WhitakerAudio 60 W Stereo Power Amplifier, User And Assembly Manual

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60 W Stereo Power Amplifier
The PWBs are connected to the chassis through the mounting holes for the vacuum tubes. The
tube sockets are conventional chassis-mounted devices, with jumper leads extending from the
active pins to the PWB. The sockets are held away from the PWB using standoffs. This approach
permits the sockets to be firmly mounted on the chassis, rather than being physically supported by
the PWB. Furthermore, with this mounting arrangement radiated heat from the tubes is dissipated
above the chassis, preventing heat damage to the PWB over time.
A separate, small PWB is used at each of the speaker terminals to facilitate connection of the
output transformer secondary leads. The board layout is shown in Figure 3.2.
TERM5 6.3 V filament to amplifier
boards Green
TERM6 6.3 V filament to amplifier
boards Green
TERM7 Bias voltage output to
amplifier boards White
TERM8 Same as EXT-FILa
TERM9 Same as EXT-FILb
TERM10 Bias test point
R60a R60 potentiometer, high White
R60 arm R60 potentiometer, arm White
R60b R60 potentiometer, low White
800CT 400-400 V center-tap Red/yellow
400V 400 V ac, 288 mA, plate
winding Red Direct-wire to V51 socket
optional
400V 400 V ac, 288 mA, plate
winding Red Direct-wire to V51 socket
optional
GND Ground Black
5VH2a 5 V ac, 3 A, heater Yellow Direct-wire to V51 socket
optional
H2CT 5 V filament center-tap Yellow/black
5VH2b 5 V ac, 3 A, heater Yellow Direct-wire to V51 socket
optional
L51 in Choke Black
L51out Choke Black
V51k Cathode connection of V51 Not connected
5Vdc 5V dc source yellow
GND Ground Three GND posts are
provided on the board.
Table 3.2 Power Supply PWB Connection Wiring Codes