Electronic amp guys help pls. basic mod help

[mrjones200x]

Hi there,

 

Been mucking about with my little marshall ms2 and i fancy modding it some more but i dont know jack about how amps work and so on.

 

I'll post a link to the schematic of the amp if anyone wants to help.

 

http://www.diyaudio.com/forums/attachme ... ostack.gif

 

I really dont even know what i wanna do just mess about really and see whats achievable. I quite like the basic tone of the amp and its fun and cheap so why not.

 

Ive already put in a speaker jack to power a bigger cab if i wanted but now im thinking is it possible to get more gain? Do i bypass the tone stack for this? any ideas for fun things to try?

 

Probably very simple for you guys who know your stuff. Be nice to learn something about amps

 

Thanks

[m-theory]

You schematic linky doesn't seem to work.

 

This is a tiny little solid state amp, isn't it? If so, I can't imagine it being worth modding, frankly, but if what you want it more gain, yes you could just bypass the tone stack. Or, put a booster or overdrive pedal in front of it.

[mrjones200x]

Heres a the schematic pi. How would i bypass the tone stack? Thanks

 

 

[m-theory]

Run #2 terminal of the volume know straight to SW1b, and you'll be rid of the tone stack. What that will do to the rest of the circuit remains to be seen, of course. It was obviously designed as you see it today, so it's possible that it won't behave itself when it's altered, and you may introduce uncontrollable oscillations by doing this.

 

Again, imo it's really not worth fiddling with. I'd put a boost in front of the amp and call it modded, but it's your amp. Bust it open and start tinkering if you feel the urge!

[jefrs]

I've got one of those things. Sometimes I use it as a circuit tester, most other times it's a piano ornament.

 

You could monkey with the nfb 1.2M resistor on the OD gain stage of the C3198 or mess with the components on pin3 (gain) of the IC. I'd leave the tone knob alone.

 

As it already has a headphone/speaker socket... ?

[Dave]

M-theory, It looks to me like the cap marked 22n would still be in the circuit through the tone control if he ran a jumper from the stator of SW1B to the top of the volume control. Is 22n part of the tone RC network or is it a DC isolation cap for the circuit? Maybe the 1n cap is part of the tone control instead instead of being a signal coupling cap that blocks DC from the OD circuit. There would still be some activity on the tone control when the stator was adjusted toward the cap 22n even with a wire installed from the SW1B to the volume control, IMHO. It looks like there would be some signal shunt to ground as the tone control was rotated that direction. There could be some HF loss through the cap 22n. Maybe it would be negligible ...

 

Just an observation.