synthrotek vac pac diy kit price : $17.99

have you ever wanted to add control voltage to a parameter on your synth or circuit bent toy? now you can!

the vac pak is a vactrol-based control voltage to variable resistance circuit.

connect your cv source to the input jack. set the scale and offset trim pots to dial in your optimal resistance, with a range between ~300 ohms to ~10m (all vactrols are a little different in range). connect the wires from j4 to your circuit to make a variable resistor. daisy-chain multiple vac paks to the same power source using the remaining connector (either j2 or j3). power the vac pak with a 9v battery clip (wired to j2 or j3) or with your circuit's on-board voltage source (wired to j2 or j3). an onboard 5v regulator allows the vac pak to be powered with 6-18v dc. caution: do not exceed +10v dc on the cv input, more may burn up your vactrol!