Page K-6
X-Rack Owner’s Manual
4
. Switch BLK in and re-adjust LMF Frequency for maximum level.
5. Adjust VR16 for +18dBu ±0.25dB.
6. Reset LMF Gain to its centre indent position and release the BLK switch.
Re-check the audio level meter for 0dBu.
LF EQ – Maximum Gain
Adjustment: 1. Ensure that the BLK switch is released.
2. Set LF Gain to maximum and select LF BELL. Set the audio oscillator for
8
0Hz and adjust LF Frequency to find the maximum level on the audio
level meter.
3. Adjust VR17 for +15dBu ±0.25dB.
4. Switch BLK in and re-adjust LF Frequency for maximum level.
5. Adjust VR18 for +18dBu ±0.25dB.
6. Reset LF Gain to its centre indent position, release the BLK switch and de-
select LF BELL. Re-check the audio level meter for 0dBu.
K.4.2 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 VR19
(BAL) for minimum level (< 55dBr).
K.4.3 ‘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
