2 slot 500 series microphone preamplifier and compressor
Its compression features , key components and schematics are the same found on the Heritage Audio classic 2264E compressor.A fully featured 60dB 1073 mic preamplifier has been implemented when compression is not needed. Phantom power is also available.
Its audio path is fully discrete Class A, 2n3055 driven, transformer balanced. All controls are stepped on rotary switches for easy recall and high precision. A high pass filter has been added on the sidechain to avoid bass signals to ride the compression.
It features discrete inputs for Compression / Line amp (Left slot input) and mic (Right slot input).
Output in both cases is on the Left slot output.
Gain Reduction Meter: Shows the compression amount up to 20dB.
DYN switch: Enables compression functions.
High Pass switch: Enables high pass filter on the sidechain circuit.
MIC switch: Enables Mic input and overrides Compression / Line input functions.
Compress Recovery switch: Switches between 6 time constant options, 100ms, 400ms, 800ms, 1500ms, Auto1 (100ms on peaks, 2secs on program material) and Auto2 (50ms on peaks, 5secs on program).
Compress Threshold Stepped control: Sets the minimum level at what compression happens, from +12dBU down to -12dBm in variable "smart" steps).
Compress Ratio Switch: Allows the user to choose between 5 different compression ratios, 1.5, 2, 3, 4and 6:1, and a LIM option.
MIC Gain Stepped control: In 5dB steps from 35 to 60dB.
Gain Makeup Stepped control: In 2dB steps from 0 to 20dB.
LINK switch: Allows the module to be linked to compression bus.
Microphone input impedance: 1200 Ohm .Input is transformer balanced and floating.
Line input impedance: 10KOhms bridging, transformer balanced and floating.
Output impedance: Less than 75 Ohms, transformer balanced and floating, 600 Ohms terminated.
Maximum output: Greater than +26dBm , 600 Ohms terminated.
THD: Less than 0.025% at 1Khz, Less than 0.05% at 100Hz.
Frequency response :20Hz (+0.3dB) to 20Khz (-0.2dB).
Maximum Microphone Gain: 60dB.
Maximum Line Gain: 20dB.
Maximum Power consumption: Less than 110 mA @+-16VDC.