Projects

SSL Mix Buss Compressor Clone Control


Progress: 1%

This project is about adding some extra electronics into my SSL Mix Buss Compressor clone to allow digital control for automation and total recall right from Pro Tools. It's still in progress (mostly in my head), but I'm hoping to document here it as I design it. See here for the details of the original SSL Clone project.

Requirements

  • I already have an SSL Mix Buss Compressor clone, so it should be a modification to the standard way people build these things.
  • I've alredy cut out my front panel, so I should do as little as possible to that.
  • It should support all of the standard mods to the SSL, so that it's useful for everyone. (Sidechains, Turbo, Relay Bypass etc).
  • When there is a computer connection, you should be able to change settings on the hardware as well as in the software.
  • It should be able to work without a computer connection as well as with.
  • It shouldn't require drivers for the computer connected.
  • It should work with Mac OS X and Windows.
  • It should work with most DAW software.

This lists of requirements leads to:

Solution

  • Replace the SSL front panel PCB with a new PCB with a computer interface.
  • Write a VST plugin that has a virtual version of the hardware.
  • Use MIDI for the messaging between hardware and PC.
  • The new hardware will have a USB interface that uses class compliant MIDI drivers, so no extra drivers are needed.
  • The hardware will have standard 5 pin DIN MIDI interfaces (In, Out and Thru) so that other devices can control / be controlled.
  • Replace all of the lorlin switches and pots with rotary encoders (easy to retrofit into the already drilled front panel).
  • LED indicators on each rotary encoder (to show the current status).
  • Replace the lorlins with some digitally controlled switching matrix.
  • Use some D to A to replace the threshold and make up gain pots.

I've chosen to implement this with the following:

Implementation Details

  • 6 rotary encoders (1 each for Threshold, Ratio, Attack, Release, Makeup Gain, Sidechain).
  • 2 buttons (1 for Bypass, 1 for Turbo).
  • AVR AT90USB1287 Microcontroller.
  • Analog ADG High Performance Analog Multiplexers for the analog switching.
  • A to D to get meter position.

More details as it happens.


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