Vox Tone Bender On Stripboard

Here’s the Vox Tone Bender, a great early fuzz pedal that’s sure to please.

The build I’ve done here is the NPN version of the pedal, so it’s slightly different from the original, which used PNP transistors. The big difference here is that this NPN layout allows for negative ground, putting inline with the what’s standard these days; this will work with the 9V power adaptors you’re used to.

The other addition to the original Tone Bender build is the inclusion of a trimmer potentiometer coming out of collector of the second transistor. This was an addition made by Tagboard Effects (where I got the layout). This allows you to adjust the bias of the transistors and therefore the overall gain and therefore fuzz level. Older circuit designs like this often used transistors that you just can’t get anymore, so adjusting the trimmer pot will help you tweak and dial in the exact sound you’re after.

If you like fuzz, Vox’s Tone Bender is a great choice. Like so many fuzz pedals, this one is a good choice for beginners, which is why it’s on my easy DIY guitar pedal builds list. Give this a shot as an early build.

Jump to stripboard layout.

Vox Tone Bender Wiring Schematic

Check out the wiring schematic for the Tone Bender.

And here’s the bill of materials.

		Notes
R1	1M
R2	47k
R3	10k
R4	820R
R5	1K

C1	100nF
C2	15uF	22uF can be used here instead
C3	47uF
C4	4.7nF

Q1, Q2	2N5088
P1	1K Lin	Attack potentiometer
P2	50K Log	Level potentiometer
P3	10K trim

Jacks, power supply, etc.	Don't Forget	The stuff you usually use.

If you’ve built or seen fuzz circuits before, this will look pretty similar! But hey, it works…

One important thing to note here is on the transistors. As mentioned, this is the NPN version of the original circuit. Changing it up to NPN makes it so that this pedal design conforms to modern power paradigms. So, if you wire your power supply the usual way, this circuit will work. In addition to that, I’ve used 2N5088, which is a good transistor for all around use. I’ve read that the AC176 may be a better choice here, especially because it’s a germanium transistors, but these can be harder to come by. The 2N5088 may be an uncreative choice in transistor, and I may be losing some tone in this build because it’s silicon, but it works and the 2N5088 is easy to get.

Plus there’s the trim pot that let’s you adjust the gain a bit, so even if you can’t get the right transistor, you can adjust the pedal a little bit.

Another pointer on this circuit is that the 15uF capacitor for C2 can be replaced with a 22uF. A lot of other circuits use 22uF capacitors, and I always have a few of them handy. 15uF capacitors aren’t used as often, and, for this build, I forgot to buy any! C2 is just an output capacitor, which stabilises the current and voltage, so it shouldn’t affect the tone due to the change.

Feel free to also play around with:

Add tone control. I found the Tone Bender a little bit heavy on the bass; it sounds great, but if you want a bit more treble, tone control may be the way to go.
Try different transistors. This will change up the sound of the pedal greatly. There are a lot of choices to play with!
While you have P1 and the trim pot to adjust the gain for Q2, Q1’s bias isn’t adjustable. Try something different for R3, or even chuck a resistor going to ground below Q1!

Vox Tone Bender Stripboard Layout

As mentioned, fuzz pedals generally don’t use a lot of components, and the Tone Bender is no different. This makes the stripboard layout for it pretty easy! You can see that come of the components are a little crowded in the first half of the board, but they’re actually not hard to solder; it’s a bit of a squeeze on the top of the board, but not on the bottom!

This is the layout from Tagboard Effects, but as usual, I’ve provided both a layout with component numbers and with values, just in case you want to change something up.

Here it is:

My Experience Building The Vox Tone Bender

This was a super cruisy guitar pedal build. Fuzz circuits are usually fun and simple builds.

As the time of writing, I still haven’t settled on the level for the trim potentiometer. This thing sounds fantastic (more on that later). The trim pot takes away some of the gain, which can be a good thing. I’m trying to decide whether I want a lot of fuzz or something that lets some subtlety through. I’m always tempted to dial things to 11, and that’s fun, but I usually end up backing things off a fair bit.

A future build of this may replace the trim pot with a normal one so I can make adjustments to both. Who knows. I don’t have a lot of experience with trim pots, so it may be a good learning experience on the fine arts of biasing transistors.

How Does The Vox Tone Bender Sound?

This is a real classic fuzz. I recently made a Harmonic Jerculator which had some great tone to it, but, since the Tone Bender predates the Harmonic Percolator (which the Jerculator is based on) but about a decade, it just has that more raw sounds. And, of course, it’s very 1960’s.

I’m finding the Tone Bender a little bit bass heavy, but I wouldn’t call that a criticism. The tone is a appropriate and generally well balanced. Of course I’m just playing the pedal on its own without anything else. Adjust the tone settings on my amp helps a little bit, but it would probably also do well with a treble boost. But that’s just personal preference. A lot of players in the 60’s, especially British players using Marshall amps used treble boosters because amplification and effects tended to lean towards the bass a bit too much.

Like a lot of simple early pedals (and modern guitar pedals for that matter), there’s a lot that you can do with the Tone Bender that doesn’t involve adjusting the pedal itself. Lowering the guitar’s volume (and therefore the input signal into the pedal) takes away a lot of the distorted aspects of the sound without changing much of the organic feel to it. Pickup selection also does quite a lot to change the sounds coming from this thing.

I tested this pedal with my Stratocaster into a solid state Orange amp, I haven’t tried it with humbuckers yet, so that may change things up again.

I quite like the Tone Bender, and I’d like to play around with this circuit a bit to see if I can add anything to it.