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Fender Champ 12 mod
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It appears MR. Torres has retired due to illness according to his web page he is no longer selling mod kits. :-(
I wrote asking to purchase the instructions to the champ 12 RK and bias mods and no reply.
Can somebody who has bought the kits in the past post the instructions, since they are no longer for sale?
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The description was more interesting than the actual mod , you're not missing much!
google champ 12 mods , here's one that amounts to changing caps in the cathodes and tone stack , Haven't tried it
https://www.premierguitar.com/articl...ender_Champ_12
It would tough to change the basic architecture of the overdrive though, seems a " budget " amp all in all
best thing about mine is the snakeskin cabinet [ which was 1/4 too narrow to fit my super champ into ! ]
A few posts up joeM has found a modified schematic , which seems to get rid of a few caps and increase a couple of resistance values
without really considering it, you'd think it reduces gain & some brightness, I'm sure that schematic could have been written better.Last edited by okgb; 07-26-2017, 06:24 PM.
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Actually, a helpful fellow on a certain 'Tele' forum sent me the link. Out of curiosity I installed it and........
It is cool! Alot more volume on the clean channel and the headroom stays the same. I didn't notice much difference to the gain channel.
I use the amp clean so more clean volume is a real plus as that channel use to have about 1/2 the available volume as the gain channel, now they are about even.
So, now that its installed and actually sounds better, can somebody explain what exactly was done and how it acheived more clean volume? [inquiring minds want to know]
I'm ok with posting the PDF as they are no longer in buisiness.
Torres mod-
file:///C:/Users/Uzivatel/Downloads/Torres%20Tone%20mod08122017.pdf
schematic-
http://www.thetubestore.com/lib/thet...-Schematic.pdf
Also, I do have one issue with my amp that is just a little annoying. When turned on it switches to the high gain channel for about 5 seconds, then back to the normal clean channel that I have the footswitch set for. I'm thinking one of the switching vactrols is going bad but those vtl5c3/2 things are not cheap! Its really just a minor annoyance in an otherwise perfect [for me] amp. I put a jensen p12n in mine, removed the cardboard spring reverb and put the guts in a short Belton box and moved it to the bottom of the cabinet [where reverbs belong.] I also changed the electrolytics from 100uf to 220uf as they needed changing anyway. I'm done with this amp as its really sounds great, but if I can locate the source of that switching problem I would feel better about taking it to a gig.If it decides to stay in the gain channel I'd be screwed!Last edited by czech-one-2; 08-17-2017, 09:55 PM.
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Originally posted by czech-one-2 View PostTorres mod-
file:///C:/Users/Uzivatel/Downloads/Torres%20Tone%20mod08122017.pdfWhen the going gets weird... The weird turn pro!
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UH....Oooops
file:///C:/Users/Uzivatel/Desktop/To...2017%20(1).pdf
You gotta love the ''The amps circuit board is completely inaccessible to any of us'' lineAttached FilesLast edited by czech-one-2; 08-18-2017, 09:19 AM.
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Originally posted by czech-one-2 View PostSo, now that its installed and actually sounds better, can somebody explain what exactly was done and how it acheived more clean volume? [inquiring minds want to know]
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Originally posted by Dave H View PostOn the clean setting there's too much attenuation between V1 and V2 which reduces clean volume. With a Strat I couldn't get the clean setting to break up even strumming hard with everything on 10. The mod increases the gain of V1, V2 at lower frequencies (by paralleling the cathode resistors with larger value capacitors) to make up for the excessive attenuation.
So, you did the mod and had similar positive results?
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Originally posted by czech-one-2 View PostThanks for that. Why would Fender choose to attenuate the clean channel so drastically?
So, you did the mod and had similar positive results?
It was a long time ago. I didn't know about that mod back then. I think I increased the value of R18.
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''The amps circuit board is completely inaccessible to any of us''
Right, so he can't even pull the circuit board out to change parts ? what he is doing or suggesting is to put resisters and caps in parallel with whatever cathode resister and cap is in there
the cathode circuit will always have a resister as part of the bias of the tube and the formula of gain , and often a cap that increases the gain but at a frequency for cutoff related the the vale of cap,
[ smaller the cap , less gain at lower frequencies and seemingly brighter ] any resister in parallel will be less than the value of the lowest resister, so lower value more gain , add cap more gain.
read about any " pro's " using his service ?
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Originally posted by okgb View Postread about any " pro's " using his service ?
How do you think HE got famous?
EDIT: from a 2004 magazine article:“This is an area that’s nowhere near explored,” said Torres, a low-key engineering craftsman whose customer list reads like a Who’s Who of guitar players, including Carlos Santana, the late John Lee Hooker and surf music pioneer Dick Dale. “There’s a lot to dig into as far as concepts to make these things work better.”Last edited by J M Fahey; 08-30-2017, 02:53 AM.Juan Manuel Fahey
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Well, I beleive he is on his death bed or terribly ill so I'm not going to bash him. Especially since the mod actually acheived the results I was hoping for!
Anyway, thanks for explaining the 'why's' of the modification you guys. If there was a way to acheive the same results by changing some values on the pcb I would have prefered to go that route, but all in all it was a worthwhile modification to my Champ 12!
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Fair enough , let's keep it positive
and you CAN change the parts on the pc instead , just add up the resistance values [ resisters in parallel will always have a value lower the the lowest resister of the pair , caps in parallel simply add up to the sum value ]
drag is all the pots have to be unbolted to get to the pcb that's all
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