Help with an old solid state amp

[Aleksandar]

Hello people!I have a question for those guys there that are more experienced with electronics then I am.I have this guitar amp ,SS somewhere arouund 100 wats or so,it has hi lo inputs,with no overdrive channel,which I actually dont need,'coz I have my fuzz face,and soon my DIY overdive/distortion pedal project will be finished.What botheres me is this certain bad,harsh transistor clipping(I forgot to mention that this amplifier is really old and it has no opamps in it)which kind of sounds raspy and kills the sustain.Now,I'd like to smooth it out a bit so I'm thinking about inserting diode clipping circuit in it(LED's for example just to have things little bit more compressed).so whts your opinion on this ,and also in what stage of the circuit should I insert these diodes?Thanks and regards!

[olddawg]

I doubt if you can change the characteristics of that old SS amp much. A compressor might help a little. BTW, an overdrive will not do much for you but drive the amp into that nasty clipping that you obviously dislike and insert more noise. Rather than wasting your time trying to impliment the impossible I would suggest simply getting a different amp. If you want to effectively use your OD get a tube amp. Unless you are playing very large venues you do not need anywhere near 100 watts. For most clubs 18-30 watts is plenty. I have played small clubs with a live drummer and other guitarists with a 5 watt Epiphone Valve Jr and a 4X10 cab. Seriously, you can't make a silk purse out of a sow's ear, or as Frank Z said, you can't polish a turd. If you are after an extremely clean sound and use your distortion pedals exclusively for your dirt it might be usable, but you will probably find it very sterile, unresponsive, and plastic sounding. Then again, it's a personal thing. As my old friend from Chicago once said, "The milk that makes me fat might kill you."

[Aleksandar]

Wel,lets say that I kind of like the sound of that amp when played louder.The drumer in our band is really loud so it does help me a bit.The load is a 15" speaker and that adds some warmth too.But what I dislike with the amp is this kind of sufficating sound when playing lower notes!I don't know a betterway to explain this.It's like it's choking.It's not that noticebale when playing with the band but when playing alone it kills me

[Aleksandar]

Forgot to mention,when I built this little SS practice amp,I noticed the same problem when diodes are not in the circuit,but whn I put them in, the sound gets a lot finer.The thing s,that little amp involves opamp in the preamp section,whereas this huge monster uses simple transistor in it,so I'm a bit confused about where should I insert the and can I mess something!?

[PremiumPlus]

You can't just toss some diodes into a circuit and expect it to sound better. It sounds like you need a nice tube amp if you don't like the way transistors clip. If you want to change the way the SS amp sounds, get a distortion box like a Rat or one of the Boss distortion stompboxes; like olddawg said, you don't want to overdrive the SS amp because that's going to make it clip like you don't like.
I recommend going to a music store and checking out some low power tube amps.

[Enzo]

Um...


WHAT amp do you have, and HOW OLD is it? if it is all transistor - no op amps - then I'd bet it is at least 30 years old. And I further bet there are a bunch of small capacitors in it that are dried out. And I don;t mean just the filter caps.

Seriously, I bet your amp would sound tons better with a cap job.

[Robert M. Martinelli]

+1 on what Enzo says.

You stated that the amps tend to "choke" when playing loud, ( this could also be due to a poorly designed power supply of course ) and this makes me think your filter caps have developed some ESR due to aging, thus they're no longer able to act like a energy reservoir, so when you strum or play heavily the PS voltage could drop and this could make the amp clip sooner.

It's up to you, if you have the skills you can probably afford to "waste" some time and money and do something about it ( there are a lot of knowledgeable friends willing to help here, but don't expect miracles ), otherwise you'd better get yourself a good tube amp ( of a comparable output power ) as per olddawg's advice. A low power tube amp won't help, because they obviously tend to clip,( even if pleasantly ) at a lower power, giving you less headroom, and you wouldn't be able to be on par with your "loud" drummer.

Hope this helps

Best regards

Bob