Pan / Fade

When I was working on the development of the Active Processor module/PCB’s, the original schematic made it quite obvious you could use the PCB in many ways. I wanted to make the most of the board and made it able to either VC Crossfade or VC Pan.
When the mode switch is in the Pan position, Input 1 is active (input 2 will be ignored) and the VC Pan input will send the input to either of the two outputs. When the mode switch is in the Fade Position, Inputs one and two are active, but only output 1 will be functional, allowing the module to cross fade under voltage control.

From the original SMMS Catalog:

“The ACTIVE PROCESSOR (ACPR) is an accurate, linear cross-fader for either control voltages or audio signals. This module provides an important link in complex patches, allowing the user to smoothly change from one control voltage to another. It is possible to cross-fade between different envelopes, for example, or to gradually switch control over a bank of oscillators from one output of a sequencer to another output. A scaling buffer is included in the bottom section to further invert and process control voltages.”



** 4U Modular is a term used for the format most commonly known as “Serge Format” or “Loudest Warning Format”. Out of respect for the ever growing format, 4U Modular is the easiest way to refer to it. More Specifically it refers to the panel height and mounting hole style. 4U Modular will patch up just fine with other 4U "Serge" formats such as "Random Source", but it will not mount in RS boats or Buchla Boats (or power off Buchla power for that matter). An info page about this will be added to the website soon to make this a lot more easy to understand.

DIY Information:
LGE201P Main PCB Bill of Materials
LGE201P Main PCB Schematic
LGE201P Main PCB Designators
LGE201PC I/O PCB Bill of Materials
LGE201PC I/O PCB Schematic
LGE201PC I/O PCB Designators

Calibration: Read Me
Mechanical Parts BOM generally required for building Low-Gain Electronics Modules

One thing to understand about this type of circuit… like the Universal Audio processor, ACP or other similar circuits: If your Pan/Fade Bias control is in the full clockwise position, and you are
feeding CV In, you will get more gain from the 2nd VCA than unity because of the nature of summing both the Bias CV as well as the external CV. It’s just the nature of the circuit. If you’re building the module. you could consider
a 5V1 Zener Diode from Pin 6 of U2 to ground. I haven’t tested this, but it may help. It’s how the original circuit works, and I wanted to make sure the users aren’t scratching their head thinking it’s not working correctly. This
is also the same issue on the Stereo Mixer. It has a reputation of having a very hot output.

Details:

• PCB Size: 6” x 1”

• Current Draw: TBD