Buchla Model Model 281e AND Model 292e

via this auction
http://buchla.com/
"The Model 281e Quad Function Generator has four function generators organized in 2 pairs. All four normally function independently. A momentary switch selects one of three modes: transient, sustained, and cyclic. An illuminated LED indicates the selected mode. On receipt of a pulse, the output voltage ramps up to 10 volts at a rate determined by the sum of an applied control voltage and the setting of the attack time knob. If in the sustained mode, the voltage will stay high as long as the input pulse is maintained. If not in the sustained mode, or when the input pulse terminates, the output ramps down to zero at a rate determined by the sum of the decay voltage and the setting of the decay knob. At the end of the decay, a transient pulse appears at the pulse output. If in the cyclic mode, the cycle now repeats. The time range for both attack and decay is from .001 to 10 seconds. In the quadrature mode, generators A and B (or C and D) operate in tandem to provide functions shifted by ninety degrees. The mode is selected with a switch and indicated with LEDs. An OR function can be invoked to generate more complex envelopes (ADSR). The model 225e or the 206e preset manager can issue commands to store and recall the 281e's settings. The 281e can respond directly to MIDI signals received by the model 225e MIDI interface.

The Model 292e Quad Dynamics Manager is functionally identical to the original 292, with the exception of two new features - the 292e has velocity inputs, allowing controllers to control note volumes with performance gestures. And its settings can be stored as a part of a 200e series preset. The 292e sports four independent voltage controlled amplifiers. Each has a signal input and output, a control voltage input that varies the unit's gain from -120 to +3db, an offset adjustment, and a velocity input. The latter adds further control to the gain when employed and becomes transparent when unconnected. A switch selects one of three operating modes: straight gate (VCA), lowpass filter (VCF), or a combination of the two, in which the spectral response varies as the gain is changed. Frequency domain gating imparts a dynamic tonal variation that gives the listener a sense of absolute loudness. This quality is characteristic of all acoustic instruments (the harder you strike, pluck, or blow, the richer the overtone structure). A mix of the four output signals is also provided. Aided by the model 225e or the 206e preset manager, the settings of the 292e can be stored and retrieved."