User Manual

Calibrating the MMG (continued)

Q (trimmer 3)

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. FREQuency panel control to around 2 or 3 o' clock. Monitor Signal OUT at comfortable volume.

3. Set Q panel control to 50%. Q LED should not be lighted. Resonance should be clean.

4. Continue to turn Q panel control clockwise and observe Q LED lighting and resonance increasing in amplitude and

distortions (due to clipping in the resonance circuit).

5. Adjust trimmer 3 to taste. At Make Noise we set so first 50% of Q rotation is clean resonance, and second half of Q

rotation is dirtier resonance. Using scope observe clipping and amplitude.

Automatic Gain Control AGC (trimmer 4)

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

OverLoad indicator is just about to light, but is NOT lighted. This is around 3.65VAC RMS.

2. FREQuency panel control to around 2 or 3 o' clock. Monitor Signal OUT at comfortable volume.

3. Turn Q panel control clockwise and observe Q LED lighting and resonance increasing in amplitude and distortions (due to

clipping in the resonance circuit).

4. While the resonance is increasing the overall loudness of the signal should increase as well, but not to the point of

dis-comfort.

5. Adjust trimmer 4 to taste. Clockwise trimming will result in LESS AGC action. At Make Noise we set so a 3.65V AC

RMS signal at Q setting 0% (no resonance) results in a 4.1V AC RMS signal at Q setting 100% (full resonance).

6. The original QMMG had NO AGC. To achieve this behavior on the MMG, set trimmer 4 to full Clockwise.