Calibrating the MMG
Requires small flat head screw driver or trimmer tool, Square Wave reference signal, monitors. If available, an oscilloscope and
DVM are useful.
All trimmers are accessed from the left and right sides of the module. This will require the module to be lifted out of the system for
calibration. It is recommended that the module rest outside the case on a non-conductive surface during calibration.
MODE (trimmer 1)
1. Apply Square Wave at around 220hz (A3) to AC IN. Set FREQ to Full CW. Q and MODE to Full CCW. Set Attenuator so Over
Load indicator is just about to light, but is NOT lighted. This is around 3.65VAC RMS.
2. Patch a dummy cable to MODE CV IN (cable that is not connected to anything on other end).
3. Set MODE and FREQ panel control to full CW (100%).
3. Monitor Signal OUT at comfortable volume.
4. Adjust Trimmer 1 until sound is as thin as possible. Using oscilloscope, this could be verified visually.
FREQuency (trimmer 2) NOT RECOMMENDED
1. Apply Square Wave at around 220hz (A3) to AC IN. Set FREQ to Full CW. Q and MODE to Full CCW. Set Attenuator so Over
Load indicator is just about to light, but is NOT lighted. This is around 3.65VAC RMS.
2. Patch a dummy cable to MODE CV IN (cable that is not connected to anything on other end).
3. Set FREQ panel control to around 10 o' Clock. Monitor Signal OUT at comfortable volume.
4. Adjust trimmer 2 so sound is audible, but harmonics are severely damped. The Square Wave should look and sound like SINE
wave at this point. Using DVM should measure from 2.25 to 4.1 VAC RMS.
5. Set FREQ panel control to Full CW (100%).
6. Adjust trimmer 2 so sound is as bright as possible. Using a scope observe sharpening of edges on the square wave.
7. Check the Response of the FREQuency panel control. At the lower end the sound should start to turn ON in the first 20% of the
knob rotation. At the top end the harmonic content of the signal should continue to be revealed for the entire rotation up to
full CW. (100%). Repeat steps 3 thru 6 to achieve best response.
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Содержание MMG
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