Author Topic: Variable Impedance Control (Mic Preamp)  (Read 204 times)

Mr.Kite

Variable Impedance Control (Mic Preamp)
« on: September 27, 2020, 04:41:01 PM »
Hi,

I built this (https://www.youtube.com/watch?v=r1yPMDHiRuc&ab_channel=DIYRecordingEquipment) Variable Impedance control and I'd like to hear your opinion about the design\wiring.

I tried it with an SM57 (used to mike my AC15) with a Presonus Tube Pre V2 (valve section disengaged): it alters the tone slightly, losing some detail, gaining some warmth. Also the transient response seems a bit slower with lower settings, and it starts to lose quite a bit of output with very low settings (under 200-300 Ohm or so).

Basically it inserts a variable resistor (a 5k Log pot in my case) between the + and - signals of the TRS\XLR connection, in parallel with the input impedance of the mic preamp. Sorry for the dumb question, but is this the correct wiring for an Impedance Control in your opinion?
« Last Edit: September 27, 2020, 06:16:05 PM by Mr.Kite »