WhitakerAudio JC Whitaker 20 W Stereo Integrated Audio Amplifier, Manual

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WhitakerAudio
– Mount the ten standoffs on the foil side of the board using 4-40 hardware provided. Use a
lockwasher on the screw head (component side) of the board. Standoffs are positioned at
the four corners of the PWB and on either side of each tube socket. The standoffs should
be finger-tight against the board. For the standoff in the corner of the PWB adjacent to the
L1out terminal, use a #4 ground lug in place of the lockwasher.
In the following steps the tube sockets will be installed and connected. These steps will
require a considerable amount of time and patience. Successful completion is critical to proper
operation of the amplifier.
– Mount the three sockets on their respective standoffs. Pin 1 of the socket can be identified
by a number stamped on the bottom side of the socket. Pin 1 on the PWB is identified by a
square pad. Place the socket in the proper orientation over the PWB so it rests on the
standoffs. The top of the socket (the side the tube plugs into) should face outward. Loosely
tighten the mounting screws. See Figure 5.2 a .
– Install connecting wires from the PWB pads to the tube socket pins. Solder in place.
Materials for these steps can be found in the “Tube Socket Hookup” package. Note that
the PWB contains pads only for the active pins used on the socket. The heater connections
are made separately. The recommended procedure for installing the connecting wires is as
follows:
1) Feed a bare wire from the component side through the pad and into the socket
soldering tab.
2) Crimp in place (see Figure 5.2 b ).
3) From the component side, pull the wire tight and solder in place
4) Trim the excess lead length.
5) Solder the socket tab.
Table 5.2 shows the pins that should be connected to the PWB.