my champ modding thread

[j9fd3s]

i bought this fender vibro champ years and years ago, and while its neat, it sorta just collected dust. the amp sounds nice, but its too clean, and the vibrato makes me sick. amp dates to 1978, the speaker is a 10" from some other fender.

i guess i was bored the other day and printed out all the champ schematics i could find, and started comparing. after really looking at it for a while (i can do cars, but amps are kinda weird), i decided to remove the tone control circuit, and then the vibrato circuits, like an earlier champ, i also pulled out the feedback wire.

i guess i did it differently than most people because i completely removed all these things, and most people bypass the tone controls by just using a resistor to make them not effective... also i guess most people change the feedback resistor instead of removing it altogether, or something. its been kind of neat to play in there, so some of this stuff might go back in or get modded later....

anyways the results! i wish i had some sound clips, the amp went from this very clean fendery (you could dime it and not piss of the neighbors) to LOUD, it kind of barks now. and its loud, did i mention it was loud? @2.5 its louder than it used to be @10! its still kind of boxy and directional so i'm not done yet

 

[zzmoore]

Re: my champ modding thread

NFB is usually a pretty easy call. You try it both ways, and then go with what you prefer. The bigger amps had a "ground switch" that made a good NFB switch after the 3 wire power cord is installed
A Lot of guys install a Tone Pot that also has a switching function. That way, you can switch the tone stack in and out of the circuit as your guitar-music-room-style... demands.
At any rate...looks like you found your way through this. Nothing you did is hard to replace, so it is good all the way around..!!!
Hard to tell from the pics...if your Elytics are original,it is past time to renew those.
Nice Amp
best

 

[j9fd3s]

Re: my champ modding thread

thanks! yesterdays experiment was to hook up a 12" celestion that my brother has floating around, and OMG what a difference! it has this really natural sounding distortion, and at a much lower volume too. i'm not sure the amp really liked it much, its supposed to have a 3ohm load, and the celestion is 16...

so i think i need a speaker.

i guess i'm looking to get the amp to really sing, but hopefully at a reasonable volume, and right now its actually too loud, kind of raucous and boxy, so i think i will be playing with the bypass, and the tone controls actually might go back in too, although i might mess with the frequency range they adjust.