The collector sits at 30V. Does this make sense to you? Amp running now as it should, no oscillation, no noise at the speaker outputs.
Pleased to hear it was an easy fix 
The top end of R604 should be at around 31 to 32 volts.
Q602 C will be at wherever it takes to achieve that depending on the loading of the 30 volt rail. The actual fitted value of R604 is crucial to what the voltage is on Q602 but the value is not at all critical to the regulator working correctly. See what's fitted for curiosity... it might be a wire link
The top end of R604 should be at around 31 to 32 volts.
Q602 C will be at wherever it takes to achieve that depending on the loading of the 30 volt rail. The actual fitted value of R604 is crucial to what the voltage is on Q602 but the value is not at all critical to the regulator working correctly. See what's fitted for curiosity... it might be a wire link
Well, what do you know. Seems the regulator does need more than 100 nF to remain stable then. Interesting.
Effective PSRR in this amp may still leave some room for improvement though.
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I will hijack this thread - I just purrchased a 5 years old Denon AVR-2313 and it says prrr. The cadget runs quite hot because of video circuitry being active all the time.
I mostly listen to active speakers connected to line out R/L. When I turn on Denon (from standby), prr gets much louder and is easily heard in a silent room. When input is changed, prr goes away for a moment. After it was disconnected from mains, it was almost silent for a few hours. So, my guess is that some capasitors are drying out.
I can't do service and I haven't even opened the case yet. What do you think are chances to get this prrr solved if I carry it to AV repair shop?
I mostly listen to active speakers connected to line out R/L. When I turn on Denon (from standby), prr gets much louder and is easily heard in a silent room. When input is changed, prr goes away for a moment. After it was disconnected from mains, it was almost silent for a few hours. So, my guess is that some capasitors are drying out.
I can't do service and I haven't even opened the case yet. What do you think are chances to get this prrr solved if I carry it to AV repair shop?
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