PAiA 2720-12 Inverter/Buffer Assembly and Users Manual with Schematics

From the manual cover:

The 2720-12 Inverter/Buffer at first glance seems to be one of the simplest and least useful of all the 2720 series processing modules. Simple, as it is; its only effect is to perform a 180 degree phase inversion on any signal applied to its inputs.

Least useful, it's not; in addition to the obvious control voltage inversion applications the module also can be used for filter convolution (changing high-pass to low-pass and band-pass to band-reject) and "Q" multiplication. A 20dB input port allows the module to be used as a pre-amplifier when using the 2720 series modules as processing elements for conventional instruments with low-level outputs and tandem control voltage inputs provide for a low offset error inverting summer.

Manual contents:

The PAiA 2720-12 Inverter/Buffer manual (Instruction Manual, User Manual, Assembly Instructions) contains details for constructing a synthesizer module for a processor with functions for inversion, offset, and pre-amplification of low-level signals, from a parts kit using only basic electronics assembly tools and supplies. Included in the manual are Schematics, Illustrations and Diagrams, a Parts List (List of Parts, BOM, Bill of Materials), and set-up and use (operating) instructions.

The '-12 circuitry is comprised of an Op-amp Integrated Circuit, Resistors, and Capacitors. It requires power from an external dual-polarity 9 volt power supply. Inputs and outputs for audio signals are via 1/8" mini-phone jacks (sockets) Control Voltages are input and output via pin (tip) connectors (sockets). A panel switch offers a selection of 5v offset or not.

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