OAM VB-2

The first release of the OAM VB-2, in textured white with dark brown knobs.

VB-2 manual

Controls

Volume. There are two of them. 1 comes before 2. This means you can try a whole lot of things. Try turning the 2nd volume all the way up, and only changing the 1st volume (leave the Bias controls all the way down for now). See how that impacts the sound. Then try turning the first all the way up and play around with the 2nd one. What we are doing here is playing with two crucial controls which could also be called Input/Output, Pre/Post, Gain/Master. The first gain stage cascades into the second. The second volume can always be used as a master volume control. Same as with an amplifier, turning the master all the way up will give the greatest amount of headroom (dynamic range). If you want less volume and more gain, you can turn the master volume down (2) and the input volume up (1). This concept applies to many things (plugging a phone into a stereo system, finding the correct levels for recording, finding the sweet spot on a guitar amp, etc. etc.), and is worth getting a really good grasp on.

Bias. There are also two of these. The first one controls the bias of the first transistor. The second controls the bias of the second transistor. Easy enough. What’s really going on here is we are changing the resistance (and therefore the current) on the emitter side of each of the transistors. When we change this value, the voltage on the transistor changes, and therefore the cut-off and saturation points change as well. If we wanted to be really nice to the transistors (and our ears) we would find a nice safe spot in the middle between cut-off and saturation so that the signal didn’t clip or cut out or sputter or do anything weird. However, I have a feeling you might want to try some other things with them. By changing the bias, we are essentially changing the gain as well, so turning up the bias knobs will add volume and saturation. Turn them up high enough and the transistors will start gating and getting extra fuzzy. Try turning up both bias controls all the way and notice that it will actually act as a noise gate. It will only allow a signal that is large enough to pass, and it will mute anything that is too quiet (the humming of your pickups for example). 

Voltage. Try running it at 18V, try running it at 6V (use the sag control on a PP2+ for example), there are no rules (except don’t try anything over 18V!). Ok maybe try 24V but you’re sort of pushing it! The character will change dramatically based on the voltage the pedal is receiving and you may find the bias controls especially to behave differently and to start gating at different positions than they did before. In general, the higher the voltage, the lower the bias control will need to be to start gating. If you change to 18V and you don’t hear any sound coming out of the pedal, turn the bias controls down, and it should return. Always make sure to pay attention to polarity when you are trying out different power supplies. A center negative supply should always be used or you risk damaging the pedal.

For a clean boost, try these settings (18V)
(V1 middle, B1 all the way down, V2 all the way up, B2 all the way down)

For an overdrive, start here (9V)
(All controls to 2 o clock)

For a gated fuzz, let’s try this (9V)
(Bias all the way up, volumes at half)

Now that we mention fuzz, I should also mention an important aspect of this pedal which will have a great effect on how it sounds. This pedal has a low input impedance similar to your favorite fuzz pedals. It’s one of the things that gives it its smooth, dark breakup and pleasing fuzzy goodness. However, if you are finding your tone to be too dark and muddy, try using a buffer before this pedal. It will brighten up the character of the pedal quite a lot. If you’re on the side of turning all the knobs up and you think it sounds too harsh, try the opposite and remove any buffers before this pedal and place it in the beginning of your chain (yes even your trusty TU2). Another thing worth trying, when plugged directly into the pedal, is turning the volume down on your guitar and experimenting with the pedal turned up. Since the impedance increases as you roll the volume back, it will brighten up and give it more chime, and you have a whole lot of gain on tap from the volume knob on your guitar. This interaction I find to be very special and unique.

The key thing here, if you haven’t caught on yet, is to try things! There is no right or wrong, there is no better or worse, only you can decide what you like and what works for you. Also, there may be settings in which you will find the pedal screaming back at you in defiance with annoying high pitched squeals. We could have fixed these things, but it would have meant limiting the boundaries of what was possible with the pedal. It’s up to you to find the edge, and to go past it if you so desire. The VB-2 is a raw, bare-bones circuit, with no filters or clipping diodes added to shape the sound. Nothing that didn’t need to be there. I believe that it is this simplicity which gives the pedal its flavor, and its flaws which will make it find its place amongst the myriad options available.