Small Signal Audio Design, 3rd Edition

CHAPTER 7

Preamplifier Architectures

Some sort of preamplifier or control unit is required in all hi-fi systems, even if its only function is to select the source and set the volume. You could even argue that the source-selection switch could be done away with if you are prepared to plug and unplug those rhodium-plated connectors, leaving a “preamplifier” that basically consists solely of a volume control potentiometer in a box. Mind you don’t catch your sackcloth on those heat sink corners, and try to keep the ashes away from the turntable.

I am assuming here that a selector switch will be required, and that gives us the “passive preamplifier” (oxymoron alert!) in Figure 7.1a.

Passive Preamplifiers

A device may have only one component, but ...