Audio Research VS115, Owner'S Manual

Page: 12 / 15

It is important sonically that your entire system be
connected so that the audio signal arriving at the speakers
has correct, or “absolute” polarity (i.e., non-inverted).
Connect the black or “-” speaker terminal to the wire that
connects to the “0” terminal on the VS115. Connect the red
or “+” speaker terminal to the wire that connects to the “4 ”
or “8” terminal on the VS115. and tighten the speaker
terminals securely to ensure best sonic results.
MATCHING : It is important to use as close as possible an
impedance match between the amplifier and speaker for
optimum transfer of power to the speaker with minimum
distortion. In the case of speaker systems with significant
variations in impedance throughout the frequency spec-
trum, such as most electrostatic types, determine the best
impedance match empirically for best overall sonic results.
Connect the VS115 input to the preamplifier or electronic
crossover, using only the highest grade of audio intercon-
nect cables. To avoid sonic degradation use the shortest
practical length of cables.
AC POWER CONNECTIONS: It is essential that the VS115
amplifier be connected to a wall AC power receptacle, or
a similar heavy-duty source. If it is connected to conve-
nience receptacles on preamplifiers
,
etc., the full sonic
capabilities of both the VS115 and the preamplifier may be
compromised.
For the very best sonic performance on domestic 120 volt
circuits, the VS115 should be connected to its own AC
power circuit branch, protected by a 20 amp breaker. The
preamplifier and other audio equipment should be connect-
ed to a different power circuit and breaker. Avoid the use
of extension cords. If they must be used on a temporary
basis, use 12-gauge or heavier cords.
The VS115 utilizes a compatible grounding system that
generally does not require a “ground lifter” adapter plug on
the AC power cord to minimize hum. The power cord on
your VS115 has a standard three-prong grounding plug to
provide maximum safety when it is connected to a ground
wall receptacle. If there is any question regarding the safety
of grounding procedures, be certain to seek competent
help with the installation.
If electronic crossovers or other AC powered equipment is
used with the VS115 it may be necessary to use “ground
lifter” adapters on the power plugs of that equipment to
minimize system hum. Generally, the lowest hum is
achieved when the only direct connection between audio
common “ground” and true earth ground occurs in the
preamplifier, through its grounded power cord. Other
equipment in the system should have some form of isola-
tion to prevent ground loops and associated hum.
Input Connections Warning:
To avoid stress and possible damage to the output
tubes, do not connect or disconnect input cables to
the VS115 amplifier while it is turned on. The pre-
amplifier should also be muted before connecting or
disconnecting input cables to the VS115.
Single-Ended Operation
Single-ended inputs should be used with a preamplifier (or
electronic crossover, etc.) having single-ended outputs
which does not invert overall phase or polarity. When
using single-ended inputs, make sure the shorting jumper
pins supplied for single-ended operation are installed
on the rear panel of the amplifier between the bottom
and right socket holes of the balanced input jack,
on both channels, as shown in the accompanying rear
panel diagram.
Balanced Operation
B a l a n c ed inputs can be used with a preamplifier (or
electronic crossover, etc.) having balanced outputs. When
using the balanced inputs, remove the shorting jumper
pins before connecting balanced XLR connectors. Discon-
nenct any single-ended cables.
Always place the power on-off switch on the panel of
the VS115 in the “O ff ” position before connecting the
power line cord to AC power.
Remote Turn-on Connections
The VS115 has a built-in 12VDC remote turn-on/off circuit
for operation by a master control system in a home theater
or large audio system. Use a 3.5mm (.140") diameter mono
mini plug to connect to the +12V IN jack on the rear of the
VS115. Two identical paralleled jacks are provided to
allow chaining connections to control two or more VS115s
or other equipment.
The +12V IN jack should be connected to the +12VDC
output of the master control system, using a continuous
+12VDC signal at 12mA per VS115 for the duration of am-
plifier on-time. Do not use a momentary or data pulse con-
trol signal.
The front power rocker switch on the VS115 must be off to
use the remote turn-on. The front power rocker switch may
still be used when the remote turn-on is connected, but the
remote will not turn the VS115 off if the front power rock-
er switch is left on. The front power rocker switch will not
turn the VS115 off if the remote system is on.
The +12VDC remote jacks have polarity protection, so they
will not operate if a -12VDC signal is accidentally connect-
ed, or if the control wires are reversed. The 12V remote
relay in the VS115 has click suppression to protect circuits