Author Topic: 20 Watt amp has too much distortion when Gain Pot set to 1 and Volume at 2.  (Read 230 times)


  • Chipper
  • *
  • Posts: 1
  • Chip Points: 0
    • View Profile
El Cheapo Chinese amp has Gain and volume as well as 3 pot equalizer. It has a push switch to select overdrive or normal. The Volume operates OK when overdrive off. The Volume is a B50K Pot.
Plays sweetly when not overdriven. Clear highs and lows.
When I select overdrive, there is no tapered increase as I turn the gain up. It goes straight to muddy distortion, with less and less clarity as the gain is increased, just more fuzz.
It has Led clipping and the leds light up when overdrive is selected.The Gain Pot is a C100K.
There are 2, 8 pin pre-amp and an amp ic,s. (Can't read op-amps Id).
What I want is more control of gain with a taper from a light beginning to full.
Use it for Electric Acoustic and a Les Paul. No heavy dark stuff, (Ideally, my full on would be around half of normally used overdrive).
Got it as a freebee, almost new. Prepared to tinker. Nice little amp for practice.
Should I be looking at reducing the 25 volts into the pre-amp? (how should I do that)?
Looking for a solution. (and where it should be in the circuit).
« Last Edit: July 18, 2019, 02:47:00 AM by charlescazaly »

Jazz P Bass

  • Elite SSGuitarist
  • *****
  • Posts: 150
  • Chip Points: 12
    • View Profile
Kind of difficult to help without a schematic.

IF the gain control is in the feedback loop of an op amp, you may be able to tone it down with a larger potentiometer value.


* User Controls

Welcome, Guest. Please login or register.
Did you miss your activation email?

* Recent Posts

Gallien Krueger 800RB by phatt
[Today at 02:22:45 AM]

Kay 708 amp repair by Jazz P Bass
[August 19, 2019, 08:30:07 PM]

National GA920P Schematic by mwdavis
[August 19, 2019, 06:55:01 PM]

Pearce A3 schematic by epeirce
[August 19, 2019, 10:16:50 AM]

[August 17, 2019, 10:19:25 PM]

* Sponsors