I have an amp I've been working on for weeks now, can't get rid of the noise. I probably just don't have the skills to make it work right, though my soldering, layout and cable management are top-notch.
All parts were purchased new during the last 30 days, including 4 modulus 86 boards, all parts to populate it, an Antek AN-5220 toroidal transformer, a DIYaudio power supply board including 8 15,000uF Nichicon caps rated 5,000 hours at 105C.
It's a complete amp, it works and sounds great except for the noise. I'm not sure if it's my signal source that is creating a ground loop but right now I'm blaming the amp since I have another one which causes me no trouble.
If you know what you're doing you may be able to solve the problem I have not. The whole thing will be shipped assembled to you for the asking price of $600 (continental united states).
All parts were purchased new during the last 30 days, including 4 modulus 86 boards, all parts to populate it, an Antek AN-5220 toroidal transformer, a DIYaudio power supply board including 8 15,000uF Nichicon caps rated 5,000 hours at 105C.
It's a complete amp, it works and sounds great except for the noise. I'm not sure if it's my signal source that is creating a ground loop but right now I'm blaming the amp since I have another one which causes me no trouble.
If you know what you're doing you may be able to solve the problem I have not. The whole thing will be shipped assembled to you for the asking price of $600 (continental united states).
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Yes, I've got a thread I started here to try and get some outside advice. Nothing I've tried has worked.
Someone just posted that thread above.
I had a similar amp , but with the parallel86 boards, of course from neurochrome.com
and I had 0(zero) complains, no noise ,no pop up noise , just great sound. I used a single ended to pseudo differential cable, just like you,
the difference was that I had only 2 channels, not 4.
Your amp looks great!
and I had 0(zero) complains, no noise ,no pop up noise , just great sound. I used a single ended to pseudo differential cable, just like you,
the difference was that I had only 2 channels, not 4.
Your amp looks great!
In the meantime, you might try this with your amp to track down the noise or ground loop:
Disconnect all but one amp unit from the PS and inputs. Connect the remaining amp board, power up, and see if the noise is still happening.
I had a strange noise problem in a multichannel set up. After much sleuthing it seemed that the noise was picked up by the interconnects when they were not bundled tightly (like all wires within the same jacket a la a snake cable). By using just one amp, and having only one cable connected, you could rule this out at least.
Also, make up a shorting RCA input plug. Just an input with signal and gnd shorted together, no cable, etc. Plug that in to the single active amp module's input and fire up the amp. Any noise? There shouldn't be. If there is the culprit is definitely inside the amp, possible in the PS e.g. noise from the diode bridge diodes or whatever, pos/gnd/neg not tightly twisted or woven into a triplet within the amp, or two ground locations (e.g. earth ground on chassis next to AC mains socket AND RCA jacks grounded.
Dont' give up, that should be an awesome amp and you spent lots of time on it already. The answer might be so close!
Disconnect all but one amp unit from the PS and inputs. Connect the remaining amp board, power up, and see if the noise is still happening.
I had a strange noise problem in a multichannel set up. After much sleuthing it seemed that the noise was picked up by the interconnects when they were not bundled tightly (like all wires within the same jacket a la a snake cable). By using just one amp, and having only one cable connected, you could rule this out at least.
Also, make up a shorting RCA input plug. Just an input with signal and gnd shorted together, no cable, etc. Plug that in to the single active amp module's input and fire up the amp. Any noise? There shouldn't be. If there is the culprit is definitely inside the amp, possible in the PS e.g. noise from the diode bridge diodes or whatever, pos/gnd/neg not tightly twisted or woven into a triplet within the amp, or two ground locations (e.g. earth ground on chassis next to AC mains socket AND RCA jacks grounded.
Dont' give up, that should be an awesome amp and you spent lots of time on it already. The answer might be so close!
+1 for the shorting plug suggestion.
You're more than welcome to contact me via email. I seem to recall that we did speak a while back. If I've missed an email from you, I apologize. My email volume is pretty high these days as I'm getting quotes together for the Modulus-186 and -286 manufacturing and the Modulus-286 kit.
The Modulus-86 should be dead quiet. My 4xMOD86 amp (built like yours, except for I use balanced inputs) certainly is.
I'm not impressed with the layout of the supply board that you're using. Whoever designed that did not make good use of the available copper in my opinion. I can't say for sure if that's the root cause of your issues, but if the more obvious suggestions fail to yield results, that's something I'd look at. My Power-86 or Power-686 would be a good fit and you can probably reuse the caps.
What kind on noise are we talking about? Hiss? Hum? Something in between?
Anyway. Should you decide to sell, someone will get a screaming deal for sure. It looks like a nice build. It's probably $800ish just in components, chassis included.
Tom
You're more than welcome to contact me via email. I seem to recall that we did speak a while back. If I've missed an email from you, I apologize. My email volume is pretty high these days as I'm getting quotes together for the Modulus-186 and -286 manufacturing and the Modulus-286 kit.
The Modulus-86 should be dead quiet. My 4xMOD86 amp (built like yours, except for I use balanced inputs) certainly is.
I'm not impressed with the layout of the supply board that you're using. Whoever designed that did not make good use of the available copper in my opinion. I can't say for sure if that's the root cause of your issues, but if the more obvious suggestions fail to yield results, that's something I'd look at. My Power-86 or Power-686 would be a good fit and you can probably reuse the caps.
What kind on noise are we talking about? Hiss? Hum? Something in between?
Anyway. Should you decide to sell, someone will get a screaming deal for sure. It looks like a nice build. It's probably $800ish just in components, chassis included.
Tom
ModuShop Dissipante 2U.
That's not necessary with the Modulus-86.
Anyway. I just noticed that the original post is from 2017. This probably isn't relevant anymore.
If OP has decided to give it another go, I'm more than happy to help.
Tom
I don't know the layout of the Modulus-86 PCB but with four modules sharing one PSU, I would use the PSU gnd as speaker return instead of using the gnd on the PCB. This fixes many gnd loop in multi-channel setup using single PSU.
Line inputs are too close to AC lines... Same for the supply are too close to transformer, unless picture angle is not good. I would have put two modules close side by side with the size of this heatsink (would be a no brainer) to minimize cable length and keep them away from transformer.
This can all be fixed very quickly.
Do
Line inputs are too close to AC lines... Same for the supply are too close to transformer, unless picture angle is not good. I would have put two modules close side by side with the size of this heatsink (would be a no brainer) to minimize cable length and keep them away from transformer.
This can all be fixed very quickly.
Do
That's the official diyAudio board I believe. I'm not sure if it's the current board or a previous incarnation as I believe there have been a couple.
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