[sdiy] Moog / Realistic MG-1 repaired!

[Metrophage]

Shortly before I left NYC, my friend Humza offered me an MG-1 to play
with. He said that his apartment was too small to keep more than one
synth. What scared me was when I opened the lid and saw the top-octave
divider chip. I thought "Oh no! The 'two VCOz' are done with a single
organ chip! This thing must sound horrid!". So I shelved it for a few
months.

My wife like to play with keys, and I began to become curious about the
circuitry, so I decided to repair the unit. First thing I noticed was a
wire going from the volume pot to the big cap nect to the headphone
preamp. Maybe for hotter signal out of the 1/4" jack? When I'd begin
playing, the sound would become very squelchy and die after about 30
seconds. Removing that wire did seem to help. The rest of the functions
intermittancy was caused by broken solder joints on every slider. So
now it works, more or less! The sync switch is broken for now.

My opinions: Not bad, kind of coarse, raw sound. The "countour",
envelope generators, and VCAs are quite weird. Sure, I have seen
pictures of Moogs before, but all I had played was a system 55. Being
able to choose modulation from lfo, cycling lfo, or contour is kind of
neat, in a normalised sort of way. I wonder if contour refers to an
envelope follower of sorts? The famous filter is indeed nice, but tame.

Where from here: I am going to try to add a few more panel controls.
Probably replace all of the yucky pots and broken switch... The VCOs
themselves appear to be out of the modulation loop. I am going to try
to get the VCOs to modulate each other, filter, etc. The ringmod is
quite subdued. I desire some overdrive through the filter. The RCA
jacks on the back are a corroded mess. I am going to remove their
riveted pcb and put 1/4" jacks for: envelope in, filtering in, output,
and maybe a CV or two.
CJ


	
		
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