Hi everyone, I will say that i have quite a new hobby of fixing audio gears. i might solve some basic problems and would like to have your help with this one. This receiver i've got, i already dioxide all its potentiometers, so i would say the issue is not related to dirty contacts. the issue is, that in low volume, the sound is fine. but when i raise the volume for average music volume, its start making "boom" like small explosions (especially when it's should playing bass beats) findings: 1. it's happening in both L/R channels 2 it's happening in all audio inputs (tape, aux, phono and also tuner) 3. it's happening also in the headphones jack. 4. it's not abut the speakers/cables i use. all the peripheral equipment is working Properly. i guess it's related to the preamp circuit? what should i do? Thanks a lot!