Fender Champion 600 Input Voicing Mod "Kit"

Instead of selling "kits" for the Champion 600 mods on this site, I'm putting together a series of posts with direct links to sources for the parts involved.

Below is a chart of capacitor values and -3dB points for the Champion 600 low input revoice mod.

This mod will work in a great number of amps with high and low inputs including the 5E1, 5F1 Champs and a host of other Fender Amps. You can find the the measured frequency response for a .012 uF cap in Part 2 of the mod post.


Clicking on any of the capacitor values in the chart should take you directly to a suitable part for the mod on the Mouser Electronics website. You can order directly from there.

If you have any questions about the parts links here, feel free to drop me an email.

Fender 5E1 / Champion 600 Coupling Cap Mod "Kit"

The stock capacitor in a Fender Champ 5E1 and 5F1 circuits is .022uF. This allows a great deal of bass through the circuit and the cap is frequently changed to restrict the low end and make the distortion a bit less muddy.

If you'd like to try changing this cap you can use the chart below to help select a value. In case you have trouble finding a place to purchase caps of the right value, each of the cap values in the chart has a link directly to a suitable part on the Mouser website.

Just click on any of the values and you'll see how it works.

The values in blue indicate that the cap values are in microfarads (uF). As the values get smaller I've switched to picofarads (pF) indicated in black.

If you are a bit foggy on the meaning of different capacitor values, see the capacitor values post.

The capacitor values here are good for a stock 5E1 Champ or a 5F1 Champ with a cathode bypass cap on the first stage (the frequencies shift a bit if that cap is not present and stock 5F1 champs don't have the bypass cap).


They'll also work in place of the tone stack in a Champion 600.

Fender Champion 600 akavalve Mods

Since the blog format is a bit awkward to navigate through, I thought I'd make up a table of contents for my Fender Champion 600 Mod posts. First are the essential safety posts and then the mods listed in order of difficulty with the easiest ones first.

Discharging the filter caps:

Part 1
Part 2



Tube Upgrade:

New preamp and power tubes


Input Voicing Mod

Part 1

Part 2
Frequency Response Measurement

Input Mod "Kit"
Cap values for different frequency response and
Mouser Electronics Parts Links.


Presence Plus Mod:

The Presence Plus Mod
The Presence Plus "Mod Kit"


Cathode Bypass Mod

Part 1
This one includes a couple charts for bypass cap values
and their frequency response for both
the stock circuit and the Frondelli mod.

Part 2
This is the installation of the mod.
It uses large cap values
but smaller ones detailed in Part 1
could easily be substituted.

Part 3
This shows the measured frequency response
with the four different settings of the
cathode bypass lift described in part 2.


Tone Stack and Fat Boost Mods

Tone Stack Test

Installation Details and Frequency Response Graph

Explanation of the Fat Boost Mod resistor values

Tone Stack Bypass Cap Values (same as 5E1 Champ)


The 12DW7 / ECC832 mod

Part 1

Part 2


Miscellaneous:

Animated GIF of the disassembly

A look inside the chassis

Stock Speaker response measurement

Comparison of the Champ 5E1 and 5F1 schematics

Stock Output Transformer Measurement


I'm pretty sure that's all of them.
I'll add new ones to this list as I post them.

Fender Champion 600 Presence Plus Mod Kit

I've had a number of requests to provide kits for the mods described here. The components are generally quite simple - it's finding the sources and actual part numbers that may give people some trouble.

So instead of bagging up components, figuring out how to price them and sending them out, I'm going to try to provide links to Mouser for the exact parts needed for each of the mods.

This post is for the Presence Plus Mod.

If you're not making it switchable, the only part you need is the 16uF capacitor. Here's the link to the part on Mouser's website.

This is a lot easier for me than trying to make up "mod kits" and mailing them out. And it's cheaper for anyone interested in doing the mods too since you won't be paying for my time in the price of the kit. Let me know if it works well for you.