This is a very cool but tweeky piece of gear. The L.E.D. meter is very funky and non intuitive but very easy to "read" once you understand it, but that's a different page!

Starting position:
Turn unit on for a15 min warm-up.
Phantom - OFF
Input - +4dBv
Trim - "12 o'clock"
Threashold - Full Clockwise
Gain Reduction - Bypass
Compressor - All @ "12 o'clock"
Output - "2 o'clock"

Set up for unity gain.
1) Put the "METER SELECT" into the "Input" Position.
2) Connect a 1KHz, line level, sine osc to the line input.
3)Adjust the Input switch and trim so that the "0" meter LED meter is BRIGHT.
4)Switch the "METER SELECT" to the OUTPUTposition.
5)Adjust the OUTPUT TRIM until the "0" meter LED meter is BRIGHT.

Calibrate the gain reduction circuit
1) Preform steps 1-5 listed above
2) Release the "BYPASS" and adjust the little tiny screwdriver trim pot, at the RIGHT side of the analog (iron vain) meter, until the "0" meter LED meter is BRIGHT.
3)Rotate the "THREASHOLD" knob CCW until the pointer points to the "0" LED.
4) NOTE: DO NOT remove the top to make this adjustment as the
temperature inside the unit will change and you'll be screwed.
There is a little trim pot which is accessable through the holes in the unit top. It's about half way back , on the left edge of the right side holes. Use a flash light to help you find it. Anyway. Adjust the trim pot until the "-3" LED is Bright.
Your finished.