I have an intermittent crackling sound from the right channel of my Adcom GFP750 preamp.
Characteristic of the problem:
- Crackling is intermittent, sometime quiet, sometime accompanied with a pop
- Only happens with preamp in "active" mode. In "passive" mode, the gain circuitry is bypassed via relay and only go through the volume pot.
- Crackling noise still happens even if the volume and balance pot is not turning.
I have built DIY preamp, amp, and DAC but I have no electronics troubleshooting experience and really have no clue where to start.
Thinking about giving the balance pot a contact cleaner spray, but the random crackling noise still happens even when the balance pot is not turned.
Anyone have any suggestions where to start looking? Service manual and schematics is attached.
Thank you
Characteristic of the problem:
- Crackling is intermittent, sometime quiet, sometime accompanied with a pop
- Only happens with preamp in "active" mode. In "passive" mode, the gain circuitry is bypassed via relay and only go through the volume pot.
- Crackling noise still happens even if the volume and balance pot is not turning.
I have built DIY preamp, amp, and DAC but I have no electronics troubleshooting experience and really have no clue where to start.
Thinking about giving the balance pot a contact cleaner spray, but the random crackling noise still happens even when the balance pot is not turned.
Anyone have any suggestions where to start looking? Service manual and schematics is attached.
Thank you