Purple Audio Action 500 Series FET Compressor

The Purple Audio 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.

The Specifications:

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