Using The Opto-Compressor - Avalon VT-737SP Operation Manual

Creating Distortion or Overdrive
You can achieve interesting distortion sounds
ranging from loose tube overdrive to tight
discrete distortion. Be very careful experi-
menting with this because the Vt-737sp can
get very loud and can cause serious damage
to your speakers or ears. Avalon recommends
that you first experiment using a line level input
such as a guitar or bass plugged into the front
panel instrument jack (not a microphone). If you
want to try this with a microphone, be careful
not to create a feedback loop.
To create tube overdrive:
1. Turn the INPUT selector swtich to the
desired input source and plug in your input
source to the corresponding input.
2. Set all knobs to unity and disengage all push
button switches.
3. Turn OUTPUT control fully counter clock-
wise.
4. Make sure you turn OUTPUT control fully
counter clockwise.
5. Turn PREAMP GAIN control fully counter
clockwise (minimum).
6. Press in the HIGH GAIN switch.
7. Slowly turn the PREAMP GAIN control fully
clockwise while feeding input signal.
8. Slowly turn the OUTPUT control clockwise
until the output level is comfortable for you and
your recording device.
8. Turn down the PREAMP gain control for less
distortion.
To create tighter distortion by also overdriving
the Equalizer section:
1. Follow steps 1-4 in previous example and
continue.
2. Make sure the OUTPUT control is fully
counter clockwise (minimum).
3. Press in EQ switch to engage the EQ.
4. Set BASS shelving frequency to 150 Hz.
5. Set the LOW MID frequency to 400 Hz.
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6. Set the HI MID frequency to 2KHz.
7. Set the TREBLE frequency to 10KHz.
8. Turn all four EQ gain controls fully clockwise
(maximum).
9. Slowly turn the PREAMP GAIN control fully
clockwise while sending signal.
10. Slowly, slowly, slowly, turn the OUTPUT
control clockwise until you get desired level.
11. Experiment with the EQ settings to get a
desired tone.

4.4.2 Using the Opto-compressor

The opto-compressor of the Vt-737sp has all of
the standard features of an outboard compres-
sor plus de-ess, side-chain and pre/post EQ
switching. Basic operation is as follows:
1. Engage the COMPRESSOR push-button.
This will insert the compressor into the signal
chain.
2. Engage METER push-button. The VU meter
is now set to display gain reduction.
3. Set ATTACK to FAST.
4. Set RELEASE to FAST.
5. Set COMPRESSION to 20:1 (Fully Clockwise)
6. Set THRESHOLD to -30dB (Fully Counter
Clockwise)
7. Test compression by introducing signal.
Needle should move pretty rapidly for any input
signal. Turn up the PREAMP gain if needle is not
moving.
Avalon Vt-737sp Operation Manual
Operation and
Controls