Installing and Wiring the Speaker Jack
Step 1
– Install the 1/4” Switchcraft 11A jack into the appropriate speaker
jack chassis hole. Place the lock washer (the washer with the teeth) on the
inside of the chassis.
Step 2
– Trim the black wire from the output transformer to the edge of the
chassis. Strip and tin the end of this wire and solder it to the “sleeve”
terminal of speaker jack (photo 6.15a).
Step 3
– Strip and tin the end of the 3” yellow wire coming from pad “i”
on the electronics assembly. Connect it but don't yet solder it to the “tip”
terminal of the speaker jack (photo 6.15a).
Step 4
– Check impedance of speaker and select appropriate matching
output transformer tap (see below caution).
Step 5
– Trim, strip and tin the end of this wire and solder it, along with the
previously mounted yellow wire to the “tip” end of the jack.
Step 6
– Cap off the end of the unused output transformer tap with a small
piece of electrical tape or heat shrink tubing (photo 6.15b).
Proceed to 6.16
Wiring the Rectifier Tube Socket
Step 1
– Strip and tin the end of the red wire
with the yellow line on it coming from the power
transformer. Solder this wire to the solder
terminal nearest the rectifier socket. This same
terminal has the green wire from the power cord
connected to it (photo 6.16a).
Step 2
– Strip and tin the two solid red wires
from the power transformer. Solder these to
pins 4 and 6 of the rectifier tube socket. You will notice there is also
red and white striped wires. These wires are for running the amp at
lower voltage. This will give the circuit a different sound and you can
experiment with both, but only ever connect the solid two red wires or
the red and white striped wires to the stated pins. The unused wires
must have their end covered with a small piece of the provided
heatshrink tubing (photo 6.16b).
Step 3
– Strip and tin the two yellow wires from the power transformer.
Connect these two wires to pins 8 and 2 of the rectifier tube socket.
Apply solder to pin 2 but do not yet apply solder to pin 8 (photo 6.16b).
Step 4
– Trim the red wire from pad “d”. Strip and tin this wire and
connect it to pin 8 of the rectifier tube socket. Do not solder just yet
(photo 6.16b).
Step 5
– Trim the red wire from the output transformer to the edge of
the chassis. Strip, tin and solder to pin 8 of the rectifier
tube socket
(photo 6.16b). All three wires should now be soldered.
Step 6
- The remaining black wires (which are the unused multi-
voltage taps) of the power transformer should be trimmed and capped
off with either electrical tape or preferably heat shrink tubing (photo
6.16c). Do not trim the green wires yet.
Proceed to 6.17
6.15
photo 6.15a
sleeve
tip
CAUTION
For 8 ohm impedances, use the green wire. For 4 ohm impedances,
use the yellow wire. Running this amp into an incorrect load can
damage the output transformer and the power tubes.
photo 6.15b
6.16
16 TubeDepot.com
photo 6.16b
photo 6.16a
