‘68 Custom Princeton
®
Reverb
(This is the model name for warranty claims)
5
POWER SUPPLY
The line voltage is fed to T2’s primary through the
line fuse, F1, and the inrush current limiter, RT1.
The input voltage is then stepped up or down as
needed, full-wave rectified by dual vacuum tube di-
ode V7 and filtered to produce the 440V, 425V, and
260V B+ voltages for the tubes. Solid state diodes
D6 and D8 will allow the amp to continue to work
even if a short exists across the vacuum tube V7
diode. A 6.3VAC secondary powers the power indi-
cator lamp and the preamp & power amp tubes’
heaters. The rectifier diode filament is supplied by
a separate 5.4 VAC secondary winding.
Bias for the output tubes is supplied by the solid
state half-wave rectifier D7, a resistive divider circuit
(R28, R22 and R2), and filter capacitor C25. R22 is
used to adjust the output tube stage bias voltage to
set the idle current at 23 mA (23 mV across R20 or
R32).
