The ZVEX Silicon Fuzz Factory 7 Mod is a limited-edition fuzz pedal from ZVEX, released in August 2018. It takes the Fuzz Factory 7 and swaps out the original's NOS germanium transistors for PNP silicon ones1. Everything else carries over: the same knobs, the same nine-position rotary tone switch, and the same footswitchable Tone circuit1.
The point of the swap is character. According to ZVEX, the silicon transistors produce a "brighter, tighter and more synthetic-sounding" fuzz than the germanium version1. Guitar.com described the underlying Fuzz Factory 7 as "a box of noise disguised as a fuzz pedal"1, and Gearnews called this silicon variant a "dirty velcro synth fuzz in a box" that "can do all sorts of chaotic fuzzy tones"2. Where the standard Fuzz Factory 7 leans on vintage germanium warmth, this version is aimed at players who want a different tonal variant of the standard circuit, one that ZVEX positions as tighter and more aggressive3.
A brighter, tighter Fuzz Factory with silicon transistors
The Fuzz Factory circuit underneath this pedal has a long history. Aion FX describes the topology plainly: it is "essentially a classic Fuzz Face with a LPB-1 booster in front of it, but with the twist that half of the components" are replaced with knobs, giving fine-grain control over the transistor bias5. That bias control is what lets a Fuzz Factory go from a normal fuzz to gated, sputtering, velcro-ripping territory.
The choice of transistor is the whole story of this particular mod. The classic Fuzz Factory and the standard Fuzz Factory 7 use germanium transistors; this version uses gain-paired PNP silicon3. Gearnews noted that ZVEX says the silicon diodes make for a "brighter, tighter and more synthetic-sounding" fuzz6, the same language Guitar.com quoted at launch1.
"According to ZVex, the silicon diodes makes for a 'brighter, tighter and more synthetic-sounding' fuzz."
The controls
The Silicon Fuzz Factory 7 Mod keeps the full control set of the Fuzz Factory 7. Gearnews lists "the regular six knobs to control Volume, Gate, Comp, Drive, Stab and Fat," plus the nine-position rotary switch2. Guitar.com adds that there are "six other knobs to govern parameters such as compression and feedback" alongside the Volume control1.
| Control | What it does |
|---|---|
| Volume | Overall output level2 |
| Drive | Gain into the fuzz circuit2 |
| Comp | Compression character12 |
| Gate | Noise gate, from open to fully gated sputter2 |
| Stab | Stability of the transistor bias2 |
| Fat | Low-end thickness2 |
| Nine-position rotary | Toggles between fat and reed-thin sounds via preset tone stacks12 |
| Tone footswitch | Footswitchable circuit that mellows out the high frequencies1 |
The nine-position rotary is the Fuzz Factory 7's signature feature. Rather than one tone knob, you get a switch that chooses between fat and thin sounds via preset tone stacks2, which Guitar.com describes as toggling "between fat and reed-thin sounds"1. Gearnews later counted "that preset Tone stack with 7 distinct settings on tap" in its roundup of boutique fuzzes6; the two publications count the positions differently, so treat the exact number with that in mind. The footswitchable Tone circuit is the escape hatch: when the silicon transistors get too bright, it mellows out the high frequencies on demand1.
Fuzz Factory 7 lineage and limited run
As a limited edition, it was never a permanent catalog item. It retailed for $499 at launch in August 20181, and ZVEX's Mod Bench page for the Silicon Fuzz Factory now lists it as sold out14. Players who want the silicon Fuzz Factory sound today are looking at the secondhand market for this mod, or at the other silicon versions in the range.
Questions
What is the difference between the Silicon Fuzz Factory 7 Mod and the standard Fuzz Factory 7?
The Silicon version swaps out the original's NOS germanium transistors for PNP silicon ones. According to ZVEX, the result is a brighter, tighter and more synthetic-sounding fuzz. Otherwise the two pedals are identical, with the same control set, nine-position rotary switch and footswitchable Tone circuit.
What does the nine-position rotary switch do?
It chooses between fat and thin sounds via preset tone stacks. Rather than a single tone knob, the switch gives you nine fixed voicings that range from reed-thin to fat, so you can jump between preset character settings while the other knobs handle gain, compression and gating.
Does the Silicon Fuzz Factory 7 Mod use germanium or silicon transistors?
It uses PNP silicon transistors, replacing the NOS germanium transistors of the standard Fuzz Factory 7. Silicon transistors are less sensitive to temperature than germanium, which is one reason makers build fuzzes around them.
Is the ZVEX Silicon Fuzz Factory 7 Mod still available?
It was a limited edition released in August 2018, priced at $499, and it is not a regular catalog item. ZVEX's Mod Bench page for the Silicon Fuzz Factory lists it as sold out, so finding one now means the secondhand market.
Who designed the Fuzz Factory?
The Fuzz Factory circuit was designed by Zachary Vex, founder of ZVEX Effects. The circuit is the basis for the whole Fuzz Factory family, including the Fuzz Factory 7 and this silicon-transistor variant of it.
Sources (6)
- ZVEX launches Silicon Fuzz Factory 7 Mod, Guitar.com, 2018-08-03
- ZVex Silicon Fuzz Factory 7, gearnews.com, 2018-08-07
- Silicon Fuzz Factory, ZVEX Effects
- ZVEX introduces the Russian Fuzz Factory 7, Guitar.com, 2018-08-14
- Flare Fuzz Machine / ZVEX Fuzz Factory, Aion FX, 2021-03-19
- Top 5 Boutique Fuzz Pedals of 2018 by Mr Black, ZVex, Beetronics, KHDK, Earthquaker, gearnews.com, 2018-12-31
