Thanks for your reply Enzo. It's not a "complaint". As you can hear on the linked recording the noise makes the amp unusable. I'm trying to repair it. It IS the amp. I've tried it in different places before posting.
Here everybody is suspect unless proven innocent, so pease run the tests suggested above and describe what happens, control by control.
*You* have the amp, not us, so please do the tests we ask you, even if you find them useless.
And we ask *only* what we would do ourselves if we had the amp on a service bench.
Suppose the amp does power up and you say: "it´s not the fuse, I put a new one there before leaving home"
Guess what we´ll do?
Yup, you are right, we will
check the fuse anyway .And so on.
The controls do affect the noise as you can hear on the linked recording. Gain, Volume, Bass, Middle, and Treble, and each position of the amp simulation knob. This happens on BOTH channels with the FX return knob down to zero.
How would we know that?
It´s not a video so we have no clue whether you are touching any knob or not, nor you say "now I´m sweeping treble from 0 to 10" or"now I´m turning around" or "I´m putting the guitar horizontal" or whatever.
FWIW buzz drops *a lot* from 0:12 to about 0:22, yet guitar volume stays about the same, so you did NOT touch the volume control, so *what* did you do at that moment?
There´s also a noise burst at around 0:31 , plus other unexplained changes, but again, why should we solve a riddle?
SO, my guess is the noise is produced somewhere else than the FX circuit OR if it is produced by the effect circuit it reaches elsewhere somehow.
You may be right and maybe it's digital hash but, just out of curiosity, COULD it be a PSU noise? I'm not sure but I think this amp works with a bipolar PSU and I'm not very acquainted with these. Could it be a source of noise if some component is dead?
Hum, maybe; but this
kind of noise, very unlikely.
Anyway I'll check the DSP card as you suggest
The DSP crd and all other tests suggested in the same answer.
Also, I can't find a damn schem of this amp. Any one?
I don´t have it, but in similar amps I have seen that the main circuit is exactly the same, only instead of the spring reverb circuit you have a nice 6 or 8 pin flat cable connector labelled "To - From DSP card" or FX board , so main circuit can be btroubleshooted the normal way, and DSP card either works properly or not.
Absolute worst case, I guess you can unplug it and keep the effects less amp working.