WhitakerAudio JC Whitaker 20 W Stereo Integrated Audio Amplifier, Manual

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WhitakerAudio
3.2 Transistorized Stereo Preamplifier Module
The preamplifier PWB is mounted along the side of the chassis adjacent to the left channel
amplifier board (amplifier board #2). This location places the sensitive input circuits as far away
as possible from noise sources. The preamplifier PWB is a four-layer device with the outer layers
assigned to signal-carrying traces and the inner two layers assigned to ground and V+. This makes
for a very efficient layout and maximizes hum and noise suppression on the board.
The connection point codes are detailed in Table 3.5.
Table 3.5 Transistorized Preamplifier PWB Connection Wiring Codes
PWB Code Function Connection Color Code Notes
GND Ground Black Connected to main ground
point
40Vdc DC power input Yellow 40 V dc maximum voltage
input. Connects to V+ source
on power management PWB.
GND Ground Black Ground connection to pream-
plifier daughter board
V+ 24 V dc bus Yellow V+ connection to preamplifier
daughter board
CONN100 Phono input, right White Pin 1
GND Shield Pin 2
CONN101 Phono input, left White Pin 3
GND Shield Pin 4
CONN102 Phono out, right White Pin 1
Phono out, left White Pin 2
GND Shield Pin 3
GND Shield Pin 4
CONN103 Tone control input, right White Pin 1
Tone control inputl left White Pin 2
GND Shield Pin 3
GND Shield Pin 4