Vibrochamp Trem Mod Question

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Rick1114, Apr 22, 2015.

  1. Rick1114

    Rick1114 Member

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    Hi Everyone,

    Been on a Vibrochamp modding tear lately. Added a NFB pot (pulled the out the RCA jack for the footswitch), and added a mid pot (pulled out one the inputs) and stuck that there.

    Anyway, I would love to add a push-pull pot for the vibrato (to act as a vibrato kill switch) as I heard it can suck tone. I do like having it as an option though, so the push pull idea is better that just killing it. But I have no idea how to wire it up and my search on the interwebs has yielded very little. Does anyone have idea how i should wire it up? From what I understand it would probably be the intensity pot which is 25k. Any help would be appreciated!

    Best regards,

    Rick
     
  2. smolder

    smolder Gold Supporting Member

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    It's pretty simple, but also not terribly helpful on a 5 watt amp. You simply swap the intensity pot out with an spst pot and route the signal to one of the back tabs, and the from the second back tabt o the pot lead. Frankly, the added gain was hardly noticeable, and I put mine back to stock inside of a week.

    Though putting a 6L6 in a VC is awesome.
     
  3. Rick1114

    Rick1114 Member

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    Thanks!
     
  4. zenas

    zenas Member

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    Have you tried the tweed mod? I forget how it goes now but it lifts the tone stack and gives it more of a tweed Champ grind. As I recall the vib still works.
    Been a long time since I messed around modding a trashed VC. That one went to my brother and got rewired into a 6g2.
     
  5. mark norwine

    mark norwine Member

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    You heard wrong.

    Don't waste your time / money.
     
  6. Blue Strat

    Blue Strat Member

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    To elaborate a bit, the "suck tone" theory applies to larger Fender amps with a tremolo "bug", not the circuit in this amp or Princetons.
     
  7. Rick1114

    Rick1114 Member

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    OK, thanks. FWIW, the NFB and Mid control were both great mods for this particular amp. Eventually I might replace both with fixed resistors if I find I'm not adjusting much even when switching guitars etc. My GA-5 always sounded better compared to the VC, but I prefer the the BF sound to the tweed mostly. But the VC doesnt really sound like its bigger brothers, so Im just trying make it sound a little more likje a PR or DR. Now it's much closer to that sound than it was before.

    I might try a few more things, but right now the circuit is stock, I just added variable resistance for NFB and Mids. I guess I could just disconnect the trem just to see for myself what happens. Might also try lower the plate voltage going to the preamp. These are just thoughts for the future. Amps sounding pretty good right now though. The chime is there but bass is lacking, even for the 8in speaker. The GA-5 has much more bass, enough so you dont feel like you are really playing through a practice amp. The VC still has almost none.

    Thanks Rick
     
  8. smolder

    smolder Gold Supporting Member

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    I'm not a huge GA-5 fan, mine lacks good definition at the treble end. I really like the bronco I have... The big game changer was dropping in a (very earned hyped) Jupiter 8" speaker. It's a single ended amp, not likely to sound just like a Princeton or deluxe, but they don't sound alike either.
     
    Last edited: May 2, 2015

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