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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 :-)


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Sunday 18 March 2012

Vox - Tonebender / D*A*M - 1966 / D*A*M - Superbee

The Vox Tonebender circuit ranks as one of the earliest Fuzz Pedals available. Here's some info from http://www.legendarytones.com/fuzz%20feast1.html:

"The oldest fuzz in our collection, this 1966 Vox Tone Bender was made famous by that group of British lads known as the Beatles. This unit is a simple design, uses two germanium transistors and is built, and feels like, a tank.

The sound of the early Tone Bender is a cross between a device like a Dallas Rangemaster treble booster and a Fuzz Face. At maximum fuzz settings, it has a little bit less fuzz than an early germanium-equipped Fuzz Face. In addition, the frequency response curve and output of the unit emphasize the upper frequencies more so than any Fuzz Face, whether germanium or silicon. The resulting tone when cranking up the fuzz control (appropriately labeled “Attack”) is a very raspy-sounding fuzz that is very pronounced and aggressive on the top end. In some applications such as using it against a brighter amplifier, the Tone Bender may be considered a bit much for the ears to take as it can easily be made to sound like a piercing buzz saw. I suppose the Vox folks warned us with the “Attack” label however…

But interestingly enough, using the Tone Bender with a cranked up Vox AC-30 which can then produce a lot of low-end and compression courtesy a quartet of EL84 tubes, the Tone Bender makes a nice solo lead boost to use to and balances the overall tone nicely. And in another application, when using the Tone Bender through a Vox AC-30’s Brilliant “Top Boost” channel and cranking it up, the fuzz tone is very psychedelic ‘60s in flavor and buzz.

Not surprisingly, when using the Vox Tone Bender through an amp set purely clean, the fuzz tone is very crunchy, with medium gain, and again with an emphasis on a lot of mid and high-end bite."

Along with a quick demo video:

Now here are a few schematics for differing versions of the Vox Tonebender;

From Geofex.com

From Fuzz Central
As you can see there are a few differences between the two pedals so what should you do? Build one (or buy one if you are lucky enough to find one - they are as rare as hen's teeth) of these:

It's the (now discontinued) D*A*M 1966 - a super quality Vox Tonebender replica. Here's a quick (!) description from the D*A*M website:

"The D*A*M "1966" is a replica of the Vox Tone Bender that was produced between 1966-68 that features the grey hammerite casing with the large logo black face plate. Maybe the most iconic Tone Bender of all, say the words Tone Bender and this is the pedal most will think of. 
Originally made in 1966 the Vox Tone Bender had one of the longest runs of any Tone Bender variant and was still being made in some form or another into the mid to late 1970's. Even though these pedals were branded as Vox units they were not UK made items. These Tone Benders were actually made in Italy. It could have been possible that the earliest units were made in England, as with the early Vox Wah pedals, but there is no direct proof for this. The very first Vox Tone Benders did have slightly different component values but most obvious of all had an OC76 transistor in the second position within the circuit. These early Vox units were fitted with a SFT337 and an OC76 and also had the input capacitor mounted beneath the circuit board. Models from approx 1967 still used the SFT337 but in place of the OC76 used a SFT363E and featured a top mounted input capacitor.

The 1966 is usually fitted with either an AC125 or an OC71 in the first stage which ensures lower noise levels and an OC76 in the second stage to guarantee those splendid raspy fuzz tones of the original. Very special gain selected pairs are used to produce a wide dynamic response with creamy organic overtones and a strong output level. The tone produced by this circuit can be a little shocking at first if you are expecting a deep brick wall type of fuzz tone. The treble content could be considered quite high for a fuzz pedal of this type but it does make for a very unique sounding effect and an excellent pedal to be used with dark sounding British valve amplifiers. This also is an excellent device to use when you require a fuzz box that has greater articulation, clearer dynamics and tighter string definition than say a standard Fuzz Face type circuit.

The D*A*M "1966" features...

1. High quality gain selected pair of germanium transistors that are correctly set up to produce a bold clear dynamic tone with a good amount of sustain. An OC76 is just always used in the second position of the circuit. The transistor in the first position will vary depending on stock levels usually an AC125, OC75 or a SFT353 will be used.

2. High grade parts including Ero Vishay metallised polyester film capacitors, BC components Electrolytic capacitors, carbon film resistors, Audio grade Alpha potentiometers, Daka-ware Chicken head knobs and Cliff jack sockets.

3. A heavy duty UK made cast aluminium enclosure finished in a highly durable stove enamelled hammer tone paint job.

4. A unique two position rotary tone switch for numerous flavours of fuzz and tone control, from the original "wasp in a jam jar" tone to a bolder and more full bodied "Super Bee" fuzz tone

5. An easy access tool free slide out battery drawer that makes battery change overs a breeze.

6. Low noise circuitry featuring the heavy use of internal shielded cable, short signal paths and single point grounding."

Well, thanks to beedotman and Sinner (who does some of the best vero projects around!) there's a great vero layout so you can have a go at building your own version:

And, as always, a link to the freestompboxes.org forum topic if you're interested: http://freestompboxes.org/viewtopic.php?f=13&t=14831

Here's an after-addition: The D*A*M Superbee, which is a variation of the Vox Tonebender circuit with larger input and output caps:

And some lovely gut shots:

And a demo video of the Super Bee in action:

And a great layout by beedotman:

Pick your gains for the transistors. Beedotman's recommended start values are 60-75 hfe for Q1 and 75-105 hfe for Q2. Q2's collector is biased around -6 volts.

And the freestompboxes.org forum topic: http://freestompboxes.org/viewtopic.php?f=13&t=13626


  1. Beautiful wiring inside that pedal.

  2. Your articles are very informative and simply great. I've work on Fuzz Face more than 1 month. 1. measure more than 120 Ge transistors. 2. Try combinations of low and high Hfe (20-300x), low/ high leakage, Ge & Si or Si & Ge transistors, tweekig feedback resistor & T1 collector R. T1 is most important. It must be Ge, Hfe more than 250, low leakage and low Usat base to emitter. T2 can be similar Ge but can be also Si (BC550C is great). Than you can tweek Rfeedback 'till 470K and lot of fuzz & sustain. With low Hfe (20x) distortion is clumsy, weak sustain & Rfb can't be greater than 47K. With 100 or 220K you'll get negative attack. C1 can vary from 1micro to 1nano. T1 is most important for long, fuzzy sound. Small contribution. Keep on. Cheers


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