Author Topic: Fender champion 600 EQ + master volume mod  (Read 2520 times)

RADIATION

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  • Posts: 3
Fender champion 600 EQ + master volume mod
« on: August 05, 2011, 12:23:32 AM »
Hi everyone, I'm new here... 8)
does anyone have a circuit diagram to add an EQ and a master volume to a Fender champion 600?

like the one in this video:
http://www.youtube.com/watch?v=cIsQZyIKvGg


PRR

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  • Posts: 7453
  • Maine USA
Re: Fender champion 600 EQ + master volume mod
« Reply #1 on: August 05, 2011, 12:39:54 AM »
The parts for the classic Fender tone controls are ON the new-"Champ 600" circuit board.... but instead of pots it has fixed resistors.

Master volume ahead of the poor 6V6 is equally simple.

There's tons of Guitar Amp forums where such mods are already discussed.

RADIATION

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  • Posts: 3
Re: Fender champion 600 EQ + master volume mod
« Reply #2 on: August 05, 2011, 01:05:01 AM »
not trying to be rude or anything, but could you show me a link to one of those forums?

because seriously I've searched all over the internet and I cant find a single webpage about this mod...

thanks

waner

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  • Posts: 29
  • Sweden
Re: Fender champion 600 EQ + master volume mod
« Reply #3 on: August 05, 2011, 04:51:51 AM »
Hello

Here is a link to the schematic:
http://support.fender.com/schematics/guitar_amplifiers/Champion_600_schematic.pdf

You could put in a standard Fender EQ after the first tube.

Cheers
Mattias

PRR

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  • Posts: 7453
  • Maine USA
Re: Fender champion 600 EQ + master volume mod
« Reply #4 on: August 07, 2011, 12:05:17 AM »
> a link to the schematic:

Thanks.

> You could put in a standard Fender EQ after the first tube

It _IS_ a "standard Fender EQ after the first tube". They just replaced the pots with fixed resistors. (And drew it badly.)

Open this large image: http://i.imgur.com/HwxwZ.gif

It shows the "Champ 600", the real Champ with Bass/Treb knobs, and the snazzy Twin with Bass/Mid/Treb knobs.

From Champ AA764 to Twin AB763, they made the 15K bottom resistor "M" adjustable to trim the mids. (It is also smaller, 0-10K instead of 15K fixed, because the Twin should never be as mid-heavy as the cheap Champ.)

Now look at the "600". Where the others have 250K Treb pot, it has 180K+75K. This is just like a 255K pot jammed at 30% resistance (about 7 on 0-10 audio taper). Where the others have 0-250K Bass rheostat, the "600" is stuck on 75K (again, like 7 on the knob you don't get). The fixed Mid resistor is taken directly from the original B/T Champ; but could as well be a 25K or 50K audio-taper pot.

Master volume just means (generally) replacing the 220K fixed in front of the 6V6 with a 250K "Volume" control, just like it has at the grid of V1b. This will reduce gain. At some point it will limit output power. Meanwhile it is wasting away what little NFB the AA764 has, so it gets less polite.

> a single webpage about this mod...

I don't know of anything specific to the "600". This is *general* Fender guitar amp design and tweaking.


trancedental

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  • Posts: 180
  • London England
Re: Fender champion 600 EQ + master volume mod
« Reply #5 on: August 08, 2011, 12:15:11 PM »
not trying to be rude or anything, but could you show me a link to one of those forums?

because seriously I've searched all over the internet and I cant find a single webpage about this mod...

thanks

Try the www.sewatt.com forum, they have all the Champ, Valve Junior & other single ended amp, advice & mods for these amps. You just have to register

RADIATION

  • Member
  • Posts: 3
Re: Fender champion 600 EQ + master volume mod
« Reply #6 on: August 09, 2011, 10:52:58 PM »
thanks everyone, sorry for the late answer but I was out of town


 

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