WhitakerAudio 60 W Stereo Power Amplifier, User And Assembly Manual

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60 W Stereo Power Amplifier
– Mount the ten 3/4-inch long standoffs on the foil side of the board using the 4-40 hardware
provided. Use a lock-washer on the screw head (component side) of the board. Standoffs
are positioned at the four corners of the PWB and on each side of the tube sockets. Note
that one of the standoff sets includes a ground lug. Place this lug and standoff in the corner
of the PWB closest to the XFMRCT tab. The ground lug goes on the component side of
the board. The screws should be finger-tight for now.
In the following steps the tube sockets will be mounted and connected to the PWB pads.
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. Prior to mounting the octal sockets (V2 and V3), bend pins 2 and 7 (the heater
connections) outward away from the center of the socket. This will facilitate connections
later in the process. 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 5.1 shows the pins that should be connected to the PWB.