Twin Boost Notes
In this video, I did a little run-through of the Twin Boost and the different bits and bobs it could do.
The Twin Boost was the first pedal I designed. It was two single transistor boosts, and the idea was that when you stacked them and changed the direction, you could make a dual transistor, fuzz-face-ish overdrive/fuzz kind of thing. The original design had both sides quite clean, but I changed it up a little bit for more variety.
Clean Sound Context
I started with the clean sound, because it was helpful to contextualise what was happening. As soon as I pushed the volume, I started driving into the amp, so “unity gain” settings sounded quite subtle.
Right-Hand Side (Cleanish Boost)
The right-hand side was a fairly simple, cleanish boost.
With the volume levels kind of matched and the gain down low, it gave:
a bit of a bass cut
a bit of an upper mid boost
a little bit of texture
Pushing the volume drove the amp more
The gain knob gave gain from the pedal circuit rather than the amp
Combining gain + pushing into the amp was super dynamic
I put my modded Nobels ODR-1 in front briefly just to get a bit of texture
Overall it did that nice bluesy bit - simple and good fun.
Left-Hand Side (Fixed Gain + Bias)
The left-hand side didn’t have a gain knob in the same way - it had fixed internal gain.
With the bias knob all the way up, it got closer to the right-hand side sound (a bit more full range)
It still cut off some low end to help it cut through
The gain texture felt different: more grit, more texture, less “classic overdrive”
Turning the bias down starved the bias more
It got quieter, so I compensated with the level
Using the volume as a boost added that extra texture
It was like the biasy fuzz sound I liked, but on a cleaner platform. I liked it for an interesting rhythm part.
The Toggle in the Middle (Order / Stacking)
In the middle, the toggle determined whether internally:
the right-hand circuit went into the left, or
the left-hand circuit went into the right
When I did that, I ended up with roughly the same topology as a two-transistor fuzz (one going into the other). The volume control on the first stage acted like how hard I was hitting the second transistor, making it drive more.
The toggle pointed to whichever one was first.
Both On Together (Fuzz-ish Territory)
With both on together, I was stacking the two.
With the settings I had, the two low cuts added together, so even more low end got taken out
It got quite loud and quite gainy
The gain was coming from the pedal itself because the volume slamming into the other volume was quite high
It definitely got into fuzz territory
When the left-hand side was second, it retained the majority of its character.
Flipping the Order (Different Feel)
When I flicked the switch, the roles changed:
One side became the input gain control
The other became master volume
That put it more into high overdrive / distortion territory rather than fuzz, but the bias still flavoured the sound a lot - especially depending on whether it was second in the chain or not.
I also noticed it became a feel thing: the main sound stayed similar, but under the fingers it felt much more compressed because of what was effectively going into it.
Turning the volume right down proved what was clipping was the pedal circuit rather than the amp.
Takeaways
The right side was a simple, cleanish boost with a bass cut / upper mid boost / light texture
The left side was more about fixed gain and bias texture, from “normal” to starved/biasy
The toggle made it behave more like a two-transistor stack, fuzz-face-ish in topology
Switching order changed which side dominated and changed the feel under the fingers
It stayed super dynamic, and it covered a lot of ground depending on how it was stacked
At the end, I said I’d quite like to try one day building a Twin Boost where each half used the kind of layouts you’d see in a fuzz face setup - basically leaning even further into that two-stage idea.