Twin Boost update work (first day 2026)

9 Jan

It was my first day back doing pedal stuff after Christmas/New Year (I’d been back teaching and doing bits in the evenings).

I’d been working on revised versions of the Twin Boost + Embers Fuzz (the two pedals I launched Hamilton Effects with just over a year ago).
After a year of feedback + living with the production models, I had a few things I wanted to revisit at the start of 2026.
A lot of notebook time went into switching headaches, especially on the Twin Boost (I didn’t want to spoil too much yet).

I demo’d it quiet first (volume low) so you could hear what the circuit was doing without it just being “boosted amp sounds nice”.
With normal bias (bias effect “off”) it was slightly gritty.
When I dug in, it had that squish — not quite compression, because it stayed really dynamic, but it was a feel thing (and that’s why I like bias control).
Compared to bypass it had less treble, still clarity, just less.
Turning volume up boosted an AC30 model, and obviously it sounded really nice… but that’s why I showed it quiet first.
In the new Twin Boost I said I was going to include the attenuation switch from the Twin Parallel, so you could get back down to pretty clean.
As I brought in the bias knob (starving the transistor of voltage):
- volume lifted a bit
- texture/crunch came from the circuit (not just the amp)
- it added drive + compression but kept clarity
- sharp attack stayed (T-style pickup transient still came through)
- pushed far, it got quieter again so I compensated with volume
- it didn’t feel like “overdrive/distortion”, but it was still gritty and fun
- it was the kind of texture I listened for for rhythm parts

That was where I landed for the revised left side.

I added a buffer before either boost because for parallel mode the split needs to be buffered.
That created some of the switching headache, because you can choose whether 1 goes into 2 or 2 goes into 1 — but I wanted both boosts to sound good after the buffer.

I rebuilt the right side around a few different transistors (I didn’t have any 5088s to hand, so I started with a 2N3904).
I tested input cap values:
- 22n set the high-pass before boost
- I tried 100n (more bass through)
- It was subtle, but I ended up leaning toward 100n so bass/baritone players could use it too.
I tried different transistors:
- BC550C felt a bit hotter / biased differently (almost like “two layers” of drive / asymmetrical-ish feel), but I wasn’t convinced it was worth swapping for.
- 2N2222A was way higher gain and I preferred the tone — clearer, less muddy.
I found a resistor was limiting the top end of gain rather than the bottom end.
I added the same 22k input resistor I’d used on the left side, and that cleaned up the super low-gain “sizzle” nicely.
I also tested the clipping diode setup:
- I preferred it how I already had it (with that extra diode to ground to soften it a bit) rather than straight hard clipping to ground.

I ended up happy with the right side using the 2N2222A, the input gain calmed similarly to the left side, and the same clipping diode layout as the left.
I didn’t have the right gain pot so I couldn’t test the full gain range, but it felt like a solid updated circuit plan for the next round of Twin Boosts.

James Hamilton

Fuzz Transistor Shootout