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RE: My New DIY Passive Preamplifier

Posted by fastcat on February 9, 2023 at 13:32:25:
The resistor trick here is having 1/2W 100K Takman REY metal film resistors between the input and the wiper contact, and the wiper contact and ground. I believe this was first discovered by the late Bob Crump. The TKD pot becomes a parallel variable resistor with the fixed resistors. The actual input value is only lowered slightly. I have not measured the capacitance of the interconnects, but they are very low, and 0.5 meter or less in length. The input of my amplifier has a very low value capacitor in series, and with 120 K Ohm input impedance to form a 1st order high pass at 94 Hz.