MATRIXSYNTH: Rare Early Model 1968 Moog Model 950 Modular Keyboard Controller with "Hold / No Hold" Switch

Monday, March 28, 2016

Rare Early Model 1968 Moog Model 950 Modular Keyboard Controller with "Hold / No Hold" Switch


Here is an interesting bit of Moog synth history in via Mike Metz of Thesis Audio Service.

"Attached are photos inside a VERY rare Moog 950 modular system keyboard controller that we are restoring for a client.

This 950 keyboard, made in 1968 was one of the first 950 series keyboards ever made. It has a 'Hold-No Hold' switch instead of the "Glide- No Glide" switch found on later models made after 1969. The circuit has two reed relays nside, rather than the usual one. The first relay closes at key down and produces the standard Moog 'S' trigger for the modular system. The second relay closes at key down also. This relay's contacts are routed thru the 'hold' switch and sent to the sample and hold circuit where they short out the hold capacitor when the switch is set to "No Hold". This way, when you press a key, the standard CV is sent out, but when you release a key, the CV drops to zero, rather than be held by the sample and hold circuit through the release time. This sends the pitch of the oscillator from audio to basically zero when the key is released, making it appear that the note disappears, or "No Hold". Actually, the oscillator will drop to it's lowest frequency, perhaps around 1HZ, so you might hear a little 'putt-putt' noise from the oscillator, but not the correct audio output.

The later 950 keyboards changed the rocker switch function to the more common "Glide- No Glide", yet both keyboard versions kept the same 950 model number. There was no mention of this early version 950 in any of the Moog documentation that I have ever found.

The other fascinating thing about this keyboard is seen in the photo of the bottom of the circuit board. There are hand made scribe marks on the boards around the hand-laid PC traces, probably put there during inspection during assembly. We can't be certain who made these marks on the PC board, but being from 1968....???"

The serial number for this one is 1008.

These aren't common. Only three with the "Hold/No Hold" switch have been featured on the site before, one in 2007, one in 2010, and one in 2011.

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