Buchla Modules Now Available In Affordable Eurorack Format

At Superbooth 2021, Tiptop Audio and Buchla USA announced a joint project to make classic Buchla 200 Series modules available as affordable Eurorack modules.

Now the first two of these modules are available to pre-order: the Buchla 281t Quad Function Generator & Buchla 258t Dual Oscillator.

Here’s the official intro video from Superbooth:

Tiptop Audio Buchla 281t

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

Each function generator can act independently as well as in pairs via Quadrature mode—triggering and balancing two generator outputs with each function shifted 90 degrees out of phase, for creating complex modulation sources ideal for quadrophonic movement.

Determine the rate at which the function rises and falls with the Attack and Decay parameters, respectively, each with voltage control over times spanning one millisecond all the way to ten seconds. Each function can be triggered via a manual trig button or via their trig inputs, with three different modes of operation per function generator. Cyclic mode will cycle the function continuously for LFO-like behavior, while Transient and Sustained modes act as conventional Attack/Decay and Attack/Sustain/Release envelope generators, respectively. Introducing a gate atthe cycle input will activate cycling in any mode, allowing you to inject moments of looped modulation.

Each generator has a dedicated output for shaping your audio and modulation signals, and additionally, each generator’s end of decay will also send out a trigger pulse—great for introducing triggered or clocked signals to other modules or even self-patched modulation.


  • ‘Faithful revival’ of the Buchla Quad Function Generator Model 281 in Eurorack format
  • Formatted for Eurorack height in a longer module, with minimal adjustment to functionality
  • Four identical function generators to produce envelopes and LFOs
  • Entire unit sends and receives Eurorack level signals via standard 3.5mm jacks
  • Attack and decay times both range from 1ms to 10 sec, each with CV input (longer times available via external CV)
  • Trigger button and input activate the function generator
  • Mode switch determines how function generator acts to triggers and gates (Cyclic, Transient, and Sustained)
  • Cycle CV input enables and gates cycling
  • Per channel function generator output and end of decay trigger output
  • Quadrature mode to enable paired generators with functions shifted by 90 degrees of each other
  • Adjustable analog OR functionality for creating complex envelope shapes

Tiptop Audio Buchla 258t

The Dual Oscillator Model 258t is a Eurorack-format recreation of the original dual VCO. The 258t is a nearly-identical replica, resized to 3U size, with rescaled voltage ranges and standard 3.5mm jacks.

Meant to interface with other Tiptop Buchla modules and Eurorack systems as a whole, the 258t features inputs for modulating the pitch and waveshape of each oscillator. Looking at them more closely, the notable difference between the two oscillators is the waveshape control, providing a sine-to-saw shape on oscillator one and a sine-to-square shape on oscillator two. The processing inputs paired with an attenuverter allow for positive or negative pitch scaling, inversion, and even expansion to the broad 5Hz–20kHz frequency range.


  • ‘Authentic recreation’ of the Buchla Dual Oscillator 258 in Eurorack format
  • 200 Series module with minimal changes
  • Each oscillator contains mirrored jacks and controls with only one difference between them: the waveshape control
  • OSC 1’s waveshape moves from sine to saw, while OSC 2’s waveshape moves from sine to square
  • Tini-jax and bananas have been replaced with 3.5mm Eurorack standard jacks
  • Waveshape controls feature an input for modulation
  • Processing attenuverter for extra scaling, inverting, and expansion of pitch
  • Coarse and fine tune controls sweep the oscillator frequencies range from 5Hz to 20kHz with original “cps” and “kc” description
  • 1V/Oct tracked pitch input

Pricing and Availability

The Buchla 281t is available to pre-order at Perfect Circuit and other retailers for $210, while the 258t Dual Oscillator is available to pre-order for $199. See the Tiptop Audio site for more information.

via Synth Anatomy