Do we do project times here? pictures and everything?

[diagrammatiks]

I'm reworking an amp for a client.

An epiphone valve special.

It's a pretty interesting design...umm, parallel triode into a voltage amp/dc cf into 2 to72s into a digital fx off board back into the power amp...

you can't ever turn of the dfx.

Still, the board traces look alright, and at least it's labeled as a hybrid amp, unlike some companies who claim their amps are all valve.

She's definitely not the belle of the ball.



Sounds so bad. so so so bad.

Smd board



thankfully I don't have to touch this thing at all.

and of course, the awesome obvious board errors.



no actually we can't screw down the pcb in 5 places through the ground plane.

[redelephant]

Hehe, this amp costs what? The hours you spend on modding it will cost...? Anyway, I guess if you get it sounding good it will be well spent time and money. Are you going to bypass the dfx? Do you know why it sounds bad?

[defaced]

I have one of these. The digital effects stopped working, so they found a home somewhere outside of the amp. I don't recall there being much if any tone change after removing the SS parts from the signal chain. The amp was a great test bed to learn about tubes, but it now sits quietly on the bottom shelf next to my bench with the chassis just sitting in place. I haven't figured out if I want to butcher it or just tweak the preamp a little.

[diagrammatiks]

spent about 3 hours pulling the board, tracing jumpers...

you can't actually test anything without assembling everything since the leads are only so long and the tubes will only go in one place etc etc.

so i threw that pcb into the sun.



that's better.

I think the reason the stock amp sounds so bad is because the dfx are smack dab in the middle of the signal chain.

the 2 preamp tubes are basically acting as a preamp for the solid state stages.

[tubeswell]

Looks positively hideous to work on

[diagrammatiks]

jcm800 pre into a 6v6 single ended + an additional gain stage off to a very happy camper.

[defaced]

I think the reason the stock amp sounds so bad is because the dfx are smack dab in the middle of the signal chain.

the 2 preamp tubes are basically acting as a preamp for the solid state stages.

Nope, the amp just sounds bad.

[Steve Conner]

I think it's unfair to dis the original build quality of the amp. It was much better than the sloppy mess you've made of it now with components and wires sticking in all directions.