The Function F(x) Professional MKI Mini Fuzz is a compact germanium fuzz pedal from Function f(x), built around three 2N404 germanium transistors, which Guitar Pedal X notes the maker's Dave "tends to favour"1. Guitar Pedal X listed it among the best new fuzz pedals of 2020 at a price of $169 USD1.
What it does
The Professional MKI takes the Tone Bender MKI circuit, a three-transistor fuzz design, and fits it into a mini enclosure suited to crowded pedalboards. The maker describes it as "a pedalboard friendly version of my MKI Fuzz, with a few expanded features"2. It uses three 2N404 germanium transistors, which Guitar Pedal X's Stefan Karlsson noted the maker "tends to favour"1.
Its three controls follow the classic MKI layout:
| Control | What it does |
|---|---|
| Fuzz | Sets the amount of fuzz distortion |
| Level | Sets the output volume |
| Q3 Bias | Adjusts the bias of the third transistor, shaping the fuzz texture |
Guitar Pedal X called these "my favourite minimum fuzz controls - Fuzz, Level, and Q3 Bias"1.
What reviewers said
Guitar Pedal X reviewed the pedal twice, in its 2020 roundup of the year's best new fuzz pedals and again in its 2022 selection of mini fuzz pedals. In 2020, Stefan Karlsson wrote: "The Mini Professional MKI just sounds incredibly authentically a MKI - perfect for that Mick Ronson sound"13. In the 2022 mini fuzz roundup he described it as "an incredibly version of TB MKI fuzz"3.
"The Mini Professional MKI just sounds incredibly authentically a MKI - perfect for that Mick Ronson sound"
For players exploring other fuzzes from the same maker, Function f(x) also makes the Clusterfuzz Jr., the Cannon Dual Fuzz and the Octavus, and the broader field is covered on the Fuzz Pedals page.
Sources (3)
- Guitar Pedal X, Guitar Pedal X, 2020-12-18
- Fuzz | R2R Electric, R2R Electric
- Guitar Pedal X, Guitar Pedal X, 2022-04-26






