Manley СORE REFERENCE CHANNEL STRIP - MCORE001-025 4/2014 - 5/2014 - Manual (Page 13)

c o r e
i) CALIBRATION OF VU METER:
1- Feed a balanced sine tone @ 1 KHz, +4dBu (1.228V RMS) from an audio tone
generator/oscillator into the LINE INPUT XLR.
2- Use your audio analyzer and/or, set your voltmeter to read volts AC and put it at the output of
XLR “OP1”, and start bringing up the Input level attenuator, until you have +4dBu (1.228V
RMS) at the output XLR “OP1”. Same level as the input signal from oscillator (unity gain)
3- Use the VU meter select switch to read “OP1”. Adjust VR16 (OP1 ZERO VU) so the meter reads
“0” VU.
4- Use the VU meter select switch to read “GR”. Adjust VR11 (GR-ZERO) so meter reads “0” VU.
ii) CALIBRATION OF OPTO COMPRESSOR:
1- Make sure the output level at XLR “OP1” is still +4dBu, and meter reading for “OP1” is “0” VU.
2- Move your voltmeter (volts AC)/Audio Analyzer to output XLR “OP2”.
3- Use the VU meter select switch to read “OP2”.
4- Adjust the OUTPUT GAIN control for an output level of +4dBu (1.228V RMS) at “OP2”. Meter
reading for “OP2” should be “0” VU.
5- Switch IN the opto compressor.
6- Adjust VR6 (GR-AUDIO) for a gain reduction of 3.5dB at “OP2” (output XLR “OP2” will read
+0.5dBu)
7- Use the VU meter select switch to read “GR”.
8- The VU meter should read -3.5 if not, adjust VR9 (GR-METER). Verify that VU “GR” and audio
“track” within .2dB
9- Repeat steps 6 to 8.
10- Move the compression control to “MAX”. Verify that VU “GR” and audio “track” within .5dB
11- Switch out the opto compressor (BYPASS).
iii) CALIBRATION OF PEAK LIMITER:
1- Make sure the output level at XLR “OP2” is still +4dBu, and meter reading for “OP2” is “0” VU.
2- Turn OFF your audio generator/oscillator temporarily to complete next step.
3- Switch your voltmeter to read volts DC. Locate test point TP13 and use your voltmeter to check
for a voltage reading of +9.0Vdc (+/- 0.1Vdc), if not adjust VR15 (LIM REF V.). Locate test
point TP14 verify a voltage reading of -9.0Vdc (+/- 0.1Vdc).
4- Locate test point TP20, check for a reading of -4.4Vdc (+/-0.3Vdc), if not adjust VR12 (LIM CV)
5- Turn audio generator/oscillator back on.
6- Make sure the output level at XLR “OP2” is still +4dBu, and meter reading for “OP2” is “0” VU.
7- Move the limiting control to “MAX”. Peak limiter red LED indicator should turn ON (+/- 1.0dB).
Decrease oscillator output level by 2dB, LED indicator should turn OFF.
8- Return the limiting control back to “MIN”. Restore oscillator output level back to +4dBu.
9- Use the VU meter select switch to read “GR”.
10- Increase the oscillator output to +21dBu. Peak limiter red LED indicator should turn ON (+/-
1.5db). Decrease oscillator output level by 2dB, LED indicator should turn OFF.
Note-1: if you do not have enough output level coming from your oscillator, then increase the signal level
coming into the CORE by adjusting the INPUT LEVEL ATTENUATTOR control. Bring up the input level
attenuator, until you have a reading of +21dBu at the output XLR “OP2”.
Note-2: The Manley CORE Peak limiter section was designed to automatically “kick in” according to
specific output levels at the main output “OP2”.
LIMITING control knob set at:
MIN = +20dBu* (+/- 1dB)
MAX = +3.5dBu* (+/- 0.5dB)
* “fixed” per design, and cannot be changed. It is possible if a customer requests.
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