Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Please login or register.

Login with username, password and session length
Advanced search  


Pages: [1]   Go Down

Author Topic: Yamaha G100 Head distortion and foot switch  (Read 91 times)


  • Chipper
  • *
  • Chip Points: 0
  • Posts: 3
    • View Profile
Yamaha G100 Head distortion and foot switch
« on: April 14, 2017, 08:05:29 AM »

 As I am fairly new to DIY and electronics I have uploaded the schematic to my Yamaha G100. I'm hoping someone can help me out by telling where the distortion section is and what type of distortion is used and is it mod do able. I find the distortion fully cranked very weak and going clean with different combos of a DS-1, ross comp., a cheap overdrive and a cheap blues breaker style. So far Im diggin the DS-1 into a Nuxx OD-3 (now when I go through my little fender Bullet using the Bullets distortion and these 2 pedals it screams (and I LIKE a LOTTTT) but much weaker and blatty using the Yamaha. I figured they are both solid state could I get the fender distortion sound from the yamaha?

  Also I've been scouring the internet trying to find out the wiring for the footswitches. Can any body help e out here? Maybe draw up a schematic of how I am to wire one up. Like mono or stereo plugs? Latching or non latching switches?  momentary or non switches? I have the skill to do fairly good modding and building just lacking the ability to really understand and comprehend the whys and hows of electronics. Building kits and diy ing is 1 thing but total comprehension of a schematic is a totally higher level IMHO 


  • Legendary
  • ******
  • Chip Points: 171
  • Posts: 1564
    • View Profile
Re: Yamaha G100 Head distortion and foot switch
« Reply #1 on: April 14, 2017, 11:16:46 AM »

Your schematic covers four different G100 models, plus there are still a number of others.  What exact model do you have?  G100?  G100 II?  G100 III?  And 112, 212, 210, 115?

Of the two you presented, does one really match your amp?  Note the upper on has the whole preamp on one board, whwile the lower one has the clean channel on a smaller separate board.

Yes, the circuits are VERY similar, but we need to be accurate.

The AB footswitch is just a common off/on stomp switch, wires need not be shielded.  The reerb is also a common on/off stomp switch, but it is connected to the signal path, so it MUST be shielded wire.

TR101 has a pair of clipping diodes across its gate for distortion.

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Chip Points: 413
  • Posts: 4034
    • View Profile
Re: Yamaha G100 Head distortion and foot switch
« Reply #2 on: April 16, 2017, 01:07:46 AM »

Agree and add
I figured they are both solid state could I get the fender distortion sound from the yamaha?

Hey !!! they are both cute, have 4 legs, tail, paws, whiskers, glow in the dark eyes,  they are both felines!!!!

I think I will get inside that cage, ... after all ..... what could go wrong?  :loco :duh

Short answer: get a *good* distortion pedal ... or two if you feel particularly wicked  8| , and plug them into your loud killer Yamaha.
Pages: [1]   Go Up

* User Info
Welcome, Guest. Please login or register.
Did you miss your activation email?
* Recent Posts
Jordan Professional 440 Solid State IC Amp Head by teemuk
[April 27, 2017, 07:58:53 AM]

Strange amp in a suitcase by J M Fahey
[April 27, 2017, 05:42:47 AM]

DIY Layout Creator by DrGonz78
[April 26, 2017, 08:40:13 AM]

Marshall Lead 100 MOSFET 3210 Head by J M Fahey
[April 26, 2017, 12:59:30 AM]

More differential amplifier questions by phatt
[April 24, 2017, 09:05:25 AM]

* Sponsors