Hi Mark,
Yes maybe I didn't recognize it well buzz from hum, but definitely the speakers are not reproducing it, maybe it's low pitched HUM. When I'm connecting headphones, and I start to insert the plug, first this buzzing is heard on the left channel, and when I push the plug till end the buzzing on the left is stopped and it's transfered on the right.
Untill now I did some rechecking and some smaller mods.
First I changed the power with the shielded one, connected the shield to the ground on the wall side.
After, I removed the fan that was inside on the heat sink. Fan was starting to work when the temperature gets hi and the noise was irritating, so I'll use one or two external for lowering the heat, and I'll try to find maybe other way of reducing the temperature.
No result.
After this I removed the big toroidal transformer to see if everything is OK with him. No visual problems. Put some anti-vibrating material like blue tack under it.
Next removed the board where 4 big caps ( 4 jamicon 15000 uf), two smaller transformers, ac input, 4 big elnas, and everything looks ok, nicely soldered no visual problems.
After I tried to put some Teflon tape around some of cables that are inside ( because the number and the way that these cables are put in chassis is more than chaotic). Also near torodial transformer, I put some aluminum tape, I tried to crate some kind of barrier towards nearby cables that are passing near.
But, the buzzing still was there.
After this, I disconnected the cable that supplies the headphones part and four led lights on the front of the receiver. This cable goes from the back of the chassis were is preamp, dac etc. towards the front of the receiver.
I must say that, after turning off headphone input, the sound is slightly improved, more detailed.
I'll try to recheck the amp board near the heat sink, and pramp/dac board and see if there could be some problem.
Thanks all, and write all ideas you have:scratch2: