Audio Research VS115, Owner'S Manual

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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.
C A U T I O N : The VS115 amplifier contains sufficient levels
of voltage and current to be lethal . Do not tamper with a
component or part inside the unit. Even with the power
turned off, a charge remains in the energy storage capaci-
tors for some time. Refer any needed service to your autho-
rized Audio Research dealer or other qualified technician.
Replacement vacuum tubes may be obtained through your
authorized retailer or directly from Audio Research Cus-
tomer Service. For best performance, the 6550C output
tubes should be matched pairs.
Additional questions regarding the operation, maintenance
or servicing of your amplifier may be referred to Audio
Research Customer Service at (763)-577-9700.
Output Tube Bias Adjustment
As shipped from the factory, the output “bias”
adjustments are set for a nominal 65mA per 6550 tube.
Under these idle conditions the tubes are each dissipating
approximately 27 watts of their 48 watt rating (42
watt plate, 6 watt screen). This point of operation provides
“enriched” Class AB1, and will satisfy the most critical
listener.
For best results, operate and adjust the VS115 at 120VAC.
Adjustment must be made under zero-signal conditions
after at least 15-20 minutes of uninterrupted stabilization
time.
A digital voltmeter capable of accurate measurements with
0.lmVDC resolution is preferred for accurate adjustment
(must have 3
1 /
2
digit display). Use the plastic alignment
tool provided to make the adjustment. The measurement
points are banana test jacks at the rear of the VS115. Ad-
just the “b i as” for an average voltage reading of 65mVDC
(.065 Volt DC) between test jacks.
Cleaning
To maintain the new appearance of this unit, occasionally
wipe the front panel and top cover with a soft, damp (not
wet) cloth to remove dust. A mild, non-alkaline soap solu-
tion or dilute isopropyl alcohol may be used to remove
fingerprints or similar smudges. Cleaners containing abra-
sives should
not
be used as they will damage the anodized
finish of the front panel. A small, soft paint brush is effec-
tive in removing dust from bevels, the recessed nameplate
and other features of the front panel.