The front panel

Fig. 1

From the left: the Limit and Compress switch, Gain, the VU meter with its input and output bars, Peak Reduction, and Power.

Control	Range	What it does
Peak Reduction	0 to 100	How much levelling. Turn it up for more. Around halfway is where most vocals settle.
Gain	0 to 100	Sets the output level. The readout under the knob shows the gain in dB.
Limit / Compress	switch	Compress is gentle and smooth; Limit holds peaks more firmly.
Meter	+4 · GR · +10	Gain Reduction shows how far the level is coming down. +4 and +10 show the output level on two scales. Tap the switch under the meter to change it.
Power	switch	Turns OL-2 on or off. The lamp beside it lights while it is on.

Setting it up

1. Start with Peak Reduction. Play the loudest part and turn it up until the needle, on GR, moves a few dB on the louder phrases.
2. Make up the level with Gain. Turn Gain until the output matches the level you had with OL-2 bypassed, or switch the meter to +4 and watch the output.
3. Choose the response. Leave it on Compress for vocals and anything that should breathe. Flip to Limit for bass and for peaks that need holding down.

Let Auto Gain do step two

With Auto Gain on (on the rear panel), the output holds steady as you turn Peak Reduction up, so you can judge the levelling by ear without the level jumping.