Weekly Q&A: Answers | Week of November 13, 2023

"An Audio Signal is Like a Fine Pastry..."

Q: Hello. My question concerns the pros and possible cons of using a passive shunt-to-ground attenuator preamp, which employs a roughly 50 position volume selector switch. Only one resistor is in the output signal path in either channel (output impedance is 2.5K ohms); all other resistors used in the selector switch are metal film; the switch uses make before break silver contacts. Internal (very short) wiring in the preamp is 6/9’s ONO copper. The passive preamp sits between two 60 watt tube monoblock amps (50K ohm input impedance) and either a solid state DAC with a 3.1 VRMS output voltage at the recommended DAC volume setting or a solid state phono stage with output voltage up to 24 VRMS. (There is thus more than enough voltage to drive the speakers loudly, if desired, even with very low voltage MC cartridges.) All interconnects are short (1.5 meter or less), and all low capacitance. I understand that the impedance between the amps and the passive is well matched, and should not re…