MATRIXSYNTH

via this auction

"Hand made 6 oscillator mini synthesizer

I have been making synthesizers for over 10 years but this is the first time I have made anything to sell. To see all my work go to nicksworldofsynthesizers.com

The 6 knobs tune the oscillators and the keys switch them on. In normal mode it can make simple melodies and harmonies.

There is a switch that makes all the oscillators sync to the first oscillator. This has the effect of making the oscillators lock to the nearest harmonics of the first oscillator and makes some very strange harmonies.

The chaos depth knob makes all the oscillators attempt to sync to each other. The result is quite extreme unpredictable noise and sonic convolsions.

The circuit is descrete transistor which give the sound a rich analogue quality. The case has a nice vintage industrial design with engraved lettering and phenolic moog style knobs."

Update via Billy in the comments:

"Dude used to be in Pink Grease... played one of the most insane looking diy synths ever..."

Pink Grease on MySpace

Also see this video.

Update via Jimmersound in the comments: "More here [Nick's World of Synthesizers]" Originally posted back in 2007 when it lived on a different site. And we come full circle. I thought I recognized it.

Rare Moog

YouTube via bobbybot2000 — May 22, 2010 — Moog Cordovox white elephant organ

Hillwood Ultra Rare Keyboard Called The Blue Comet 73

YouTube via bobbybot2000 — May 22, 2010 — via this auction

Univox Multi Man Keyboard

YouTube via bobbybot2000 — May 22, 2010 — via this auction

Rare Oberheim DS-2 Digital Sequencer

via this auction

Vintage Arp Axxe Analog Synthesizer

YouTube via bobbybot2000 — May 22, 2010 — via this auction

via this auction

S-CAT (0439) CIRCUIT BENT CASIO VL-1 (10 MOD) MONSTER

via this auction
"T E N V E R Y N A S T Y M O D I F I C A T I O N S LCD SCREEN HAS BEEN REMOVED F O R A N I N D U S T R I A L L O O K AND LED HAS BEEN FITTED IN THE SCREEN - PLEASE NOTE THIS COMES ON WHEN A PSU IS INSERTED WHETHER THE MACHINE IS SWITCHED ON OR NOT
1. RHYTHM FILTER CUTOFF
2-3. SWITCHABLE ROTARY RHYTHM SQUANKER USE THE CENTRE TOGGLE SWITCH FOR HIGH OR LOW FEEDBACK

4. VOICE FILTER I CUT OFF
5. NOTE HOLD WILL REPEAT WHEN HOLDING DOWN A NOTE ON THE KEYBOARD WHILE A RHYTHM IS PLAYING
6. VOICE FILTER II TONE/ATTACK
7. VOICE DRIVE DISTORTED OVERDRIVE
8-9. RHYTHM/VOICE DRIVE I / II ADD A TOUCH OF BOOST OR BANG IT UP!
10. EXTREME PITCH MODULATOR TAKE IT DOWN LOW FOR SUPERB BASS

+ BONUS FEATURE USE THE MAIN VOLUME SLIDER IN CONJUCTION WITH THE RHYTHM SQUANKER TO CREATE MORE VARIATION TO THE MODIFIED SOUND"

videos previously posted
S-CAT on Ebay

circuit bent kawai k1m vector synth by spunkytoofers

via this auction

details and video captured in this previous post and this video.

Crumer Trilogy Analogue Synth

via this auction

"The name Trilogy of course (in the same vein were, for example, the Korg Trident, the ARP Omni 1/2, and the Moog Opus 3) comes from the fact that this instrument features three sections: Organ, Strings, and Synthesizer."