Input Connections Warning; Single-Ended Operation; Balanced Operation; Remote Turn-On Connections - Audio Research VS115 Owner's Manual

Model VS115
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
in the master control system.

Operating Procedure

1. Make sure you have read and complied with the IN-
STALLATION AND CONNECTION instructions prior to
attempting operation.
2. Make sure your VS115 is properly connected to a high-
current power receptacle via the attached power cord
(see AC POWER CONNECTIONS).
3. Your preamplifier should be "on" and muted and/or set at
minimum gain.
4. Turn the Power switch from "Off " to "On." The green
power LED indicator should glow immediately. Note: If
the power indicator LED fails to light, turn the Power
switch to "Off" and check the appropriate fuse for possi-
ble failure.An extra fuse for A.C. power is included with
your VS115.
5. Your VS115 should now operate satisfactorily. However,
a full stabilization or warm-up time of approximately one
hour is recommended for best sonic performance.

Servicing

Because of its careful design and exacting standards of
manufacture, your VS115 amplifier should normally require
only minimal service to maintain its high level of perfor-
mance.
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