Total Audio Control COMPRESSOR ONE 500 Series, Assembly And User'S Manual

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7) Measure the voltage on TP4 and adjust VR8 until a reading of +85mV is obtained. This trimming is required because the
tolerance of the RMS section of the THAT4301 is +/-3dB. When RMS detectors are linked in multiple compressor setups it
is important that the 0dB reference is the same on each. Using this connection in stereo applications will prevent “image
shifting” due to one channel compressing while the other is not which can be a problem in stereo systems with
independent detectors.
The meter should now indicate 0dBu in all settings of the meter source switch and the output should be 0dBu.
8) Turn the Threshold fully CCW. All the LEDs in the GAIN REDUCTION meter should illuminate.
9) With an input of 0dB, verify the GAIN MAKEUP calibrations when fully CCW and CW (-6dB and +18dB). Also verify the 0
point is correct. Component tolerances may affect this slightly.
This has established that the Compressor is basically working .
10) Now confirm that the signals on the Test Points are close to those in the Table below with NO input signal and the
Compressor switched OUT.
Check all test points using pillar FIX6 as analogue ground reference.
Turn the Threshold knob to be exactly 12.00 o’clock.
Turn the Attack knob to be exactly 12.00 o’clock.
Turn the Recovery knob to be exactly 12.00 o’clock.
Turn the Ratio knob fully CW.
Turn the Gain knob to indicate “0”.
Turn the Dry/Wet knob fully CW.
After applying power, wait a couple of minutes before taking below measurements to allow time for voltages to settle.