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.
Input attenuator feeding input transformer
Output level control
and output tricolor LED metering
Eight LED GR metering
including "All buttons in" mode
Attack and Release controls
Compression on/off switch
Discrete signal path
Over Current Resettable Fused (prevents any module problem from affecting
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.
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
Release time: Continuously Variable from over 1.1 seconds to 50
Input impedance: 600 ohms
Output impedance: 600 ohms
Current consumption: 90ma
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: NC
12: +15 or 16VDC 90ma
Pin 13: Audio Ground
Pin 14: -15 or 16VDC 90ma
Pin 15: NC (+48VDC)