jcm 800 Hiss problem Any tech guys in here?

[Jr_vw2]

So My JCM800 is really pHISSing me off (lol) as you can see in the video its crazy loud.

what ive tried so far...
replaced all input circuit resistors with new low noise metal film resistors of the same value
moved the grid stopper resistor to the tube socket and added a ground shielded wire as well
replaced both input jacks with new cliff jacks

also retubed and recapped ans set bias

not cable or pedal related.

any ideas?

https://youtu.be/UI3mKHCGtnQ

 

[DonP]

Re: jcm 800 Hiss problem Any tech guys in here?

I think you've go advice on a few other forums, but to me it sounds like you aren't getting a good ground on that high input. I would turn off the amp, insert a jack, and check to see if the ground from the outside of the jack is making it to the inside of the amp with a DMM. Or, turn it on and jumper a wire from the outside of the jack to the chassis face plate and see if the hum goes away.

If that fails, replace resistors as the other people are telling you. But I REALLY doubt any of those resistors are blown, they aren't hit with any power.