Welcome to the Revolution

Hi there, welcome to my blog - La Revolution Deux. It's an odd name - but I like it! Here you will find all the info on my various DIY Guitar effects builds, amplifiers and guitars. Everything from a humble Ibanez tubescreamer to the holiest KLON Overdrive.

You may also find a few effects builds that I am looking to move on - usually in exchange for other effects/gear/cash. You can always check my ebay account to see what I've got up for grabs.

Have fun, enjoy the blog - Fred Briggs :-)


Feel free to get in contact with me about anything you see on this blog or with any general questions about guitars, amplifiers and effects, I'll be happy to answer! Just click the button above to email me directly or alternately my email address is fredbriggs2007 [at] googlemail [dot] com

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Sunday, 12 February 2012

Colorsound / Sola Sound Tonebender MKII Professional

The Sola Sound/Colorsound Tonebender MKII Professional is probably the second most famous Fuzz box after the Fuzz Face. It's a three transistor fuzz circuit that creates an unholy amount of gain and sustain. For an idea of how it sounds - Jimmy Page used one with his Dragon Telecaster from the Led Zeppelin 1 era, yes, it's THAT tone. Sola Sound also produced the circuit for Vox, Marshall and RotoSound. These units were named the Vox Tone Bender Professional MKII, Marshall Supa Fuzz and RotoSound Fuzz Box. For a really detailed history of the Tonebender series of pedals check out this:  http://www.stompboxes.co.uk/History.html from David Main of D*A*M (A guy who really does know fuzz boxes!).

[an original Marshall Supa Fuzz]

[three original Vox Tonebenders]

[a Tonebender MKII circuit with Mullard OC81 germanium transistors]

Here's a 1968 advertisement:

And here's a receipt for Jimmy Page's Tonebenders from SolaSound!

And here's a video of the D*A*M Tonebender MKII Professional in action, I think you'll agree it sounds pretty mind/ear/sense destroying:

Now here's the schematic. Here you can see the three transistor layout. As with any simple fuzz circuits the transistor type and gain is a huge factor in deciding the overall tone of the unit. It's recommended that the gain of Q1 ~ 70hfe with Q2 ~ 70-90hfe and Q3 ~ 100-120hfe. I've built many Tonebenders with many different type of transistors. Always use a germanium transistor for Q1, then you can experiment with low gain silicon transistors. Experiment and have some fun, you'll certainly find a decent fuzz tone or two! For some more detail on exact circuit operation and mods visit: http://fuzzcentral.ssguitar.com/mkII.php

Here's a PCB layout available from Tonepadhttp://www.tonepad.com/getFile.asp?id=86


1) http://www.led-zeppelin.org/joomla/studio-and-live-gear/312
2) http://fuzzcentral.ssguitar.com/mkII.php
3) http://www.stompboxes.co.uk/History.html
4) http://theheliopolisofblossius.wordpress.com/2011/06/12/tone-bender-mkii-build/


  1. hey,

    what i found is that the 100k pulldown at the input makes a tremendous difference to the available gain (and possible harshness). I read that the OC81Ds were fairly low gain (lower than you described) and had the 100k, whereas the OC75s were higher gain (probably within the "perfect" range) and had a 10k. Try your tonebender with a 10k, it will tame it alot and make the whole range of the fuzz control more useful. then adjust to taste, 20k, 50k, etc...


    1. This comment has been removed by the author.

    2. i think this schematic needs a coupling cap between q1 and q2??

  2. missing a coupling cap between q1 and q2???


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