Manley СORE REFERENCE CHANNEL STRIP - MCORE026 and up 7/2014 - 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”. Star tbringing up the Input level attenuator until you have +4dBu (1.228V
RMS) at the output XLR “OP1”. This will be the 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 that 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 ELOP COMPRESSOR:
1- Make sure the output level at XLR “OP1” is still set for +4dBu, and the meter reading for
“OP1” is “0” VU.
2- Move your voltmeter (Volts AC)/Audio Analyzer to read the 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 COMPRESSOR.
6- Adjust VR6 (GR-AUDIO) for a gain reduction of 6dB at “OP2”. (The output XLR “OP2” will read
-2 dBu).
7- Use the VU meter select switch to read “GR”.
8- The VU meter should read -6. If not, adjust VR9 (GR-METER). Verify that VU “GR” and audio
are within 0.2dB of each other.
9- Repeat steps 6 to 8.
10- Switch out the COMPRESSOR by switching it to BYPASS.
iii) CALIBRATION OF PEAK LIMITER:
1- Make sure the output level at XLR “OP2” is still reading +4dBu, and the 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 on the front panel PCB and use
your voltmeter to check for a voltage reading of +9.0VDC (± 0.1VDC). Adjust VR15
(LIM REF V.) So that TP13 reads 9.0 VDC. 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), Adjust VR12 (LIM CV) so
that TP20 = -4.4 VDC
5- Turn audio generator/oscillator back on.
6- Make sure the output level at XLR “OP2” is still +4dBu, and the 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. The 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. The Peak limiter red LED indicator should turn ON
(±1.5db). Decrease oscillator output level by 2dB. The 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 ATTENUATOR 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”.
When the LIMITING control knob is set at MIN the LIMIT threshold will be at +20dBu (± 1dB)
When the LIMITING control knob is set at MAX the LIMIT threshold will be at +3.5dBu (± 0.5dB)
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