Phase Shifter

Discrete transistors find there way into phase shifters in two ways. Most commonly, JFETs can be used as the variable resistance component. Less commonly, discrete transistors, typically BJTs can be used as the splitting/amplifying element. The few examples of pre-op amp phase shifter effects had to use discrete transistors. Really early versions used vacuum tubes for the active element and obsolete varistors as the variable resistors.

BJT used as the splitting/amplifying device, optocoupler variable resistor:

Musser Ampli-Celeste

Uni Vibe

Matched JFET phase shifters:

Maestro Phase Shifter

MXR Phase 90

Electro Harmonix Bad Stone (early versions)

Not to be confused with phase shift oscillators, found under the oscillator page.