METASONIX TM-1

via this auction
"World's first vacuum-tube audio ring modulator for music production, plus all-tube waveshaping. Very complex distortion effects. 100% compatible with other analog synths. Unit usable standalone or may be mounted in a 5U-high modular synthesizer system.

Controls
* Input Level
* Pulser Stability
* Beam Tube Screen
* Ringmod Osc Pitch
* Activate Ringmod

Sockets
* Audio Input
* Audio Output
* Beam CV
* VCA CV
* Ringmod Carrier
* Frequency response: less than 10 Hz to greater than 40 kHz
* Distortion: from less than 0.1% to 100%, depending on control settings and input waveform
* Hum and noise: less than 0.5 mV
* Power input: 10 - 12 volts AC, 50/60 Hz, 0.8 amp at idle
* Inputs: phone jacks for audio input; optional inputs for beam-tube CV, VCA CV, and ring-modulator external carrier (requires at least 20v p-p signal for full effect) Output: audio (mono)
* Dimensions: 7 1/2" (192mm) x 4 3/8" (112mm) x 3" (77mm)
* Weight (not including accessories): 5 pounds (2.2 kg)

'The Metasonix TM-1's circuit is directly derived from the award-winning Metasonix TS-21 "Hellfire Modulator".

The pentode preamp gives pure tube distortion, from soft and creamy to screaming guitar-amp like leads. Just crank the input volume.

The "pulser" circuit injects small, badly-formed pulses on top of the signal, giving an effect roughly similar to very erratic (and violently unstable) VCO sync. Forget getting this effect from another synth, analog or digital; they just can't do it. It sounds out of control, yet it is easily tweaked over a broad range with the PULSER STABILITY knob. Subtle, or gross; a vast range of sonic manglings are at your fingertips. (The pulser circuit works best with sharp-edged electronic waveforms, especially those from digital synths or analog VCOs.)

Finally, a special beam-deflection vacuum tube gives both wavefolding and ring modulation (carrier is provided by an internal wide-range oscillator, or inject your own carrier signal). There is nothing quite like the crossmodulation produced by the beam tube, its nonlinearities and resulting tonal effects are distinctive. Crude and NASTY, too.

TM-1's pulser effect uses a positive feedback loop, so the circuit is not stable under all settings. This allows its use as a self-contained pseudorandom signal generator, by patching its output back to its input. You've read about "strange attractors" and other chaotic sound generation techniques? The TM-1 is the first all-tube chaotic sound generator. The results must be heard to be believed!'"