Why a linear power supply for the V4?
The heart of the ePot.V4 stepped attenuator & preamp controller is its current controller which is a precision analog op amp that runs on 5 volts. The cleaner the power to this op amp, the cleaner and quieter the LDR current control, the less noise in the overall LDR control system, fewer extraneous sonic artifacts, and better overall performance. The
The rather low line level audio signals (low 1-2 volts RMS) typically present in audio preamps, are susceptible to noise being introduced through external power sources. And even though the power used by the V4 never touches the audio signals directly, this power does flow through the control circuits of each LDR and is thus indirectly able to influence sound quality through any resulting variations in the LDR resistance.
