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Forum Home > Layout Gallery - GuitarPCB Build Documents, Mods and Tips > Colortone Overdrive - Fabricated Version

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ColorTone OverDriver

 A must have pedal! It bridges the gap between Boost, Overdrive and Fuzz.

Absolutely recreates many of the 70's tones.

This vintage circuit is based on the Colorsound Overdriver™ that was made popular for it's ability to bring body, richness and tonal dimension to a tube amp.

It can do everything from a substantial and  extremely transparent clean boost to all out fuzz!

We have added some modifications to the Original by adding a Master Volume Control as well as using modern transistors and cap values to enhance the build while making it more affordable.

Board Dimensions (W x H) 1.85” x 1.29” ca. 47mm x 33mm

ColorTone Overdrive  Demo



ColorTone Build Documents


Check the Forum for answers to many questions before posting a troubleshoot thread.

Do not miss the Easy Pedal Wiring Guide.

Namely the expansive Tips, Tricks and Tutorials section and the consolidated Crash Course Guide.

Mod #1

It is in the nature of the "original circuit" to have the Gain all bunched up at one end of the pedal. "See Photo at Bottom"

You adjust this to taste this by reducing your gain pot from 10kB Linear Taper to a 5kC or Reverse taper or perhaps even try a 2k. You can approximate a 2k by placing a 5k resistor across the outer lugs of the gain pot. Or perhaps somewhere in between depending on your taste!

A Tonmann option or Mod:

Use a 10kΩ trim pot on some vero (strip) board like this:

If you have already built the circuit,  disconnect the wire from lug 1 of the pot and connect it as the green wire in the diagram.  Connect the blue wire to lug 1 of the pot. Leave lugs 2 and 3 of the pot connected as in the original wiring diagram.

The value of P1 will be your choice depending on what you want, I would suggest a 5kΩB (linear), or better, 5kΩC (antilog) pot as a starting point.

Set the Gain Pot (P1) to 0% rotation and adjust the trim pot to give the minimum amount of gain that you require.  If you have to adjust the trim pot close to 0% rotation you should lower the value of P1  to either 2kΩ or 1kΩ and then adjust the trim pot again.

When you are happy with the results glue some non-conductive foam or other insulating material to the copper side of the vero board and then glue the vero board to the pot - something like I did to this input attenuator switch:

Mod #2

If there seems to be any Fizziness or too much high end  try a high value for the 220pf. I like 560pf, but 470pf should not only get rid of the fizziness, but possibly help with any RF, plus is helps add some needed Bass response

Also please be sure you verify the Pinouts on the Transistors you use by Googling the datasheets for them.

400-450 is a good HFE to shoot for in this build.

This is a good resource for understand Fuzz Pedals: The Technology of the Fuzz Face

Circuit Board available in the PCB Shop.

Here is a Finished Build thread:

Here is a Finished build in a Combo Pedal:

Here are some sample Voltage Readings from a working Color Tone Overdrive:

Q1 - E-.39,     B- .94,       c- 1.62


Q2 - E-.99,     B- .1.62,    c- 4.65


Q3 - E-.69,     B- 1.32,     c- 5.75


Here is a nice photo showing how tight the Boost to Gain ratio was the the original.

We have a mod to spread this ratio out for a better feel for some.

December 19, 2012 at 3:10 AM Flag Quote & Reply

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