fuzz... BASS fuzz!!!!

 This is a drawing of AionFX's "Penumbra" project - which is an amalgam of the best parts of the Zvex Wooly Mammoth bass fuzz and the Vexter series Mastotron.

BUILDER'S NOTE!!! The "pinch" control is shown here as it is laid out on the AionFX schematic. However, that will make the gate close as you turn the knob counterclockwise. I don't like this, so in order to wire it so that the knob works in the 'proper' (clockwise) direction, swap Pinch 2+3 to the pad where 1+2 currently is. Then swap Pinch 1 to the pad where 3 currently is. The gate will still have the same threshold - the knob will just increase the gate as you turn it up instead of down.

It's basically a silicon fuzz face with no low end loss. Bass guitars, synthesizers, whatever - it all sounds awesome coming out the other end of this beast. 

The transformer and jfet form a switchable "pickup simulator" (designed by Jack Orman) that tricks the fuzz circuit into thinking it is the first pedal in your signal chain by mimicking the impedance it would get directly from the output of your guitar pickup. So that you don't necessarily have to keep it first in your signal chain.

The "pinch" control is a really simple, REALLY effective noise gate that clamps down and releases fast.

As always - if you want something neater than stripboard, you should head over to AionFX and buy a PCB or kit from them. Aion's kits were how I got started making circuits - and I managed to make their HM-2 project work back when I barely knew which end of the soldering iron to hold... Their build documentation is super thorough and laid out in a clear and sensible way.

BUT if you still wanna take a swing at this one, just know that I have yet to build this up. So until I decide to pick up my iron again, this one is UNVERIFIED as of the posting date of 1/27/25.

EDIT: this layout is posted over at Dirtbox as well, and was just VERIFIED AS OF 3/14/25 by Magus Fremar!!!

Boooooring... but SUPER useful utility circuit: an active buffer+signal mute with optional boost and dedicated tuner out

 First post in a few months since I've been busy building a "DAW-less" rig to make sequenced/electronic music with. I'm also deliberately taking time off from soldering, since I use leaded solder and probably have more of the stuff in my blood than I should after 4+ years of almost daily circuit building.

BUT since I am currently having to build quite a few of these things (seven in total) to properly mute all the channel strips on my mixer (some of them pop when I feed them too hot of a bass signal), I thought I might share my layout.

This is, essentially, a standalone active mute switch with an optional dedicated tuner output. I adapted it from a GuitarPCB design, and if you fancy something neater than stripboard, you can buy kits from Müsikding or PCBs directly from GuitarPCB.

This drawing includes some suggested modifications from GuitarPCB - most notably, the gain boost pot - which can be omitted and replaced with a simple jumper for just slightly above unity. The 470nF capacitors are my preferred values for maintaining low end integrity. The original build doc calls for 220nF caps in those four positions.

Any dual op amp will do - TL072's work fine. I've been using NE5532's in order to keep it clean and safely allow for the jump to an 18v supply (just use caps that are rated to a minimum 35 volts!).

You can also use a 3PDT stomp switch, of course - but only two columns of lugs are necessary - which is why the drawing is for a DPDT stomp.

The original build doc calls for a common-anode, bi-color LED but I've no experience with those, other than I have read that they can be kind of on the dim side. I've got horrible peripheral vision and need my LEDs to be visible from space, so I went with two standard 5mm diodes for separate active and mute indicators.

Also - if you don't want the dedicated, always-on, tuner pedal out - you can just omit the polarized 2u2 capacitor, as well as the cut that is just to the right of the cathode of that cap. One less 1/4" jack to solder!

The original goal of the designer of this circuit was to allow you to still use your tuner while totally removing it from your signal path. While replacing it with a decent, modifiable buffer/signal driver. As it is designed, the tuner is always on and pitch detecting - you just choose whether or not you want your signal active or muted.

It's a pretty simple utility build that works great, with NO popping or signal bleed. It's definitely in the "I didn't realize how badly I needed one of these until I built it" category for me.