Out of curiosity have you considered checking that you are getting stable clean voltage from the wall ?

If you haven’t already changed the PSU I would also do that but if it’s also occurring with a known good PSU then check wall voltages.

You might have a dirty power feed that the PSU can’t compensate for.

What power supply are you using with the system?

What you're describing sounds like my recent experience with finding a couple of cards that require -5v for proper sound operation. I was checking out an Opti 931 card and thought it was broken - stereo sound wasn't working, music super quiet, thought the amp was the problem so pulled all that off and bypassed it. The next morning realised I hadn't checked for -5v on that test system. Fitted the -5v power thinger and the card works just fine.
You can check for yourself if -5v is needed by the card by looking at the 5th ISA pin on the back of the card going from the edge at the back of the case:
pin B1: Ground
pin B2: reset
pin B3: 5v
pin B4: IRQ2
pin B5: -5v
pin B6: DRQ2
pin B7: -12v

If there's a pad on the -5v spot and it has a relatively thick trace going somewhere then it might need -5v to give proper sound output.

Maybe -12v is also bad, if you're using the same PSU each time? You might also have problems with serial mice if your -12v line has a problem.

1. Exactly what PSU (brand and model) are you using?

2. Are you sure it isn't the speakers? Are you sure the speakers aren't back feeding power into the cards from a faulty circuit? I've never heard of it happening but in theory it could be possible.

Thermalwrong wrote on 2023-04-08, 02:21:

What power supply are you using with the system? […]
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What power supply are you using with the system?

What you're describing sounds like my recent experience with finding a couple of cards that require -5v for proper sound operation. I was checking out an Opti 931 card and thought it was broken - stereo sound wasn't working, music super quiet, thought the amp was the problem so pulled all that off and bypassed it. The next morning realised I hadn't checked for -5v on that test system. Fitted the -5v power thinger and the card works just fine.
You can check for yourself if -5v is needed by the card by looking at the 5th ISA pin on the back of the card going from the edge at the back of the case:
pin B1: Ground
pin B2: reset
pin B3: 5v
pin B4: IRQ2
pin B5: -5v
pin B6: DRQ2
pin B7: -12v

If there's a pad on the -5v spot and it has a relatively thick trace going somewhere then it might need -5v to give proper sound output.

Maybe -12v is also bad, if you're using the same PSU each time? You might also have problems with serial mice if your -12v line has a problem.

That's a good thought, and some of these issues can be caused by a lack of -5v, but I don't think any of the cards he listed are known to require -5v (not sure about the Terratec?). I'm not saying that definitely isn't the issue though... it's worth checking just to be sure.

My question for the OP is: What parts\devices\speakers\etc. have been connected to or involved with all of the cards? It's a little hard to tell for sure based on your description.

For some reason this reminds me vaguely of the weird missing OSC trace issue I ran into several years ago... though I really doubt that's the case here since different motherboards have been used.

As cyclone3d said, I would also be suspicious of your speakers or even the speaker power supply. Being that they are Roland speakers, does your power adapter have the correct polarity? I don't know about the MA12, but virtually all Roland gear from back in the day used center negative polarity, which is the opposite of most devices. Speakers themselves are AC, so I don't know what exactly would happen if you inverted the polarity on a DC supply that was powering speakers. Maybe they work but they cause problems like this. EDIT: I just Googled it and the MA-12 have a standard AC power cord so they apparently have everything built right in. There could still be something wrong here, but it isn't the issue I mentioned above since these have no AC\DC brick.

EDIT: Also, check whether you are using line or speaker out, and if any of your cards have jumpers to select between line and speaker. Speaker out will be amplified and is intended for basic speakers that don't have an internal amplifier. Line out is intended for any speaker with it's own amplifier. If something you're using is screwing things up, possibly switching from one output to the other may reveal something.

Maybe the MA12s are dying? I had a situation where I thought I killed a card but it turned out my corsair speaker combo was giving up the ghost , which was a common issue with that specific model.

