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 Reference110 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 yellow and black banana test jacks next to each
output tube. Adjust the “bias” for a voltage reading of
65mVDC (.065 Volt DC) at the blue bias pot for one of each
output tube pair as follows, noting the voltage setting of
the larger V number tube in each pair is slaved to the
adjustment setting of its lower V number companion tube:
Adjust V5 for 65mVDC and measure its companion tube
V7 to verify a reading of 57 to 73mVDC. Repeat procedure
by adjusting and measuring V9 to read 65mVDC and verify
V11 reads 57-73mVDC; adjust and measure V6 to read
65mVDC and verify V8 reads 57-73mVDC, and finally
adjust and measure V10 to read 65mVDC and verify that
V12 reads 57-73 mVDC.
Cooling Fan Speed Adjustment
The two D.C. cooling fans located at the rear of the
Reference 110 are adjustable in speed. Locate the red
colored dip switch under the top cover at the top near the
center of the back panel. For highest fan speed move both
white tabs on the red dip switch to the upward position;
for medium fan speed move either one of the tabs to the
downward position, and for low fan speed move both tabs
to the downward position. For maximum cooling and
extended tube life, use the highest fan speed possible. Be
sure to first turn off and unplug the Reference 110 from
its power receptacle before unscrewing the top cover to
access the switch. Refasten the top cover before resuming
operation. Do not operate the Reference 110 with fans
disconnected or if one or both fans should stop running.
Hour Meter
An LCD hour meter of elapsed tube operating time can be
viewed through the top cover near the front, mounted on
the right main circuit board. Displays accumulated hours of
vacuum-tube service life. If the amplifier is unplugged from
A.C. supply, total accumulated hours are retained. May be
reset by qualified technician. Contact Audio Research Cus-
tomer Service for more information about reset procedure.
Servicing
Because of its careful design and exacting standards
of manufacture, your Reference 110 amplifier should
normally require only minimal service to maintain its high
level of performance.
CAUTION:
The Reference 110 amplifier contains sufficient
levels of voltage and current to be
l e t h a l
. Do not tamper
with a component or part inside the unit. Even with
the power turned off, a charge remains in the energy
storage capacitors for some time. Refer any needed service
to your authorized Audio Research dealer or other
qualified technician.
Additional questions regarding the operation, maintenance
or servicing of your amplifier may be referred to the
Customer Service Department of Audio Research Corpora-
tion at 763-577-9700 ( C ST ). When ordering a service
manual from Audio Research or an authorized dealer, be
sure to identify the serial number on your amplifier.
Cleaning
To maintain the new appearance of this amplifier, occasion-
ally wipe the front panel and top cover with a soft, damp
(not wet) cloth to remove dust. A mild, non-alkaline soap
solution may be used to remove fingerprints or similar
smudges. Cleaners containing abrasives should
not
be used
as they will damage the anodized finish of the front panel.
A small, soft paint brush is effective in removing dust from
bevels, the recessed nameplate and other features of the
front panel.
Disposal and Recycling Guidelines
To dispose of this electronic product, do not place in land-
fill. In accordance with the European Union Waste Electri-
cal and Electronic Equipment (WEEE) directive effective
August 2005, this product may contain regulated materials
which upon disposal require special reuse and recycling
processing.
Please contact your dealer or importing distributor for
instructions on proper disposal of this product in your
country. Or, contact Audio Research Corporation (763-577-
9700) for the name of your importing distributor and how
to contact them.
Packing and shipping materials may be disposed of in a
normal manner.
Model Reference 110
4