Buchla and Tiptop Audio 296t Eurorack Spectral Processor Module

The Tiptop Audio Buchla 296t module is designed to replicate the complexity of Don Buchla’s Programmable Spectral Processor Model 296, which encompasses filtering, envelope following, vocoding, and more. It incorporates 16 fixed-frequency filters; these filters all use the same inputs, but understanding the other features requires closer examination of the output sections.

There are three audio output sections: Comb Filter Outputs, Attenuator Outputs, and Programmed Outputs. The Comb Filter Outputs provide the sum of the odd and even filter bands. The Attenuator Outputs respect the front-panel level control sliders, delivering summed outputs of all the bands and the odd/even bands as groups. The Programmed Outputs (even, odd, and all) are controlled by the Program Control, Programmed Spectrum Transfer, and Local Program CV controls.

In essence, the Program Control’s frequency and width controls enable you to “scan” the filterbank and focus on specific frequency ranges at the Programmed Outputs with the option of voltage control. The Local Program Inputs are voltage control inputs that allow for more granular control of the level of each individual band at the Programmed Outputs. The Programmed Spectrum Transfer section allows you to connect the envelope follower outputs from the odd bands to the even bands’ CV inputs or vice versa. When thoughtfully used in tandem with the Even and Odd audio inputs and outputs, this enables crude but effective vocoder-like behavior.

Furthermore, direct envelope follower outputs and audio outputs are available for each band. The Eurorack format’s compact design necessitates several compromises in terms of user interface vs. the original Buchla module, but overall, the 296t fits most of the features of the original Buchla module into a format that is more accessible to many musicians. It will be a welcome addition to any 200t system.

Features

• Complex filter bank based on original Buchla 296 design
• Sixteen fixed filters with an array of audio and CV inputs and outputs
• Inputs for odd, even, and all bands
• Comb filter outputs provide sum of odd and even bands
• Attenuator outputs provide odd, even, and all filter summed outputs with levels controlled by front-panel sliders
• Programmed outputs respond to control voltage and programmed spectrum control/spectrum transfer functions
• Direct audio outputs for each filter band
• Direct envelope follower outputs for each band (with global response time selection)
• Capable of filtering, vocoding, and much more

Specifications
Width: 52hp
Depth: 52mm
Power: +360mA, -350mA

Manufacturer product page here.
Product manual here.