What the Wah?

Hadn't done a wah in a while and thought I'd do project where you can build several old school wah circuits on the same board. Many of the early wahs back in the late 60s were based on the original Thomas Organ CryBaby, and as a result many of them follow the same topology with a few value changes. Here's the schematic:

A lot of the original transistors used have a BCE pinout, so I've made 2 layouts: one for BCE and one for the more common CBE pinouts. Generally speaking your just need transistors in the 300-400 hFE range, however with many circuits, different transistors offer different flavors. So as always, socket and experiment.

What the Wah? Project

SolaSound ToneBender Mk III

For #FuzzFriday I give you the SolaSound ToneBender Mk III. The Mark III was a smoother and less aggressive follow up to the famous Mk II Professional. SolaSound built it for several other companies–Vox, RotoSound, Park, etc. There are plenty of layouts for this classic fuzz out there already (there's already 2 on this blog), but I drew this up for a 2-in-1 box I'm putting together (this into a Catalinbread RAH) and thought I'd share. So here's a modern layout for the ToneBender Mk III. Originals used PNP germanium transistors, so the perf side reflects positive ground layout, but the PCB side shows negative ground if you want to use NPN transistors. For more info on the circuit check out this page.

Here's the drilling template for it.

Vox ToneBender Mk I

You might look at this and think, "Gee, it's just another Fuzz Face," when in actuality, this pedal pre-dates the famous Dallas Arbiter stombox. (This is different from the Sola Sound ToneBender Mk I, as the Sola Sound has 3 transistors.) It was made in Italy for Vox and sounds like a Rangemaster and Fuzz Face combined, due to its smaller input and output capacitors. This is also the same circuit as the D*A*M 1966 Italian Tone Bender. I've added a 10k trimmer in place of the stock 8.2k resistor to dial in the bias for Q2 (a 20k trimmer might give you more tweakability), but on the PCB there are pads for a resistor in place of the trimmer if you prefer to go that route. Also, I've added a pull down resistor at the input, and polarity protection and power filtering. Note that this was originally built with PNP germanium transistors and was positive ground. The perf side of the layout reflects this, while the PCB side reflects negative ground for use with NPN transistors.

Vox Treble Booster

The Vox Treble Booster was a simple silicon treble boost effect that plugged straight into an amp's input jack. It allowed the user a boost in high frequencies for lead work. I laid this one out to use as a built in effect on a guitar (hence the lack of a power filtering cap and polarity protection). Note that the 10uF cap is on its side to reduce the height of the populated board. It should easily fit in a 1590A. If you want a volume control use a 100k pot with the Out pad going to lug 3. Lug 2 becomes the Out and lug 1 goes to ground. I found that I really didn't need a volume pot though, as the effect level was right around unity.

Vox Repeat Percussion Tremolo

This cool little effect was originally housed in a small box that plugged directly into your amp (which you then plugged your guitar into) and later on some of Vox's higher end guitars. You'll need to track down an obsolete 2N2646 unijunction transistor for Q1, but they can be found on eBay or Small Bear. It produces a thumpy sounding tremolo that could be really useful if you're trying to cover The Who's "Baba O'Riley" and need to do the intro on guitar.

Here's the stock version:

And with an added depth control:

SolaSound Tone Bender Mk. III

Smoother sounding than the Mk. II Professional, the Tone Bender Mk. III not only added a tone control, but the circuit was a deviation from earlier Tone Benders. Q1 and 2 create a Darlington pair that amplify the signal, while Q3 is what creates the fuzz. I've laid this out for negative ground operation, so make sure to use NPN transistors. Q1 and 2 can be low gain silicon if you don't want to use germaniums. Q3 could also be silicon, but a germanium is most likely going to sound best. You can also reduce the value of the 220k resistor (or just replace with a jumper) between Tone 2 and Volume 3 for more output.

Here's a compact layout:

The original TB3 had a cool way of mounting the pots to the circuit board (see pic below). This approach was later emulated by Ross with their Distortion, Compressor, and Phaser pedals, and ProCo with the RAT. 

Since I'm a sucker for eliminated offboard wiring, I created another layout (PCB only, sorry) inspired by the original, but updated for more modern components (like radial electrolytic caps and 16mm pots) and to fit in a 1590B or 125B.

And a shot with the components not in "outline" mode.

This has an optional 1M resistor between the base and collector of Q3 if using silicon transistors.

This layout can also be used for the Vox ToneBender Mk. III and the 3-knob Park Fuzz. See Fuzz Central for component changes.