RSPE Audio Solutions, Los Angeles Premier Pro Audio Dealer

A FET compressor reminiscent of the MC77. Designed to work in standard 500 racks.
The Action features a constant impedance 600 ohm input attenuator feeding the input transformer, just like our MC77 units. This makes the input more resistant to overload by hot signals. After the input transformer, the signal is attenuated by the same gain reduction FET as in the MC77. The attenuated signal is buffered by our class A KDJ3 opamp, which feeds the output fader. Lastly, our class AB KDJ4 output opamp drives our custom hexafilar nickel and steel output transformer. The total gain (with no attenuation) is 45dB, just like the MC77.
The attack and release times cover a broader range than the MC77, which can cause distortion... which may or may not be what you are looking for. Use at extremes with caution. The ratios are the same as the MC77, and the threshhold moves up as the ratio goes up, just like the MC77.
In the center of the unit is an SMT sidechain and stereo link amplifier, below that is our SMT compression LED ladder meter driver. Behind that is the SMT input and output tricolor LED meter driver.
Stereo linking is accomplished by cross connecting pins 3 & 6 on the edge connector. On the Purple Sweet Ten, there is a second output XLR that can be used to link two Actions. The link is accomplished using a XLR-F to XLR-F cable with pin 2 on one XLR-F connecting to pin 3 on the other XLR-F and vice versa. Plug in the cable, flip the front panel switch and you are linked. Non-Purple racks do not have an easy way to connect pins 3 and 6, and will need modification to link two Action units.

Features:

Input attenuator feeding input transformer
Output level control
Input and output tricolor LED metering
Eight LED GR metering
Five ratios including All buttons in mode
Attack and Release controls
True Relay Bypass
Stereo Linking
Compression on/off switch
Discrete signal path
Over Current Resettable Fused (prevents any module problem from affecting   your rack)
ROHS - Lead Free

For easy serviceability and tweaking, the Purple discrete opamps can be replaced with any standard discrete opamp or a DIP-8 IC.

Specs:

Total Gain: 45dBu
Ratios: 4:1, 8:1, 12:1, 20:1, :1 (All buttons in)
Attack time: Continuously Variable from over 800 microseconds to 20 microseconds
Release time: Continuously Variable from over 1.1 seconds to 50 milliseconds
Input impedance: 600 ohms
Output impedance: 600 ohms
Current consumption: 90ma

Action Pinout

Pin 1: Chassis Ground
Pin 2: Output A +
Pin 3: Link In - (Purple Audio Rack Only - XLR OUT 2)
Pin 4: Output A -
Pin 5: Audio Ground
Pin 6: Link Out - (Purple Audio Rack Only - XLR OUT 2)
Pin 7: Input -
Pin 8: Input -
Pin 9: Input +
Pin 10: Input +
Pin 11: Audio Ground
Pin 12: +15 or 16VDC 90ma
Pin 13: Audio Ground
Pin 14: -15 or 16VDC 90ma
Pin 15: NC (+48VDC)