<- Pipe Chamber Products

MIDI Pipe Control Unit (MPCU)


This is a MIDI-Input version of the PCU, intended to be used as an interface between an electronic organ console and a pipe organ.  The MIDI Pipe Control Unit (MPCU) is contained in a metal box, which has a hinged "pin-board" panel to which all connections to chest magnets are made. Two versions are available - 16 driver cards (with front panel PCIO-1) or 20 driver cards (PCIO-2).



This is a MIDI-Input version of a PCU, and includes a PCC with firmware optimized for use with input from our MCU (MIDI Control Unit), or an electronic organ console (such as Ahlborn-Galanti or Viscount).  It includes coupling functions to reduce MIDI traffic and minimize delay due to limited MIDI bandwidth.  It handles all PCC features, such as C-C# split chests, doubled outputs, swell engine outputs, etc.

Normally, all outputs for chest magnets are negative-going (active-low) so that a positive common is used on all chest magnets. If required (or preferred) outputs may be active-high (positive-going, negative common on chests) by using a different type of driver board. Drivers can even be mixed, if required.

The box is 15" wide by 21" high and about 6" deep (including connectors). The hinged panel (14" x 21") is a heavy-duty printed circuit board with rows of pins onto which cables may be plugged. Holes are provided at the hinged edge to tie cables down. There is also a "pin-board" on the left side for miscellaneous connections such as MIDI-IN/OUT, expansion cable out, etc. Heavy-duty binding posts are used for +12V input from the chamber power supply (or organ rectifier). The box is designed to be mounted on the wall of the chamber so that all connections are easily accessible. It eliminates the Pipe organ relays of older systems. The box is controlled by a MIDI source using one channel per division.



Connections on the front panel (PCIO-1) are made to 16 rows (8 ranks) of 48 output pins. To the right of each row is a terminal block to which commons should be connected. (Positive common outputs use internal self-resetting fuses.)

There is also a version with 20 rows (10 rqnks) of 48 output pins. This panel (PCIO-2) is the same size as the 16-row version. Extension boxes may be bolted to top or bottom for more ranks.



  • Handles all MIDI messages for Note On/Off, Expression, as well as SysEx messages for Viscount stops, couplers, and tremolos.
  • Contains a Pipe Control Computer internally, so almost all PCC features are available, plus coupler functions (to minimize MIDI traffic).
  • Connectors on the side panel allow for connection to remote driver boards via RS422 outputs and to provide a buffered output to another PCU (in the same or another chamber).
  • An AC Chime driver board may be installed inside. This board replaces Chime relays used in older organs. The wiring to Chime magnets can be routed through a large hole at the right side.
  • Every row is fitted with a self-resetting fuse.
  • Implements 'Unit organ relay' functionality using state-of-the-art electronics.
  • Packaged unit reduces wiring between boards.

Consists of a heavy-duty metal box with a face 'pin-board' (PCIO-1 or PCIO-2) for connection to chest magnets/pipe magnets, expression shade motors, tremulants, and pressure switches. A side panel 'pin board' is used for serial input from the Console, MIDI input from the console, miscellaneous connections for remote drivers, MIDI I/O,  Temperature sensor input, and repeater outputs to a second chamber.


Technical Specifications

  • Size: 15" (wide), 21" (high), 6" (deep)
  • Power: 12-15V (organ rectifier) at 30 Amps peak
  • Outputs are Active Hi or Low
  • 768 Outputs (16 Drivers x 48 Outputs) or:
  • 960 Outputs (20 Drivers x 48 outputs).



An OrganWorks file is used to fully describe an organ, including stop names, and chamber information. An OrganWorks file from a previous job may be used as a template. When we receive the OrganWorks file, we can quickly configure the chamber (PCC) program, and deliver a Pipe Control Unit (MPCU) containing driver boards required to drive the pipe-chests in the organ.

A collection of OrganWorks files is available to show various standard models. These have stops, couplers, pistons, toe studs, etc., already entered and may be used as templates to describe the actual organ. You need only to add stop names, chamber information and link the stops to ranks of pipes.



PCU Photo: View Download

Packaged Systems Brochure: View | Download



Go to top
Template by JoomlaShine