Vectronics VEC-1680K - Manual (Page 12)

VEC-1680K Owner’s Manual Vacuum Tube Preamp
12
! ! Align and install the DPDT relay at RLY1. Holding firmly in place,
solder all eight pins.
Now, install the preamp's 9-pin ceramic tube socket. As with the relay, these
mounting pins are keyed to ensure proper positioning. Make sure all pins are
firmly seated--and hold the socket in place when soldering.
! ! Align and install the ceramic tube socket at V1 and solder all 9 pins.
Next, install the twisted-pair filament leads to V1. Begin by locating the 4"
length of the orange-and-white twisted hook-up provided with your kit:
! ! Dress each wire at both ends, removing about ¼" of insulation.
! ! Install the white wire at one end at GNDA-1 and solder.
! ! Install the companion orange wire at A-1 and solder.
! ! Install the other end of the white wire at GNDA-2 and solder.
! ! Install the companion orange wire at A2 and solder.
! ! Cut and dress a 6" length of hook-up wire and install one end at FOOT
(this will be connected to the foot-switch jack later on). Solder.
Two shielded audio wires are used for the preamp's high-impedance INPUT and
OUTPUT leads. Shielding prevents these lines from picking up stray AC hum.
Note that only the circuit-board end of the lines are grounded. If both ends were
grounded, it could set up a "ground loop" inside the amplifier enclosure that
would introduce hum and noise. Prepare each cable as shown below:
1/2"
Trim off shield
! ! Prep a 4" length of shielded cable, as shown.
! ! Connect the shield to GND5 and solder.
! ! Connect the inner conductor to OUTPUT and solder.
! ! Prep a 8" length of shielded cable, as shown.
! ! Connect the shield to GND4 and solder.
! ! Connect the inner conductor to INPUT and solder.