Dunning ∿‌‌ Kruger FX

Effect Pedals and Guitars, etc.

Extra Medium

Now With More Medium

In the overlapping portion of the Venn diagram depicting people who have built their own guitar amplifiers and people who have seen This is Spinal Tap, I doubt that there are many who haven’t considered making the knobs go to 11. It’s an undeniably great joke, and it has an aura of being a secret handshake among musicians (even though that movie came out in 1984, and not in secrecy). I know that I’ve had to tamp down that instinct every time I’ve built an amp. But if I have acquired any wisdom in my decades of adolescence, it’s that we should not be limiting ourselves to a dichotomy: many people may ask whether the amp should go to 11 or not, but few ask if the 5 should be really big. That’s Extra Medium.

I can’t actually take credit for the name Extra Medium. Once, while on a brief intermission from unemployment, I came to know a group of software developers. When starting to build a new website, they would have to set variables for font sizes, like small, medium, large, etc. Invariably, over the course of the project more sizes would be required, which was fine as long they could just keep adding “extra” to an existing size, like extra-large or extra-extra-large. But sometimes, new sizes would need to get crammed in between existing sizes, which could require extra work or creative naming. One developer was faced with a barrage of such requests, and in her frustration, turned to extra-medium as a solution, which became immediately legendary.

Extra Medium is in the lineage of one of the most standard and ubiquitous guitar pedals, but throws in a few twists for that little touch of “extra.”


Extra Medium uses the Feathers circuit, designed by dylan159 and released under a Creative Commons license. It’s his re-interpretation of an EQD Plumes, which is their re-interpretation of a Ibanez Tube Screamer.

The Tube Screamer is one of the most successful pedals of all time, and has been copied, modified, and held up as an inspiration for countless other pedals over the years. It’s a soft-clipping overdrive that doesn’t really produce a ton of gain, but can be used as a boost to push the front of an amp in a way that many find pleasing. It also has an EQ curve that pairs well with some common guitar/amp combinations and can help a guitar cut through a mix.

The EQD Plumes is a departure in that it replaces the standard op-amp in a Tube Screamer with a JFET op-amp, adds a charge pump for more internal voltage and headroom, and has diode options for the clipping section. dylan159’s Feathers is a simplified version of that, which gets rid of the buffers, the charge pump, and adjusts some values. Extra Medium is built exactly to the Feathers spec, although I put the clipping diodes on a footswitch instead of an on-off-on toggle, so it doesn’t have the “no diodes” functionality.

Vital Stats

Cascading Style Sheet Jokes
Ultra Extra


In practice, I find Extra Medium to have more gain than my OG TS9 Tube Screamer and possibly less mid hump, although I didn’t put it on a scope or anything and it might be in my head. The tone control is a little bonkers, and is really only functional between 0 and 10%, which is likely an error on my part and not a feature of the circuit. It is extremely dynamic, and will react strongly to how hard the strings are played. In the following quick example, there is no knob manipulation in the first half, neither on the pedal nor the guitar—I just started off fingerpicking, then light picking, the dug into it more, and it goes from clean to rather filthy on a single setting. The second half of the clip is just some dumb power chords and wanking. It’s all the Emomaster into a Deluxe Reverb with some delay.