Fender Champ 12

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Guitar Desire, Sep 28, 2005.

  1. Guitar Desire

    Guitar Desire Active Member

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    Hi, I'm wondering if anybody knows if the Champ 12's(87-91)overdrive is all tube or does it have diode/IC clipping too?

    Thx:) Graham
     
  2. michael30

    michael30 Gold Supporting Member

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    Tube as far as I know. It sounds like crap. Torres Engineering makes a pretty useful mod for bringing down the gain on the lead channel. They'll send you a tone mod as well if you buy it. Forget about installing that one. I've got a Champ 12 that sounds pretty good, but I had to change a lot of stuff (speaker, tubes, baffle, reverb tank, gain pot) before it did.

    Michael
     
  3. FrankW

    FrankW Member

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    That's funny, because I just came home from a rehersal where they had a Champ 12, which I had never seen before, and I thought it sounded great with the gain-channel cranked!
     
  4. michael30

    michael30 Gold Supporting Member

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    One man's trash is another man's treasure. The thing that I didn't like about the gain channel in its original form is that "cranked" began slightly under 2 on the control. The clean channel sounds cool, sort of vintage Fenderish while the gain channel has more of a hi-gain metal sound. Both sounds have their uses, but they're too different to be in the same amp. The trick is to install a larger-value pot on the gain channel to control the amount of gain. Of course if you like either the clean or the hi-gain sound as it is and are satisfied with one sound then that's OK, but then the channel-switching ability is sort of wasted. The thing that bugged me with my standard Champ 12 was that it had the potential to be a great amp but wasn't. It is now though, after a lot of mods.

    Michael

    :dude
     
  5. Guitar Desire

    Guitar Desire Active Member

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    Thanks for the input Micheal.What is the value of the stock pot and the replacement?

    BTW My mother is a fin-bun

    Graham:)
     
  6. michael30

    michael30 Gold Supporting Member

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    I don't remember the values exactly. They're not standard size pots. The easiest way to do the mod is to buy Torres Engineerings kit (RKP New Fender Red Knob Champ pot replacement Kit). He'll send you a tone mod kit as well. Don't use it! The tone control on the Champ 12 is best left alone.

    Michael
     
  7. conrad

    conrad Member

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    I have with a broken speaker, what's a good and affordable speaker replacement for these ?
     
  8. tone junkie

    tone junkie Member

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    try a Weber Alnico 12-S speaker.
     
  9. zombiwoof

    zombiwoof Supporting Member

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    My brother has one he bought new when they came out. Sounds awesome for a little amp, and came stock with an STR Phillips 6L6GC. Maybe that tube has to do with the good sound. I don't know why I hear all the bad rap on these amps. Does anyone know if they are cathode-bias like the old Champs?

    And they are all tube, no IC distortion there.

    Al
     
  10. HipKitty

    HipKitty Silver Supporting Member

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    I had two of these...a new one when they first came out and a second one that was used. Both had the Phillips/Fender STR 6L6's. The first one I kept stock until I was talked into trading it....and subsequently regretting that move....so later on, I picked up the used one for dirt cheap. That one I modded the tone section, changed to speaker out as well as v1. I never used the tape input/output, so that got cut out of the second amp.

    Looking back, the modded one sounded superb in comparison (in my mind) to the stock unit. In fact, it sounded great!

    As far as cathode biasing like the old Champs...yes, they are cathode biased, no, not the same way that a Blackface is designed.
     
  11. Dos XX

    Dos XX Member

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    What tubes are you you using in your Champ 12s? Thanks in advance for your answers.
     
  12. HipKitty

    HipKitty Silver Supporting Member

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    Change R15 from 2.7K to 1.5K and C8 to 25mfd/25vdc is a good start...also use a higher gain 12ax7 like the TungSol 12ax7 or TAD 12ax7c for v1 and v2...the same thing can be done for R24/C12 and R36/C18
     
  13. zombiwoof

    zombiwoof Supporting Member

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    That "touchy" gain pot has been a problem with modern Fenders for many years, and continues today. In the Hot Rod amps, the fix is to put in an audio pot instead of the linear one they have stock, or to use one of those "volume boxes" or a volume pedal in the loop. On a mod page, they suggested that Fender was trying to impress young players with how loud the amp would get on a low setting, but it definitely makes it hard to dial in the amount of gain/distortion. The Super 60 run of amps has the same problem.

    Al
     
  14. HipKitty

    HipKitty Silver Supporting Member

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    So true....plus the quality of the pots makes a huge difference as well. What's in most mass produced amps with pcb-bound pots are cheap in quality.
     
  15. megabutter

    megabutter Member

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    The ressurection of a dead thread!! ooohhhhhmmmm!!

    So, I'm trying to rework one of these little *koff* gems. I've done my reading up and tore into it. This one looks to have 1M Audio pots in all the volume positions already.

    Given what we've read here, what gives?! And any other ideas for the distortion channel? It doesn't look like chip or op amp distortion, so why does it sound so crappy?

    Any more ideas would be totally awesome.
     
  16. MIM#1

    MIM#1 Member

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    Necro Bump just to rid the inter-web of bad/mistaken advice.
    The gain pot is already 1meg as you noted...so you cant raise the value! Besides, the point is to lower the gain. I think the 'Torres' mod swaps the gain pot for a much smaller 250k....
     
    Last edited: Sep 21, 2017

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