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  • Modding el cheapo solid state amps with pleasant results (Ritmuller M-15)

Let me start by saying I'm not really sure why I'm posting this thread because at this stage I have so little information to pass on, have zero photos etc for guys who need pictures ? , and have no idea if there is much of a target market out there in our consumer society.
But maybe somebody can benefit if they have one of these amps, or similar, lying around.

My workbench amp is an el cheapo Ritmuller M-15 solid state bought for R200.
It's very dark and muddy. For a while I was convinced it was a bass amp.
Quite pleasant, at times, playing a strat through it but impossible to use with my other guitars with hot humbuckers etc.

I don't know if the characteristics are just a fault on my one, or if they are all like that.

So anyhoo I'm a tinkerer and I've been thinking about the circuitry a lot, and opened it many times to take another look and procrastinate about fiddling with it.

So phase one was I added a treble bleed on the volume pot. I had 1000pf as a starting point in the back of my mind, and scratched around the garage for old parts and salvaged a bunch of ceramic 220pf caps. So I added one at a time, checking the tone each time, and stopped at four in parallel making it 880pf.

Well it transformed the amp into a honky little tube-sounding amp.
Quite a bit of fun to play on with my strats and I'm still experimenting with twiddling the tone stack because the mid range pot setting influences the treble and bass setting a lot. I only did this job yesterday so still early days seeing what I can play on it. Still way to muddy for my pointy guitars though so still strictly a strat amp.

For phase two I'm going to add a really big cap, like 4000pf or so, with a switch so I can flip between the two treble bleeds and see how they differ for experimental purposes.

Phase three I'd like to delve deeper with tone shaping experiments elsewhere in the circuitry and try do a "proper job" of cleaning the voicing but I reckon I must source another one of these cheap amps to do that on and leave this one as-is as a reference point because it's going to get messy.

So I suppose the point of this post is to say if you have a rubbish solid state amp lying around it's not a total lost cause and it can sometimes be worthwhile to fire up the soldering iron and old braincells and see what positive changes you can make for the cost of electronic groceries ranging from free to a few Rand. If tinkering interests you
    That sounds cool- so the tone stack is essentially the same Fender TMB configuration?

    I know there are lots of threads on TDPRI and FX websites around on improving tone of cheap amps generally, and also specifically by doing things like cutting the clipping diode (on the Vox Pathfinder) and upgrading to higher quality op-amps. I have an aversion for working with mains voltage, so I've restricted my tinkering to pedals so far
      Awesome. Also thought of modding mine a bit. Wanted to mod the channel switch to switch with a pedal instead of pressing it.
        yeesh. all this is way over my head (sticking my hands in where circuitry goes, if you will), but i gits the general idea. so to speak. you won't catch these shaky hands anywhere inside an amp, let alone near a soldering iron. if i have work as needs being done, i'll take it to a pro.

        i'd be interested to know how that amp (in its original state) would have responded to something like my p90-euipped gt. probably still a little muddy, but p'raps not so much as with dinkum humbuckers? anyhoo, like i said, i stay away from the fiddlin, so we'll never know. all i do is buy the stuff stock, and play it stock.

        can't say i've ever switched so much as a pickup. but watching and listening to all y'all talk about this stuff is one of the main thrills i have in this here forum.

        tinker on!
        dh|
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