-Includes all docs, schematics, detailled BOM, PCB silkscreen for assembly and test.

The amp uses a pair of Sanken 2SC2922 and 2SA1216 output transistors, a DC servo.
The Speaker protection and input PCB were done by me, using the original Sugden schematics. They are fully functionnal and tested.
The Two amp PCB were partially tested with current limited +/-35V supplies, and no heatsink. So final full bias test (900ma according to schematic) needs to be done on appropriate heatsinks...

So you have all the needed parts to build complete Sugden Masterclass SPA-4 Amplifier, just need to add the +/-35V supplies, connectors and an enclosure with heatsink...
I bought the two amp pcb from an other member years ago, private sale.
I made the missing pcb (input and protection) to complete the amp myself.
Schematics available on request...

Asking price is less than cost of parts (more than 550U$ + shipping). Just have to many projects, this one needs to go. My loss, your gain...

Asking price 400U$ (Or best offer) + shipping + Paypal 3.5%

Hi there,
I was given an AK4390 based DAC by a friend. Unfortunately the DAC came without opamps in output stage. Can someone help me to determine what type of opamp this circuit is suited for, BJT-input or FET-input?

So for my first post here on diyAudio, I asked about the SAA7220 being removed from my new to me 965BX; I know this player is not a super-duper, but if I could make it play happier in my system I think it would improve on the Pioneer 609 CDR box I currently use (!)

When it arrived, the ball bearing holder bit in the floating clamp had actually broken out, and was jamming the whole thing - so I've reglued that in place, and after discovering that it should actually have a ball-bearing in it, managed to find it on the carpet about a foot away from where I dismantled it - so that went back in as well.

I've managed to make the tray go in and out better (put the rubber belt in very hot water for a few minutes, and cleaned it well); mended the open/cls button by super-gluing three bits of small shrinkwrap to act as hinges, which work really well; one of the clamp springs had stretched, so I cut a bit off, and reformed the loop and started the process of fitting a figure 8 mains socket rather than sticking with a flying lead.

But I have one very important problem yet to solve, and some advice would be gratefully received. The damn thing will play all the tracks from the inside 3/4 I guess of any CD I throw at it, but then the last few tracks will drive it bananas, skipping like crazy. I've cleaned the lens a bit, I've tried putting extra pressure on the clamp, I've removed and refitted the mechanism, but none of that seems to make any difference.

I realise that there probably isn't an obvious answer, but some thoughts on what to try would be great - other than the "buy a new mech / player" reply !!

Hi all, i would love to hear a decware sound in my system, therefore im looking for a used decware zen diy clone or a used original to buy.
I live in the Netherlands.

Sincerely, Walter