Randall RH200 strange noise??????

[Jazz P Bass]

The schematic shows that the signal goes from IC4 to the tone stack.

IF you can get IC4 to stop the noise, it would be informing to know if any IC's further down the line are involved. (maybe you did this already)

If the problem is isolated to IC4, I would try the grounded cap test on it's input pin (6).

Seeing that the IC was replaced we must move on.

[sweatyk]

The schematic shows that the signal goes from IC4 to the tone stack.

IF you can get IC4 to stop the noise, it would be informing to know if any IC's further down the line are involved. (maybe you did this already)

If the problem is isolated to IC4, I would try the grounded cap test on it's input pin (6).




Seeing that the IC was replaced we must move on.

IC4 was not replaced it was swapped with IC2 so I may have created more of an issue if that's the case....

[sweatyk]

To tell you the truth I have become a little flustered with this amp. I have replaced nothing. Merely swapped two chips around and may have confused you guys a bit. I tried to be as explicit and detailed as possible. Now I know I'm not losing my mind when I grounded that cap last night on IC2 and the noise disappeared. Repeated the exact process today and had an opposite effect. That's a head scratcher to me. You guys have a lot more knowledge and experience with this stuff but this isn't my first rodeo and I rely on common sense which to me this makes no sense. At this point I'm ready to order a few new 072D's and go ahead and replace IC2 and IC4 and start from there. Plus any chip I replace is getting an IC socket installed because I have removed IC2 several times in this process and the traces are starting to lift so this should help reduce the damage to them unless someone here thinks that's a bad idea. I'm sure it will take a week to get them so in the mean time if there are any more suggestions my ears are open. I was hoping that the 2 audio links would provide some help. Hearing it for yourself is better than someone trying to describe it. Please let me know if the uploads are functioning.

[sweatyk]

Has anyone been able to play the videos/audio I posted of the noise this is making? I took a break from it for a week and ordered new 072D's to replace IC2 and IC4. I also repeated the .01 uf cap grounded and to pin 7 on both replaced chips. The noise only intensified. I'm up for suggestions at this point. An O-scope would probably make this a quicker process but I do not have access to one.

[Jazz P Bass]

At this point, I would try the cap on the input pins.
You need to find where it starts.

[pontiacpete]

Has anyone been able to play the videos/audio I posted of the noise this is making?

I was able to play your audio clip.