TipTop Audio Buchla Model 285t

• Up to 1kHz of frequency shifting available via the internal oscillator
• Bipolar CV and linear FM inputs for the refence oscillator
• Sum and difference outputs allow for both upwards and downwards frequency shifting

TipTop Audio Buchla Model 285t

Frequency Shifter

The 285t combines two sets of functions: the top section features a frequency shifter, while the lower section includes both balanced modulation and classic ring modulation, all with voltage control. The frequency shifter can shift incoming audio using either its internal oscillator or external audio. Both SUM and Difference outputs are available simultaneously for analog stereo widening effects and more.

The 285t Frequency Shifter is an interesting module for processing audio samples or live voice input via a microphone through the 207t Mixer/Preamplifier module.

The "sum" and "difference" outputs from the 285t can then be routed to the 292t Quad Lopass Gate, creating dynamic tone shaping. By further splitting the processed signals into the left and right channels, this setup allows for a rich stereophonic effect.

The “ring” double output is a pure ring modulation determined by the incoming signal and ref.

The bottom MODULATION section applies to the “variable” double output.

The CV input and its attenuverter modulates the sweep from “zero-amplitude-ring.”

The Balanced Modulator receives an audio signal at the “signal” input. This can be thought of as the carrier while the “ref.” input receives a different audio signal (the modulator).

The "amplitude" knob manually sweeps from zero (the pure incoming “signal”) through amplitude modulation ending in pure ring modulation. When this knob is set fully CW to “ring” it is the same signal as the “ring” outputs.