Filter
Top Products
Page 12
XLogic Multichannel Compressor Owner’s Manual
Distortion Null
Equipment Required: Calibrated audio oscillator, audio distortion analyser and oscilloscope
Test Signal: 1kHz sinewave at +24dBu
Input and Output: Oscillator to the Input of the channel being tested, Output to the distortion
analyser. Use the oscilloscope to monitor the measured signal.
Adjustment: 1. Connect the +ve input of the analyser to the test point as shown below and
connect the –ve input of the analyser to a 0VA test point. Note that the circuitry
at this point is balanced and so there are two measurements and two adjustments
per channel. Adjust for minimum THD (< 0.007%).
Input Measure Adjust
Left (+ve) TP31 VR24
Left (–ve) TP32 VR23
Right (+ve) TP29 VR22
Right (–ve) TP30 VR21
Centre (+ve) TP27 VR20
Centre (–ve) TP28 VR19
LFE (+ve) TP21 VR14
LFE (–ve) TP22 VR13
Left Sur (+ve) TP23 VR16
Left Surr (–ve) TP24 VR15
Right Surr (+ve) TP25 VR18
Right Surr (–ve) TP26 VR17
2. Finally, re-connect the analyser to each output in turn and adjust the +ve
distortion null to see if any reduction in THD can be achieved.
VCA Gain Adjust
Equipment Required: Calibrated audio oscillator, audio level meter, oscilloscope and a (digital) DC
voltmeter
Test Signal: 1kHz sinewave at +20dBu
Input and Output: Oscillator to the Input of the channel being tested, Output to the level meter. Use
the oscilloscope to monitor the measured signal.
Unit Setup: 1. Switch the Master Fader IN.
2. Using the DVM, measure TP5 on the upper card (629607) and adjust the front
panel Master Fader for –2.00V ±1mV (which equates to 40dB attenuation).
Adjustment: 1. Connect the audio level meter to each output in turn. Measure each channel,
adjusting the appropriate preset for –20dBu ±0.1dB (which equates to 40dB of
attenuation).
Input Adjust
Left VR30
Right VR29
Centre VR34
LFE VR36
Left Surround VR27
Right Surround VR28