ALM-018 - ‘MUM M8’
Calibration
There are two trimmers on the rear on the module which can be used to adjust the
minimum cut off frequency for the filter. Because of the filters architecture, too low a
cut off frequency will introduce high pitched noise into the audio signal (from the
filters controlling clock signal).
The top trimmer (marked ‘FREQ OFF ADJ’ ) sets the ‘base’ cut off frequency - i.e the
cut off will effect the main control knob on front of module turned full counter
clockwise and no CV inputs patched. The lower trimmer (marked ‘FREQ MIN ADJ’) hard
limits the minimum frequency of the filter (from knob or cv input). The trimmers are
adjusted with a small flat head screwdriver.
To calibrate;
1. Turn filter knob full counter clock wise (CCW), Resonance knob full CW - so filter
is in self oscillation.
2. Turn top ‘FREQ OFF ADJ’ trimmer full CCW. Turn lower ‘FREQ MIN ADJ’ trimmer
full CW. You should now hear no resonance but the clock noise.
3. Turn ‘FREQ OFF ADJ’ CW until you can hear just resonance and so that the clock
noise has subsided (approx 1/4 to 1/3 of a turn)
4. Turn ‘FREQ MIN ADJ’ CCW to just before the point it affects the resonance
frequency.
Note the module is pre calibrated at the factory but by all means adjust to taste!
!
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