Distortion after ~12 hrs

[casscors]

I have had my P10 rev4 since release basically, and as my master keyboard I tend to keep it on almost 24/7 so I can always jam.

The last couple weeks, I've noticed I'm getting distortion and low output level after the synth has been left on for 12 hrs. Power cycling it will alleviate the issue, but it will randomly start again if the synth is left on. I now have to power cycle the synth at least once per day. Also, I seem to have more serious pitch drifts and every time I tune I'm now up to 50º C despite the AC-equipped studio being 73F.

I saw another thread mentioned swapping TS cable for TRS, and I just tried that but the distortion remains. I believe something is causing the filters to bug out based on what I'm hearing. I've been keeping the synth in Stack mode often with my recent work, and I noticed some other odd behavior that may be related to this. It sometimes seems as if the panel and the synth itself can lose sync.

Prophet-10 --> Passive DI --> Console --> Converters. Checked for ground loops and tried lifting

[jdt9517]

I have had my P10 rev4 since release basically, and as my master keyboard I tend to keep it on almost 24/7 so I can always jam.

The last couple weeks, I've noticed I'm getting distortion and low output level after the synth has been left on for 12 hrs. Power cycling it will alleviate the issue, but it will randomly start again if the synth is left on. I now have to power cycle the synth at least once per day. Also, I seem to have more serious pitch drifts and every time I tune I'm now up to 50º C despite the AC-equipped studio being 73F.

I saw another thread mentioned swapping TS cable for TRS, and I just tried that but the distortion remains. I believe something is causing the filters to bug out based on what I'm hearing. I've been keeping the synth in Stack mode often with my recent work, and I noticed some other odd behavior that may be related to this. It sometimes seems as if the panel and the synth itself can lose sync.

Prophet-10 --> Passive DI --> Console --> Converters. Checked for ground loops and tried lifting

Have you tried programming it with the distortion?  Did you get good  sound? Assuming you dont like the sound, Another thougt is to take to sequential and let them work on it. Since it replicates the problem, the fix should be easy.

[casscors]

I started playing today and had the distortion again. Part of me worries it's related to grounding or something along those lines, so I went ahead and swapped some things around so the entire studio has AC star-grounding via my UPS.

Will find out if this fixes it.

[casscors]

Well after quite a bit of self-doubt and testing I am sad to say that the prophet still has this level drop issue. It is remedied with a simple power cycle, but it looks like I'll have to send it in sometime. I have found that the distortion component doesn't always seem to be there.

Between experimenting with grounding and cables over the last month, I've got 3dB lower noise floor when monitoring each of my synths which is cool I suppose. Prophet ain't even 2 yrs old though, and I got stuff from 1989 still running peachy....

[SynthHead]

Sounds like an OP-Amp issue perhaps? I'd think it would normally 'distort' all times if so, but I guess it could be a kind of fault that only shows after its hot enough... I saw this on old Alpha Junos and soldered in a new op-amp, noise gone... but on a new prophet rev 4 the parts should be way more robust and also.. harder.. to solder yourself if so!