MST - Dual 2164 VCA

MST - Dual 2164 VCA is a high-quality VCA module with extra tricks that will let you create your own nice flavours of audio or CV signals!

€99.60 €83.00
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mstdvca

MST - Dual 2164 VCA is a high-quality VCA module with extra tricks that will let you create your own nice flavours of audio or CV signals!

MST – DUAL 2164 VCA
The MST - Dual 2164 VCA is a precision AC (audio) & DC (gate triggers or control voltage) Voltage Controlled Amplifier in 6HP. Each channel has a linear or exponential response switch, the exponential resulting in a “poppier” response. Adjustable output level and bleed if you want to mix in your unaffected source audio. Butters your toast all the way to the edge.

Features:

  • Two identical VCA circuits
  • Capable of AC and DC signal processing
  • Linear and Exponential response select switch
  • CV input (1:1 input-output ratio at 5VDC CV input)
  • Signal Input
  • CV 1 normalled to CV 2
  • Signal 1 normalled to Signal 2
  • Bleed level adjustment per channel

Specifications:

Current draw: V+ max 20mA, V- max 17.5mA
Width: 6HP Depth: 3.5 cm (1.75 in)


MST Dual VCA Calibration Instructions

General Patch Setup
The patch we use to calibrate the MST Dual VCA is relatively simple, but calibration requires an oscilloscope, a module that can generate a sine wave, a module that can generate a slow saw wave, a mixer, a mult, and something that can generate a 5v CV signal. The modules that generate your sine wave and slow saw wave can not be the same module, as they need to be a different frequencies.

Plug the sine wave into the mult, and run one output from the mult to the mixer, the other to the VCA. Next, put the output of the VCA to another channel of the mixer. You will need to be able to plug both of these into your oscilloscope, and you can either use a mixer with switches, or just plug and unplug each channel separately.

LEVEL ADJUSTMENT
The first thing we need to set is the overall output level. Make sure you have:

No CV input
Turn level fully CW
Turn Bleed fully CW
With just the sine wave going into the VCA (channel 1), in linear mode, turn trimmer RT201 so that the output level of the VCA matches the output level of the sine wave. This will set the output for both channels.

Channel 1
Now we will set the CV for channel 1.

Turn Level fully CW
Turn Bleed fully CCW
Add 5V signal into CV input of channel one
With the sine wave still in channel 1’s input, adjust trimmer RT202 so that the output level of the VCA matches the output level of the incoming sine wave.

Channel 2
Now we will set the CV for channel 2. Bring each plug from channel 1 to the corresponding jack in channel 2.

Turn Level Fully CW
Turn Bleed Fully CCW
Use the same CV input from the previous step, plugged into channel 2’s CV in.
Now adjust trimmer RT203 so that the output level of the VCA matches the output level of the incoming sine wave.

Exponential Calibration: (works for both channels)

Keep sine wave input in channel 2 input
Plug your sawtooth wave into channel 2 CV in.
Turn Level Fully CW
Turn Bleed Fully CCW
Put the switch in Linear mode. (down)
With it set up like the above bullet points, look at the oscilloscope’s screen. You should see something similar to the picture below. We call that the ‘Linear Christmas tree’. Yours should look very similar.

MST VCA Linear

Flip the switch on the VCA into exponential mode, and then adjust RT200 until you see a new ‘christmas tree’ that looks like the one below. The edge of it should have a nice exponential curve to it. Make the level of the exponential either match, or about .5 volts higher to get a nice ‘pop’ sound from your VCA.

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