via this auction
"This is the fifth MOTM-300 VCO I have and the last one I purchased used a couple years ago. I'm trying hard to force myself to stop the endless expansion of my modular synth and need to let go certain modules that don't fit into my existing cases.
I re-calibrated the tracking last month and it was very solid over 6 octaves. Due to differences in power supplies you may need to re-calibrate it once you get it into your system. This is not a stand alone device and requires a MOTM style cabinet and power supply to be able to use it. If you want to learn more check out the "5U" section of the excellent "Muff's Modules & More" forum.
It's in very good shape and works well. There are a couple minor odd looking things the original builder did but they don't affect performance, and I forgot about them until I took pictures of the module:
1) a lock washer for one of the toggle switches is on the outside of the panel instead of the inside
2) the wiring to the jacks, pots and switches isn't as neat and trim as I or a professional builder might have done
The MOTM-300 is a fantastic VCO and that's what you'll hear when you listen to most of my over 200 YouTube videos. In this video [posted here] for example you can hear the beautiful raw unfiltered sound of four MOTM-300 VCO's, and in this video [posted here] hear the power of three MOTM-300 VCO's filtered through a Moog 9504 low pass filter.
Edited description from the designer's site: http://www.synthtech.com/motm300.html
The MOTM-300 Ultra VCO represents a milestone in analog synthesizer design. Using only the finest available circuitry, the Ultra VCO has unmatched performance where it's needed most: stability and tracking. Although we put the focus of the design on stability, the MOTM-300 is indeed a 'full-featured' VCO. Sine, Saw, Triangle, and Pulse waveforms are all available simultaneously. PWM (Pulse Width Modulation) with initial pulse width and depth creates complex spectra.
