MOOG Sonic Six 6 Analog Synthesizer

via this auction

"This is a vintage Moog Sonic Six, a little-known and even less understood two-note synth from the mid '70s. Every once in a while, one of these pops up on Ebay with very little description of what it really does. I think it’s time to change that. The first thing most people want to know is how it stacks up against the iconic Minimoog. Here is my own (maybe somewhat biased) comparison.

What you get: Think “Minimoog”, then add another LFO, add a ring modulator, add a 4-octave keyboard, add two-note capability, add more modulation routing capabilities, add a built-in carrying case, and add a practice amp and speaker.

What you don’t get: You don’t get a separate envelope for the filter, since there is only one used for both VCA and Filter. You don’t get a mod wheel, so you have to use the knobs on the panel. You don't get any wood.

VCOs
Sonic Six - 2
Minimoog – 2 (sometimes 3, see LFOs next)

LFOs
Sonic Six – 2 (called Gen X and Gen Y)
Minimoog – 1, or 0 if you use this third oscillator as an additional audio oscillator

Filter
Sonic Six – 1: Resonant Lowpass
Minimoog – 1: Resonant Lowpass

Envelope Generators
Sonic Six – 1, Attack and Decay, with a Mode switch to sustain notes as long as the key is held.down.
Minimoog – 2 , Attack, Decay and Sustain. Separate envelopes for Amp and Filter.

Noise Source
Sonic Six – Yes, Pink or White noise
Minimoog – Yes, Pink or White noise

Ring Modulator
Sonic Six – Yes, use Osc A or GenX/GenY to modulate Osc B or External Input.
Minimoog – No

Pitch Bend Wheel
Sonic Six – Yes
Minimoog – Yes

Modulation wheel
Sonic Six – No, you must use the front panel dials
Minimoog – Yes

Portamento (Glissando or Glide)
Sonic Six – Yes, high note priority
Minimoog – Yes, low note priority

Keyboard
Sonic Six – 49 Keys, Duo, Low note priority for Osc A, High for Osc B, or high note for both Osc in Mono mode. Continuously variable microtonal scaling.
Minimoog – 44 Keys, Mono, Low note priority.

A440 Tone
Sonic Six – Sort of. Turn Osc B tuning knob all the way to the left until it clicks. This puts it in “Concert” tuning, which is supposed to be correct so you can tune Osc A to it.
Minimoog – Yes, dedicated switch

External Audio Input
Sonic Six – Yes, to Ring Modulator, Amp and Filter
Minimoog – Yes, to Amp and Filter

CV/Gate Inputs
Sonic Six – 4: Pitch CV, Volume CV, Filter Resonance CV, 6-pin Moog accessory jack.
Minimoog – 1: 6-pin Moog accessory jack.

Footswitch Inputs
Sonic Six – None
Minimoog – 2: Portamento on/off, Decay on/off.

Carrying Case
Sonic Six – Yes, built in. It’s gray plastic and looks like something a kid would carry a trombone to school in, but it also makes it “Fold and Go”.
Minimoog – No. A case will cost you about $100. Of course, the wood sides are classic and classy.

Speaker
Sonic Six – Yes. It sounds horrible, but at least you don’t need a practice amp. 5cm x 10cm.
Minimoog – No

Belongs in a Museum
Sonic Six – No way. Take it on the road, baby it in the studio, whatever. Just play it.
Minimoog – Ditto

Favorite Sonic Six Tricks
1. Set Gen X to slow ramp up, Gen Y to faster ramp down. Mix the two to get a stair-case wave and generate arpeggiator-like note runs.
2. Set X/Y balance all the way to the left until it clicks. Set Gen X to a very slow triangle wave. Set Osc A to a triangle wave one octave below Osc B. Modulate Osc A with Gen X (just a touch), and modulate Osc B with Osc A (just a touch). Now you have a simple two-operator FM synth.
3. Turn off A/B and turn up the Noise. Set Gen X and Y to square waves and experiment with envelope and filter settings to get rhythmic percussion patterns. Add resonance to taste.

This unit has several different serial numbers on various parts. The exterior case is #1863, I think I saw a #357 on the lower tray, and the upper unit (control panel and two main circuit boards) is #1395. The VCF/VCA board is Rev E, which definitely has the Moog patented transistor-ladder filter, not the older Musonics diode-ladder type."