I'm troubleshooting my Aquaboy Deluxe 2013 build, not yet ready to post a tech help post yet. Short story, I have high pitched noise, thought it was clock noise, but after removing all the chips its still there.
The weird thing is that it still passes dry signal, although a bit reduced, with all the chips not installed. Is that possible? Just wondering if that is what i should be troubleshooting now. There is a transistor buffer before the LF353 buffers, could it push signal through the feedback resistors in the op amps stages without the op amps there?
Edit: It works fine with all the chips in, just has the high pitched noise (just not sure of the source yet)
Could be an issue with your power section. I'd start there if only to rule it out.
Yep, power supply issue. I jumpered R58 initially, then just thought it had to be clock noise and got off track with thing passing signal without chips. I had some 1/2 watt 46 ohm resistors i stuck in in parallel, and it's all good now. thanks for getting me back on track.
Nice, I'm glad that sorted it. Yeah, any time I hear a 'whine,' I check the power section first. Also, be sure to keep your I/O wires clear of clocks to avoid interference.