WMD - Multimode VCA

This very practical module has been designed with the goal to give you a versatile dual VCA with a lot of possibilities. Besides the use as a two individual VCAs with switchable characteristics the module features mix outputs, a number of useful combinations of both VCAs like crossfade, panner etc. Besides this you´ll find useful normalizations and a saturation stage.

The Multimode VCA module integrates two identical VCAs based on OTA operation amplifiers you can independently swithc between exponantial and linear response. An other switch activates the AC- or DC- coupling which eliminates DC offset for both VCAs simultaneously. Thus the VCA is suitable for controlling both audio and CVs. Each VCA has a Bias control for setting the basic level and a CV input with a biploar attenuator.

Both units can be used as separate VCAs but the normalizations and routing options for CVs and inout signalstrn the Multimode VCA into a crossfader, panner, bipolar VCA (voltage controlled polarizer) and many more:

• Split Mode: The MMVCA serves as two separate VCAs in this mode. Set the "B CV Source" switch to "B=B". Plug into both VCAs and use separate CV, or just the CV from the A jack.
• Bipolar VCA: This mode requires the use of both A and B channels. Set both the "B CV Source" and "In B Normal" switches to "B = -A". Plug CV and signal to be polarized into the A side. Monitor from A B. The output will be inverted through zero at 0V CV.
• Crossfade - Run two inputs to the A and B Jacks. Set the "Xfade/FTZ" switch to "Xfade" when in linear operation. Set the "B CV Source" switch to "B = -A". Control crossfade with the CV A jack. Monitor on A B Out. Works similarly in Exponential mode.
• Fade Through Zero: Both VCAs set to Linear mode. Set the "Xfade/FTZ" switch to "FTZ". Set the "B CV Source" switch to "B = -A". Control with CV A jack. Monitor on A B Out. This fades B to silence to A as CV goes positive.
• Pan: Run audio into the A jack. Set the "In B Normal" switch to "B=A". Set the "Xfade/FTZ" switch to "Xfade". Monitor in stereo on both A and B Outputs. CV A will move right to left (B to A) as CV goes positive.
• Spread Pan: Run audio into the A jack. Set the "In B Normal" switch to "B=A" and the "B CV Source" switch to "B=B". Audio in A, CV in A. Oppose the CV knobs to control response to CV. Use the Bias knobs to set the amount of spread. Monitor in stereo on both A and B Outputs.
• Spread Crossfade: Run audio into both the A and B jacks. Set the "In B Normal" switch to "B=A" and the "B CV Source" switch to "B=B" . Audio in A, CV in A. Oppose the CV knobs to control response to CV. Use the Bias knobs to set the amount of spread. Monitor the A B.

specail features of controls and jacks:

• Is the signal source for VCA B the inverted A-Signal then the CV-B socket has no function anymore
• The XFade / FTZ-switch works only in linear mode
• In linear and FTZ modes the Bias controls have their zero position in the middle. In X-Fade mode the zero position is fully CCW.