Please help me out guys!
I took my Rotel RB990BX power amp to Nilam to sort out a heating issue on the amp. The bias on the thing was way off and it was starting to go into protection mode. Unfortunately, this amp was previously repaired by an amateur after it suffered some damage from the previous owner. The seller (on this forum) never mentioned that.
Long story short Nilam replaced a whole bunch of transistors and fixed some paths which were completely burnt off. Extensive damage which has now been corrected to factory spec.
But now the amp has a buzzing/humming sound on my speakers. This can be heard very clearly with ONLY the speaker wire connected to the amp, nothing else. Nilam has had another look and even he cannot pinpoint it. The sine-wave on the amp is pretty perfect and the components all read 100% in spec, yet the buzzing sound is there.
Tonight I noticed that when I touched the bottom screws of the amp I could actually changed the sound/pitch of the buzzing sound. Is this some sort of a grounding issue? Is there anyone on here that can help me save this amp? Or do I sell it for spares?
I took my Rotel RB990BX power amp to Nilam to sort out a heating issue on the amp. The bias on the thing was way off and it was starting to go into protection mode. Unfortunately, this amp was previously repaired by an amateur after it suffered some damage from the previous owner. The seller (on this forum) never mentioned that.
Long story short Nilam replaced a whole bunch of transistors and fixed some paths which were completely burnt off. Extensive damage which has now been corrected to factory spec.
But now the amp has a buzzing/humming sound on my speakers. This can be heard very clearly with ONLY the speaker wire connected to the amp, nothing else. Nilam has had another look and even he cannot pinpoint it. The sine-wave on the amp is pretty perfect and the components all read 100% in spec, yet the buzzing sound is there.
Tonight I noticed that when I touched the bottom screws of the amp I could actually changed the sound/pitch of the buzzing sound. Is this some sort of a grounding issue? Is there anyone on here that can help me save this amp? Or do I sell it for spares?
