AW: RE: [AH] Moog D.I.Y.

Haible Juergen Juergen.Haible at nbgm.siemens.de
Thu Nov 25 16:18:27 CET 1999


	>> Has anybody here ever heard of someone building their own
MINIMOOG?
	>> 
	>Our own Juergen Haible has cloned the Minimoog:
	>
	http://www.synthfool.com/diy/jh_new_picts.html

Thanks for the mention !

To be honest, I have to add this is not really a clone of the original
circuit. This was one of my first larger projects, and I did not know
much about vintage synth then. Stuff like non-standard envelope
shape, and even the influence of different VCOs, are things that
I have only learned on AH and synth-diy, i.e. too late for this old
project of mine.

So the JH MidiMini has a very close clone of the VCF and VCA,
but it has EGs based on SSM2056 and VCOs based on SSM2033.
I think I don't have the original Minimoog Glide circuit either.

In retrospect I can say the envelopes and glide are surely not like
the Minimoogs, the VCF / VCA combination sounds very like the
original to me, and the VCOs are remarkably fat. The last one
is not my merit - I'd say I was just lucky, as the SSM2033's are
at least close to the later Minimoog VCOs in that they have a saw
(not triangle) VCO core and a heated expo converter on-chip.
OTOH 2033's are also used in the Korg Mono/Poly, and though
I like this synth for it's features, it's not exactly one of the fattest
sounding ones, despite the VCO chips. So if my MidiMini has
fat VCOs it was more or less by chance and not by design - I did
not know much about the avoiding of interlock or the power supply
noise trick back then. Speaking of PSU noise, I used the PSU board
of a dead Korg Polysix - changing two resistor values (and providing
the whole back panel of the synth for heat sinking) made the 
necessary +/-10V supply (Polysix is +/-15V).

This dead polysix (infamous battery leakage problem) has given life
to a handful of new designs.
The FX board was repackaged as a stand alone unit
(http://www.synthfool.com/diy/jh_P6_FX_detail_1.jpg),
the PSU and two of the envelope chips went into the MidiMini, and the 
keyboard, retrofitted with a clone of the Oberheim Four-Voice scanner,
is used for my JH-4 synth.
Sorry, I know this is nothing new for long time list members.
What's new is that I have added the partial circuits of the JH-4 a few days
ago; see http://home.debitel.net/user/jhaible/additional_schemos.html
for details.

JH.




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