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Tiptop Audio and Buchla USA announced a cooperative effort at Superbooth 2021 to make vintage Buchla 200 Series modules inexpensive Eurorack modules.

The Buchla 281t Quad Function Generator and Buchla 258t Dual Oscillator, the first two of these modules, are now available for pre-order.

Here’s Superbooth’s official entrance video:

Buchla 281t Tiptop Audio

The Model 281t Quad Function Generator is a Euro-format reproduction of the original 200 Series module. By replacing the banana jacks with 3.5mm TS jacks, the 281t recreates a classic envelope/LFO and implements complete Eurorack CV I/O.

Each function generator may operate separately as well as in pairs through Quadrature mode, which involves triggering and balancing two generator outputs with each function shifted 90 degrees out of phase to provide complex modulation sources suitable for quadrophonic movement.

Determine the pace at which the function rises and falls using the Attack and Decay parameters, each having voltage control across periods ranging from one millisecond to 10 seconds. Each function can be initiated by a human trig button or by their trig inputs, and each function generator has three modes of operation. Cyclic mode will continually cycle the function for LFO-like behavior, but Transient and Sustained modes will provide traditional Attack/Decay and Attack/Sustain/Release envelopes, respectively. Adding a gate to the cycle input activates cycling in any mode, enabling you to inject looping modulation.


  • The Buchla Quad Function Generator Model 281 has been faithfully revived in Eurorack format.
  • Formatted for Eurorack height in a larger module, with few functional changes.
  • Four identical function generators are used to generate envelopes and LFOs.
  • The entire machine transmits and receives Eurorack level signals using normal 3.5mm connectors.
  • Attack and decay periods with CV input range from 1ms to 10 sec (longer times available via external CV)
  • The function generator is activated by the trigger button and input.
  • The mode switch controls how the function generator reacts to triggers and gates (Cyclic, Transient, and Sustained)
  • Cycling is enabled and gated via the Cycle CV input.
  • The output of the per-channel function generator and the end-of-decay trigger
  • Quadrature mode enables the use of paired generators with functions that are 90 degrees apart.

Buchla 258t Tiptop Audio

The Dual Oscillator Model 258t is a Eurorack-format clone of the original dual VCO. The 258t is a virtually identical duplicate that has been shrunk to 3U, including rescaled voltage ranges and standard 3.5mm plugs.

The 258t is designed to interact with other Tiptop Buchla modules and Eurorack systems in general, and it has inputs for altering the pitch and waveshape of each oscillator. The waveshape control, which provides a sine-to-saw shape on oscillator one and a sine-to-square form on oscillator two, is the most noticeable variation between the two oscillators. Positive or negative pitch scaling, inversion, and even frequency expansion to the vast 5Hz–20kHz frequency range are all possible when the processing inputs are combined with an attenuverter.


  • Buchla Dual Oscillator 258 ‘authentic replica’ in Eurorack format
  • Minimal adjustments to a 200 Series module
  • Each oscillator has mirrored jacks and controls except one: the waveshape control.
  • The waveshape of OSC 1 changes from sine to saw, whereas the waveshape of OSC 2 changes from sine to square.
  • Tini-jax and bananas have been replaced with normal 3.5mm Eurorack jacks.
  • Waveshape controls include a modulation input.
  • Processing attenuverter for more pitch scaling, inversion, and expansion
  • The coarse and fine-tuning knobs sweep the oscillator frequencies from 5Hz to 20kHz using the original “cps” and “kc” descriptions.
  • Tracked pitch input of 1V/Oct

The Buchla 281t is available for pre-order at Perfect Circuit and other retailers for $210, while the 258t Dual Oscillator is available for pre-order at Perfect Circuit and other retailers for $199. For additional information, visit the Tiptop Audio website.


Links of interest

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Author Isaac Elejalde

Born in Maracaibo and based in Berlin, Isaac Elejalde established himself as one of the most prolific producers on the Venezuelan scene today.

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