FOXX: Tone Machine / Aion Vulcan, 0.15" Vero Layout

I quite like the Foxx, and for some reason today I felt like revisiting one, but this time going a little large.  

Layout below - not that anyone else is likely to want to build an oversized Tone Machine on 0.15" vero with 1w resistors (some standing), and leads popping out all over the place.  It's almost a demonstration of what not to do with a layout for some people.

I'm using the original glob top transistors, and a few tropical fish caps for some colour.   Pretty sure I can fit it in a 150BB enclosure (just).

This is using Aion mods - if you are unfamiliar with the Aion Vulcan, it's a Tone Machine with a modded EQ section (which is great) and an additional bypass option on one of the diodes - also a cool addition. 

From the Aion build docs - which are always excellent:

The Vulcan is faithful to the original, but with two added modifications. First, the octave switch (normally just “on” or “off” in the original) now has a 3rd setting allowing you to bypass the series diode in non-octave mode. See build notes for more details on this. 

 

The second modification is to the tone control. The tone control of the original is somewhat similar to the Big Muff, but many people find it’s difficult to get good sounds from the treble side of the rotation. By increasing the value of the treble-side tone capacitor, it improves the usability. A switch has been added to let you choose between two different capacitors in addition to the original.

FOXX TONE MACHINE / AION VULCAN - WORK IN PROGRESS

And here it is ready for the box.  I often use a cardboard wiring jig to work from before boxing.

FOXX TONE MACHINE / AION VULCAN - VERO LAYOUT

AION VULCAN - TONE MOD

Here's what the responses look like on LTspice (distortion mode), with the tone control set to 50%.  

Increasing the 15n cap to 47n flattens the scoop, and the 1n and 2.2n can also go up a size if you prefer a flatter mid-range (not shown in responses below)

This is with the additional 22k resistor

Without the additional 22k resistor

FOXX TONE MACHINE - LTSPICE

Stock Tone Machine, no mods as a reference

Output in red, plus the response on either side of the tone pot on the distortion setting.  Mellow is blue, and bride is green.

Same again on the octave setting

FOXX ON THE SCOPE

This is straight from the first boost stage

And the version below has a six way switch for tone, as I got a bit carried away (how unusual).