⁙ Input impedance 1 MegOhm
⁙ Output impedance 1 kOhm
⁙ Power supply 9V DC, center-negative plug (standard size)
⁙ Internal charge pump doubles the voltage for higher headroom
⁙ Current draw 50 mA max (The older OTA model runs at lower current, 16 mA)
⁙ Size 62 mm x 112 mm x 50 mm
⁙ Weight 400 g
⁙ The footswitch is a relay-based true bypass.
⁙ The pink LED indicates when the compressor is switched on.
⁙ The orange LED indicates when your signal is being compressed.
⁙ When you first plug in, it is normal for the orange LED to come on and stay on for a couple of seconds.
⁙ The Thresh switch engages a -20 dB pad on the input of the compressor sensor, to reduce overloading from very high-output instruments. It does not reduce the audible volume of your signal.
⁙ The Sust knob controls a gain stage going in to the compression circuit, so it affects both threshold and ratio together. Higher knob settings mean a lower threshold and a higher ratio.
⁙ The Attack knob actually controls both attack and release times. Turning the knob clockwise gets a slower attack and a faster release. Counterclockwise settings will be smoother, more fluid, while clockwise settings will be more percussive.
⁙ Range of attack times: approximately 1 mS to 100 mS
⁙ Range of release times: approx 100 mS to one second (These time ranges are for the old Smoothie; correct ranges for new Opto Smoothies will be posted soon.)
⁙ The Comp Vol knob controls the volume of the compressed signal.
⁙ The Direct knob controls the volume of the dry/uncompressed signal.
⁙ The Tone (EQ) section only affects the compressed signal, not the dry signal. It is a "tilting" EQ, so when turned left of center it cuts highs and boosts lows, turned right of center it cuts lows and boosts highs. The tilting point is around 350 Hz.
⁙ Try this setting as a start:
Attack 12:00, Sust 10:00, Tone 11:00, Comp Vol 12:00, Thresh 0dB, Direct 9:00


Here is a graph of the frequency response, with the tone knob set at noon, using a white noise source.
The green line is bypass, and the blue line is with compression at maximum:

Frequency Response Graph

This graph shows the range of effect of the Tone knob:

Frequency Response Graph