I have a weird issue with my old Denon 970 amplifier, it makes a sizzling/buzzing sound after it's been off for a while and it has to charge the main PSU caps. After it's charged, the sizzling noise stops.
I've checked the caps around the protector circuit and the relay has had its contacts cleaned but the issue is still there.😕 It doesn't seem to come from the power switch either.
I've checked the caps around the protector circuit and the relay has had its contacts cleaned but the issue is still there.😕 It doesn't seem to come from the power switch either.
Are you talking about a sizzling noise in the speakers or a sizzling noise comping from in the amplifier?
It's coming from the inside of the amplifier itself, like a short 'zapping' sound, sometimes for 1-2 seconds after switching on. Couldn't find any burnt spots, no magic smoke to be found either.
Last edited:
A Sizzling noise is well known to me in another field Radio & TV in other words arcing of electricity so resolder capacitor contacts --look for dirt /dust in the power supply --check for blackened markings in unit --buzzing is a different story.
LOT=line output transformers in CRT TV,s were famous for this ,could end up replacing the transformer even dust on the tube or wired in EHT diode caused arcing .
If its buzzing then check the mains transformer for loose lamination's or security to the chassis ( bolted down ) .
LOT=line output transformers in CRT TV,s were famous for this ,could end up replacing the transformer even dust on the tube or wired in EHT diode caused arcing .
If its buzzing then check the mains transformer for loose lamination's or security to the chassis ( bolted down ) .
The tranformer is a potted toroid, seems dead silent. The noise occurs only when the amp has been switched on after a break of at least a few hours. It's so strange that it only does this when powering up and is completely silent after that. On the other hand, if something was arcing, it should've been audible in the speaker and cause a smell?
Maybe Craig is right but if the switch is okay a bad soldered joint or HR joint when subject to a high current as will happen at switch on into a low impedance will arc and heat up .
