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.  

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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