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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

Summary of Contents for Reference 110

Page 1: ...3900 ANNAPOLIS LANE NORTH PLYMOUTH MINNESOTA 55447 5447 PHONE 763 577 9700 FAX 763 577 0323 Model Reference 110 STEREO POWER AMPLIFIER Owner s Manual...

Page 2: ...Preparation for Use 2 Panel Controls 2 Use of Controls 2 Installation 2 Connections 2 3 Remote Turn on Connections 3 Operating Procedure 3 Output Tube Bias Adjustment 4 Cooling Fan Speed Adjustment 4...

Page 3: ...S WHICH MAY BE HAZARDOUS REFERENCE 110 S T E R E O A M P L I F I E R VOLTS SERIAL PLYMOUTH MINNESOTA CAUTION FOR CONTINUED PROTECTION AGAINST FIRE HAZARD REPLACE FUSE ONLY WITH SAME TYPE AND RATING WA...

Page 4: ...The 12 gauge 3 conductor detachable power cord on your Reference 110 is equipped with a standard 3 prong grounding plug If used normally it will provide a safe earth ground connection of the chassis R...

Page 5: ...r installation will cause premature tube failure and will affect your warranty as well as the service life of the unit It is normal for a vacuum tube power amplifier to run quite warm and if used for...

Page 6: ...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 Always place the power on off switch on...

Page 7: ...ld 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 vac...

Page 8: ...encountered and any information necessary for return shipment The cost of return shipment is the responsibility of the purchaser Specifications POWER OUTPUT 110 watts per channel continuous from 20Hz...

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