WhitakerAudio J C Whitaker 20 W Stereo Audio Amplifier, Manual

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20 W Stereo Audio Amplifier
3.2 Preamplifier Power Supply Module
The preamplifier PWB is mounted along the side of the chassis adjacent to the left channel
amplifier board (amplifier board #2). The connection point codes are detailed in Table 3.5. The
layout of the preamplifier power supply board is shown in Figure 3.5.
Table 3.5 Preamplifier Power Supply PWB Connection Wiring Codes
PWB Code Function Connection
Color Code Notes
GND Ground Black Connected to Amplifier PWB #2 ground
35Vdc DC power input Violet 40 V dc maximum voltage input. Connects
to switched V+ source on Power
Management PWB.
B+ B+ high voltage input Red B+ from Amplifier #1 PWB, typically 350 to
450 V dc.
H-7 AC line hot input Black AC line hot from Amplifier PWB #1
N-5 AC line neutral input White AC line neutral from Amplifier PWB #1
Conn301
1 Ground Black Ground
2 Pilot lamp White 120 V ac
3 Pilot lamp White 120 V ac
4 Auxiliary B+ Red Approxi250 V dc
5 Filament Green 6.3 V ac for heaters
6 Filament Green 6.3 V ac for heaters
7 Interlock Blue Connected to Pin #8 at load
8 Interlock Blue Connected to Pin #7 at load
9 Ground Black Chassis ground