VAC PA160 Mk I - Manual (Page 3)

3
Unpacking
Do not lift the PA160 by the transformer cans!
Each tube socket on the amplifier is covered by a small round sticker. The color of this sticker corresponds
to the color of the sticker on a tube. Fit each tube into the matching socket, first removing the sticker from
the tube and socket. Handle tubes by the bases, not the glass. The bias levels for the output tubes have been
factory set, but should be checked during the installation procedure.
Installation
Physical requirements:
1) Provide adequate ventilation - allow at least 3 inches above and 1 inch to each side.
2) Do not place in a completely enclosed cabinet.
3) Do not stack other equipment on top of the VAC units.
4) Do not operate on carpet or any other surface that might block air flow.
5) The chassis and power transformers will become hot in normal use.
6) Do not allow the chassis of the VAC components to touch any metal parts, such as the frame of an
equipment rack. This might create a parallel ground path that will degrade the sound of your system.
Electrical connections:
1) Complete all installation steps before plugging the amplifier into the AC mains supply.
2) Connect signal inputs to the power amplifiers. Single ended interconnect cables equipped with RCA
phono plugs or XLR cables (balanced or unbalanced sources) provide the input to each channel -
DO NOT CONNECT TO BOTH INPUTS AT THE SAME TIME.
3) Connect loudspeakers between the appropriate pair of binding posts on the back of the power
amplifiers. Most popular speaker cables can be accommodated by the output terminal strips. Output
impedance matching is available for loads of 2, 4, and 8 ohms. Connect one lead of the speaker
cable to the "G" position, and the other to either 2, 4, or 8. The "G" terminal is at ground potential,
and the amplifier does not invert phase.
4) Do not connect two amplifier outputs to each other.
5) Connect the AC cord to the power source indicated by the configuration card under the fuse (100
volts AC, 120 volts AC, 220 volts AC, or 240 volts AC at 50 or 60 Hertz).
6) Follow the BIAS procedure described in this manual to set the idle current. Check the idle current
at 1 minute, 30 minutes, 1 hour, and 2 hours. Also, read the section entitled INSTALLING NEW
OUTPUT TUBES.
7) Do not operate the amplifier unless connected to a loudspeaker or load resistor.
8) Do not switch on an unmuted preamplifier or source component when the amplifier is operating. The
turn-on surge from an unmuted preamp could potentially damage the PA160, or cause the PA160
(or most high powered amplifiers) to deliver enough signal to damage the loudspeaker.
9) Check that the tube type switch is set to match the output tubes fitted.