Page D-5
X-Rack Dynamics Module
D.4.3 Compressor Threshold
Adjustment: 1. Connect the level meter to the Output and set the oscillator level for
–28.35dBu.
2. Measure the DC voltage at test point TP14 relative to 0VAand adjust VR9
(COMP_THOLD) for 0V ±10mV.
D.4.4 Compressor Law
Adjustment: 1. Set the oscillator level for +20dBu.
2. Connect the level meter to the Output. Check for +20dBu ±0.5dB.
3. Set the compressor ratio control fully clockwise and press in the
compressor FSTATT and PK switches.
4. Adjust VR10 (COMP_LAW) for a level of 14dBu ±0.1dB.
5. Reset the compressor ratio control fully anti-clockwise.
D.4.5 Gate Threshold
Adjustment: 1. Set the oscillator level for +10dBu and connect the level meter to the
Output.
2. Set the gate/expander to ‘gate’ by releasing the EXP switch, set the gate
range and gate threshold controls fully clockwise.
3. Adjust VR8 (GATE_THOLD) so that the gate just switches on.
4. Check this adjustment by changing the oscillator level a little. Re-adjust
VR8 if necessary so that the gate just opens when a +10dBu signal @ 1kHz
is applied.
D.4.6 Output Balance
Equipment Required: Calibrated audio oscillator, audio level meter and a ‘balance’ adaptor (see
below).
Test Signal: 1kHz sine wave at +24dBu.
Input and Output: Oscillator to the Input of the channel being tested, Output to the level
meter via the ‘balance’ adaptor.
Unit Setup: Ensure that all front panel switches are off and all controls are set fully
anti-clockwise.
Adjustment: Connect the test equipment to the each channel in turn and adjust VR13
(BAL) for minimum level (< 55dBr).
D.4.7 ‘Balance’Adaptor
For the output balance adjustment, a ‘balance’
adaptor such as that illustrated here will be
required. This adaptor consists of a pair of close
tolerance resistors in an in-line cable and is
used to sum together a balanced output in
order to correctly adjust the level balance of the
measured output; perfect balance should result
in complete signal cancellation.
5K01**
5K01**
2
3
1
2
3
1
0V
+
–
0V
+
–
To measuring
equipment
From unit
under test
1
2
1
Resistor tolerance should ideally be 0.01%
Absolute level measured will depend upon the input
impedence of the measuring equipment.
1.
2.
Note