Randall RG100G3 preamp overdrive problem

[Dinky88]

hello.

Ive got a randall RG100G3 thats been behaving very strange on the overdrive channel.

Been trying for more than 2 years to sort it out, even had it at a tech, he mamaged to fix the power amp that was getting very hot and the annoying hum that the amp made.

He couldnt help with the overdrive problem because hes not a guitar amp tech or guitar player. Not many guitar amp techs here were I stay in South Africa.

I hope someone here can help me.

My problem is that both OD 1 and 2 gets very mushy when i turn the level up on that channel, cant turn it up more than 2/10.
I also get a crackling sound when hitting the high strings, like i hear the note followed by a crackle, its high pitched sounding.
The pre amp, not the amp will also start to cut out after a while, i can still use the clean channel after the overdrive stopped working.

Ive been testing this amp with lots of different cables, guitars, changed the valve in the power amp, it uses a valve in the power amp to give it a tube amp response and feel.
After more than 2 years ive singled the problem out to just the overdrive section of the preamp.

I would greatly appreciate ANY help or advice.

Thanks

[shooter]

I'm guessing if you have 2 yrs into an amp n it ain't fixed...........
I'll assume you know electronics, safety, got a schematic etc.  the only one I have at the moment is this one

link

the only big thing that sticks out to me is the diodes on the reds output fet, take 'em out for testing n see.
post a schematic n it'll be easier

{EDIT: fixed broken link --PRR}

[smackoj]

I would suggest going to ssguitar.com and check their files. They have several posts by guys working on that Randall Amp.