Dual Voltage Controlled Amplifier/Attenuator

Just dropped today; our redeveloped dual voltage controlled amplifier/attenuator. Two linear response VCAs in 2HP with accuracy improved from version 1. The addition of inverting CV inputs and the optional 'auto-bias' mode make the module very useful for ducking / side-chain-type applications as well as more standard VCA use. It is unity gain at 5V but can accept control voltages up to 10V.

Introductory offer: 15% off this weekend (ends Sunday 11:59pm IST (GMT+7).

A dual linear voltage controlled amplifier/attenuator now in 2HP, based on the LM31700 chip.

Version 2 is very similar to version 1 - it is pre-offset to be normally closed, a positive voltage applied to the CV input will amplify any AC or DC signal present at the input, with +5V giving unity gain. It will accept voltages of up to 10V amplifying the signal up to x2.

New to version 2 are the CV INV. Inputs. This inverts any CV and sums it with the non-inverted CV input. For example inputting a positive voltage at CV INV. will have no effect on the VCA if it is already closed (I.e if there is no positive voltage at the CV input) but if there is a voltage at the CV input acting to amplify the signal, then a positive voltage at CV INV. input can be thought of as a secondary subtracting or ducking control.

This is great for a side-chaining type effect. For example use it as a standard VCA for a bass voice, shaped via the CV input, then put an envelope corresponding to your kick drum into CV INV. to duck the bass pattern as the kick-drum sounds.

Furthermore a jumper on the board allows you to set ‘auto-offset’ to the CV INV. control (a single jumper affects both gates). When the unit is set up like this inserting a jack into CV INV. (even with no signal) automatically applies a +5V offset to the VCA, opening it up at unity gain so that any signal at the input is present at the same level at the output. From there any voltage at CV or CV INV will add to or subtract from this offset point. This is useful for ducking a signal that already has dynamics e.g from a synth voice or the wet output from a reverb/delay unit.

https://www.siammodular.com/takaab-2vca-v2-dual-voltage-controlled-amplifierattenuator

• ? mA +12V
• ? mA -12V
• ? mA 5V
• 36 mm Depth

This Module is currently available.