D*A*M: Grand Magnus Orbiter (incomplete trace), Tag Board Layout

It's a Tone Machine / Arbiter Doubler - let's get that out of the way up front. Here's the thread on the D*A*M forum for the Grand Magnus Orbiter

Rainy day project for me, as I already have a Tone Machine that I'm happy with.  Not sure I'd ever be up for a two-layer tagboard layout… The D*A*M Grand Magnus Orbiter is something special in that regard.

This is also an incomplete trace as the second tag board is not visible - which also happens to include the tone control. I'd be surprised if Dave Main didn't tweak it somehow.  Personally, I think a larger cap in the tone stack to increase mid-range might be a distinct possibility - not unlike tweaks made to his Fuzz Sounds for a beefier sound.

The only significant change I noticed on the top board is the 10u cap on the emitter of Q, so it's a bit hotter at the start.  Silicon diodes are used on the top board in the octave section, which usually provides better (or at least different) results to germanium.

I'm assuming that if anyone builds this, they'll be an experienced builder, so I've left a few things that I might normally include off the layout.

D*A*M GRAND MAGNUS ORBITER - TAG BOARD LAYOUT

Photo care of Reverb.  

Looks like 100k sustain pot

LTSPICE 

This is the difference with the 10uf cap on the emitter of Q1 - basically, things get square right from the start, and there's an increase in level and a slight change in the frequency response.

Now we see the response at the output - assuming stock values were used on the Grand Magnus Orbiter.  As mentioned earlier, I'd be surprised if this was left stock, and like the Big Muff, the Tone Machine tone control is easy to mod and shape to your taste.  A standard mod is to increase the size of the 3n3 capacitor to lift the mid scoop.  Even a small increase to 4n7 makes a difference.   Another mod is adding a 22k resistor after the 3n3 capacitor, which makes it much more like a BMP tone control and dramatically increases the scoop.

This is the bass and treble sides of the tone control.

 

And finally, an output trace.

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FOXX / AION: Tone Machine / Vulcan

After recently finishing a mojo size / vintage transistor Tone Machine that has been sitting on the bench for way too long, I decided to do a regular layout, as the practicality of some of my other layouts for the Foxx is probably not for everyone (maybe even me in retrospect).

So I've done a standard Foxx with the Aion Vulcan mods, and then took the Vulcan mods a step further by using a rotary switch for the mids.

By changing from an SPDT switch to a 2-pole rotary for the mids on the Vulcan, the optional 22k resistor in the tone stack can also be switched in and out.  So instead of three different mid-range options, you now have six, including a stock Tone Machine setting.

The rotary switch looks like this on the schematic.  

Unlike the Aion Vulcan, the rotary switch does not sum the capacitors (placed parallel), which is why there's a 3n3 on the rotary in place of the 2n2 on the Vulcan.  This also provides a bit of room to move in the selection of the 1n capacitor.  While 1n provides a sound of its own, it could easily be a little larger - maybe a 1n5 or similar.   I’d even suggest keeping the 3n3 and the 15n and pick a value in between to replace the 1n.  Maybe a 6n8 or a 10n.  

FOXX TONE MACHINE / AION FX VULCAN - VERO LAYOUT

FOXX TONE MACHINE / AION FX VULCAN - LTSPICE

You can get an idea of the stock response and the range of the Aion Vulcan with these.  100% Sustain, Tone swept from 0 to 50% and 100%.

Adding the optional 22k resistor into the tone stack increases the mid-range scoop, similar to a Big Muff.

The standard Foxx TM uses a lot of 10u caps, whereas the Vulcan’s uses 1u - it makes zero difference to the frequency response.

 

FOXX TONE MACHINE / AION FX VULCAN ON THE SCOPE

Start your device at low levels - this uses a straight sine wave.   

 

This is it sweeping through the six-tone settings, with the tone being turned from bass to treble on every setting.  The first three are 1n, 3n3, and 15n with the additional 22k resistor in.  The last three are 1n, 3n3 and 15n without the 22k resistor.  The second last one is a stock TM.

 

Diode switching - in, out and octave.  Note the changes to the harmonics

FOXX: Tone Machine, BE Mods 2026

Updated Foxx Tone Machine layout on 0.15" vero.  This was inspired by the 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. 

I've tweaked a few values to suit my taste - this is not a stock Tone Machine.  

FOXX TONE MACHINE - BE 2026 V1

ADDITIONAL FOXX TONE MACHINE INFORMATION

Credit where credit is due - most of this information is from Aion build documents, which are excellent (go buy a kit, it will be easier than this...)

Transistors

The earlier Blue FTM used 2N3565 transistors with a hFE of around 230 to 245.   

The Red FTM used 2N3565 transistors with a hFE of around 450 - 550 

*I've also seen BC237B listed on the JD Sleep schematic from 2002.  

Treble Capacitor 

The earlier Blue used 3n3.   The Red used 2n7

Tone Control

Yes, it looks a bit like a Big Muff.   Can add a resistor after the treble cap to ground for BMP-like results.

The 4k7 resistor on the bass side of the treble control limits the range of the pot - jumper or remove for a tiny bit more range on the bass side.  

And of course, there is the mid-switch - basically adding more capacitance to the 3n3 treble cap, to boost mids.  I like a little bit of this action, but not too much.  15n is too much for me...  

Q3 bypass cap

Noted as 10uf on the schematic, measured at 22u, which does make a small difference to the bass response (more).  Basically, a 10u cap that is out of spec.

Additional Resistor

Red version had an extra 12k series resistor before the sustan pot, shaving a bit of level off.

Diodes

Use matched diodes in the octave section - originals used generic 1N34A diodes.  Matching just gives a better octave.   

Coupling Caps

Apart fromthe 100n on the input, the original used 10uf coupling caps.  They can be trimmed down to 1uf with no discernible difference.  

Optional Extras

The CBS Arbitier Doubler has a 10uf bypass cap on the emitter of Q1 - but is more gain here really needed?

Can add a 22u cap on the emitter of Q4 to bring the level up, as it can be a bit low.  

FOXX: Tone Machine

One of my favourites - the Foxx Tone Machine.  I've posted a couple of layouts, one stock, the other is the Aion FX Vulcan.  The Aion FX mods make the Foxx even better - I prefer it with the mid switch mod.  

The mid switch mod really gives this circuit a lot more range.  The diode switch is also interesting - with the octave off, one diode remains in the signal path.  The diode switch bypasses this diode for a slightly different sound.

Apart from the 10uf from Q3 to ground, all other capacitors can be replaced with 1uf electrolytic or poly caps.  Might save some space, or maybe you prefer polys over electrolytic in the signal path.

My only disappointment with making the Foxx, is that I can't replicate the incredibly seventies looking velour stompbox enclosure.

FOXX TONE MACHINE - VERO LAYOUTS

Or something a little more traditional in terms of size and where the wires leave the board.  I could have made the board smaller, but I was going for something with plenty of room around components.  

FOXX TONE MACHINE / AION FX VULCAN - VERO LAYOUT

Read the build docs on Aion FX for the Vulcan to find out more.

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

STOCK FOXX SCHEMATIC

FOXX ON THE SCOPE

This is straight from the first boost stage