My Fender Champion 600 Mods

Fender Champion 600 Modifications

The Fender Champion 600 amplifier is a great little recording amp, but in my experience the stock unit is not quite good enough. The reasons for this are mainly personal taste, but one or two I believe are big factors in getting a useable recorded sound out of it.

First of all, here are the mods I made to my Champion 600 and then I’ll go into more detail:

• Replaced preamp and output tubes.
• External speaker cabinet for recording.
• Modified the circuit (voids warranty!).

Replacing the Tubes

This part is simple and non-destructive. It is also fun if you like scrutinizing sounds, which I do!

As soon as I took delivery of my Champion 600 amp and plugged it in I knew it could benefit from new valves. The ones that came with it sounded pretty poor to me. I went straight on Ebay and had a look around for good-quality output tubes.

Of course I didn’t know which of the two tubes in this amp (one 12AX7 preamp tube, one 6V6 output tube) was influencing the sound the most, but seeing as I like to turn the volume up high I started by buying a replacement for the output tube only. Remember, this is a cheap amp, so part of the fun for me was to improve it without spending too much money. It seems crazy to spend the same cost as the amp again to make it sound better. You might as well buy a better amp to start with!

I found a pair of NOS Brimar 6V6′s on Ebay in the UK and they were a crazy price. Something like £10 for the pair. I only needed one and incidentally a friend of mine had bought a Champion 600 the very same week as me, so I gave him one as a gift. I noticed a difference right away with my Champ. Noticeably better. Fatter, warmer, rounder and with some extra midrange, which made it seem louder. It was much less of a harsh sound. My friend thought it was a great improvement too.

Modification number one then was a success – £5 for a "real" output tube! Bargain.

With a step up in sound such as this I decided it was worth locating a better preamp tube too, but first I remembered I had an old valve Fidelity tape recorder from about 1960 lying around and not working properly. It had a 12AX7 in it and it was an original Mullard – Great, one of the best valve brands ever made. Unfortunately it was well past it’s prime and it didn’t sound that great. It had a nice tone, but it crackled a lot and was obviously close to becoming a deceased valve!

I found an original Brimar 12AX7 on Ebay and it was more expensive then the two 6V6′s I had bought previous – about £15 I think. After the positive Brimar experience I had with the 6V6′s I bought the 12AX7 (ECC83) and again experienced an impressive step up in tone quality. This actually was more noticeable difference to me.

Summary: Well worth changing the tubes. There are only two of them, so it’s cheap and fun.

External Speaker Cabinet

I thought about replacing the speaker in the amp and I may do so in the future, but this will be just for messing around. For recording I wanted a truly pro speaker and was still conscious of keeping the modification cost down (mostly for the challenge and, again fun!). Fortunately I already have another amp: A Fender Princeton Recording Amp. Seeing as this already has had an upgraded speaker, a Tonetubby Alnico 10" (My absolute favorite guitar speaker), I thought I’d try it through that.

It’s not a perfect match because the Tonetubby is an 8 ohm speaker and the output of the Champion 600 is 4 ohms, but it safe to use. I think the result is that the volume of the amp is a little less than if the impedances were matched. It sounds really great through this speaker – In fact everything sounds amazing through this speaker. It’s expensive, but worth every penny in my opinion if you are serious about guitar tone, especially in the recording studio. The 10" Tonetubby has as much sonic girth as a 12" speaker with the detail of a 10".

The best way I can describe the benefits I get from using this Tonetubby speaker is to use the following analogy:

It does for my guitar tone what a quality tube mic preamp and analogue tape do for digital recording. It takes off so much harshness and presents you with so much clarity, you can actually listen to the top end. The sound doesn’t fly at you like a beam of treble! It goes around you so you can listen to it rather than have it thrown at your ears.

Bottom line, try out a few speakers or just go to your favorite one. A bigger speaker will make the Champion 600 sound like a bigger amp.

Circuit Modifications

This was the most labor intensive modification and actually involved me hacking away at the internals of the amp; not too much, but it did void the warranty, which is understandable. I’m not an amp tech, but I can read instructions and use a soldering iron. I also found it fun to do this, but if it had been a more expensive amp I either would have got a professional to do the work or not bothered with the mod. at all.

There are many different after-market modifications for the Fender Champion 600 amp available now, but I went for one that seemed simple, practical and was based in the UK (where I’m from). I went for the "alnicomagnet" mod kit on Ebay, which is excellent, fairly easy to fit and comes with a really good instruction guide on CDROM. This modification does a few things:

• Greatly reduces hum.
• Sorts out the voltage supply discrepancies for the UK-spec model
• Modifies the tone stack to 5E1 or 5F1 Champ specs (late 50′s model)
• Adds a 3 position switch for standby and selecting between Pentode/Triode operation (2watts or 5watts)

This amp is greatly improved after these simple mods and now, through the 10" Tonetubby, it can get close to a Tweed Deluxe tone – to my ears anyway, which considering the cost is a fine, fine result!

I love my Fender Champion 600. I will post some sound clips soon too. If you use an external speaker, it is a great recording amp, but I find that there is still sufficient hum audible if you close mic the built in speaker. However that may just be my amp. My friend’s Champion 600 had a better stock speaker in it, which didn’t crackle like mine does (before and after the mod).