Marshall Artist 3203: Schematic and Mods?

[tms13pin]

Just picked up one of these. SS preamp and tube (2xEL34) output stage.
Interesting amp. Wondering if anyone has a set of schematics and if
anyone's played around with some mods (more power amp gain, more
drive gain, tone control tweaks, etc.).

Thanks.

--Tom

[SatelliteAmps]

Link to schematic:

http://www.schematicheaven.com/marshallamps/artist_30w_3203.pdf

There are a few mods that can be done to this amp, but honestly, it's a good amp as it is and most of the mods don't really improve it.

[tms13pin]

Thanks for the link! I still need to spend more time with it but
my first impression of the gain channel is that I had to crank the
gain up pretty far to really get it to saturate nicely (this was using
my Brain Moore C90 w/ a Duncan JB and Dimarzio PAF Joe). Maybe
it cranks more with a chunky set-neck axe like a LP, etc. I'll have to
try more guitars.

I'd heard good things about these and picked this one up on ebay a
week or so ago. I rarely get to crank anything up at home (5 yung'uns)
so the lower power appealed to me. I've also got no idea how old the
tubes are (or what they are, I haven't pulled off the back panel yet).

--Tom

[SatelliteAmps]

Those usually sound pretty good at lower volumes. I've had a couple, and they were all great amps. You might just need a new set of tubes and a bias.

[tms13pin]

Those usually sound pretty good at lower volumes. I've had a couple, and they were all great amps. You might just need a new set of tubes and a bias.

From the schematic it looks like the bias is fixed. That's pretty easily
remedied though... any idea what a good bias range for these is? Not
sure if you've actually tinkered inside one or not.

thanks much.

--Tom

[SatelliteAmps]

I've tinkered inside them, and I've replace 3 output tansformers on them from guys who followed some mods they found on the internet. Bias range depends on B+, but there are plenty of charts to help with that.

You can install a bias pot inline with the bias resistor, and that will give you enough adjustment to play with.

[FrankieSixxxgun]

www.drtube.com should have a bunch of info too.

[Zero]

I modified mine with something I read in the HC review of the 4203 Artist combo, I believe it was the C13 resistor. It was a long time ago but anyway, it helped the Normal channel a lot. Didn't change the Boost channel. The Normal channel stock was all distorty. Couldn't get a decent clean sound. It was much better after C13 & I remember when I brought it to rehearsal after that, bandmates who never notice shit about my sound asked what was different when I was playing clean stuff.

[SatelliteAmps]

C13 is a capacitor. The mod is to cut it off the board, or at least one leg of it to lift it from the circuit.