Thank you all for the input. Bear with me. I haven't had a chance to get in front of my test bench since I posted this. I report back with more details shortly. Just wanted to point out that I am using Older (but virtually new) Enermax and Sparkle PSUs. I have been using the same setup for years using the same power on an APC battery backup through an old Memorex power station. I've never had power issues. Every single peripheral has been changed at this point EXCEPT the keyboard running through an old passive KVM. I'll have more information shortly. Thanks again.

baracoota wrote on 2023-04-11, 16:17:

Every single peripheral has been changed at this point EXCEPT the keyboard running through an old passive KVM.

That might be worth checking.

Someone recently had two motherboards fried due to a KVM: Just burned two Leopard Rev C boards .. Help?

OK It's been a while. I just haven't has the time to dig into this. I found that most of my sound cards are fine with the exception of the (2) Ensoniq Soundscape Opus cards. I tested them all in a different room with all new hardware and all seems to be fine except the Opus cards will not allow the computer to POST. It hangs when they are installed. I did manage to boot with one of them one single time and that was it. I'll take it.

What I found on the original testbed setup was that I am missing the -12V on the motherboard. That is why the sound wasn't audible. The -12V is present on the PSU when nothing is connected, but is gone when connected to the AT (P8/P9) header. I removed my AT/ATX adapter and plugged directly into the ATX header (my P166 mobo has both) and the -12V is present and sound plays on both headphones and speakers! I used several motherboards during this crisis, so I'll need to look at those as well. For now, I have the KVM disconnected.

That's as far as I got, but at least I know why, not how. I'll keep plugging away. Thank you to everyone who chimed in and continuing to hang with me while I work this out.

Any ideas as to what might have taken the -12V rail down on the AT section of the board? All input is welcome. Appreciate any and all ideas.

baracoota wrote on 2023-06-11, 04:20:

OK It's been a while. I just haven't has the time to dig into this. I found that most of my sound cards are fine with the except […]
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OK It's been a while. I just haven't has the time to dig into this. I found that most of my sound cards are fine with the exception of the (2) Ensoniq Soundscape Opus cards. I tested them all in a different room with all new hardware and all seems to be fine except the Opus cards will not allow the computer to POST. It hangs when they are installed. I did manage to boot with one of them one single time and that was it. I'll take it.

What I found on the original testbed setup was that I am missing the -12V on the motherboard. That is why the sound wasn't audible. The -12V is present on the PSU when nothing is connected, but is gone when connected to the AT (P8/P9) header. I removed my AT/ATX adapter and plugged directly into the ATX header (my P166 mobo has both) and the -12V is present and sound plays on both headphones and speakers! I used several motherboards during this crisis, so I'll need to look at those as well. For now, I have the KVM disconnected.

That's as far as I got, but at least I know why, not how. I'll keep plugging away. Thank you to everyone who chimed in and continuing to hang with me while I work this out.

Any ideas as to what might have taken the -12V rail down on the AT section of the board? All input is welcome. Appreciate any and all ideas.

Since -12V are present when you connect to the ATX header directly, measure what happens right after the ATX-AT adapter to rule out a faulty adapter. It's not certain that it's the board's fault at this point.

OMG! I had the same thought while lying in bed last night and sure enough....the -12V pin on my adapter was recessed in the connector and not making contact!!! All of this over a pushed in pin on my AT/ATX adapter. Well, it really is the best case scenario as this means that there is no reason to think that anything should have truly been damaged. I need to retest the Opus cards in a different setup. I believe I should be able to get them working. Well sometimes its the little things that can trip you up!! I am so happy to know the root cause of this issue. I've been scared to use any of the affected hardware for fear of continuing to damage more parts. I think I can put this behind me and move forward again. Thank you everyone!!! Got some really great advice here.

That's great that you've got everything working now 😀

I've had the same issue with the low-cost AT > ATX adapters. Some of mine have hot glue holding the pins in place which helps.