Vacuum Tubes and Preparation for Use
Your Reference 110 amplifier is shipped with the vacuum
tubes packed in foam blocks. These must be unpacked and
installed before you attempt to operate the amplifier.
Included are four matched pair of 6550C output tubes, and
four 6H30 dual triodes used in the input stage. Proceed
according to the following instructions.
Carefully remove each vacuum tube from its protective
foam and match its location “V” number (written on the
base of the tube) to the “V” number printed next to each
socket. Firmly seat each tube in its matching socket, taking
care to “key” the tube pins to the socket holes. Retain the
foam blocks with other packing materials for possible
future use. Refasten top cover on amplifier.
Panel Controls
The front panel has:
1 – Switch:
1 - Power line On-Off
1 – Indicator:
1 - Power "On" LED (Green)
Use of Controls
POWER-ON SWITCH
:
Initiates/terminates AC line power
to the amplifier. Function indicated by green LED above
switch.
N o t e :
Audio Research does
n o t
recommend leaving your
Reference 110 “on” 24 hours a day as is the custom of some
audiophiles to achieve maximum sonic performance on de-
mand. While this is often recommended for solid-state
equipment, Audio Research does not recommend this pro-
cedure for vacuum tube power amplifiers. (2,000 hours of
tube life will elapse in 84 days!)
Installation
To insure normal component life and safe operation this
unit
must be operated only in an upright position
.
Adequate air flow and proper cooling can occur only if
there is no restriction above and behind the unit and on
either side. Be sure that airflow to the 12V D. C. cooling
fans located on the rear panel is not blocked.
The special non-marring elastomer feet provide adequate
spacing and stability only on a smooth, hard surface.
F o r
upright stability, never operate the unit while it is sitting
on a soft surface such as a thick rug or carpet.
Due to its weight, this amplifier must be supported on a
surface specifically rated for such a load. Check with the
manufacturer of your support system to be sure it is rated
to handle this weight.
If the unit is to be operated in an enclosure such as an
equipment rack, make certain that adequate air flow above
and to each side of the unit is provided. The “ambient”
operating temperature should never exceed 120º F or 49º C.
Improper 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 prolonged periods, “hot” to the
touch. All components within are, however, operated at
safe, conservative levels and will not be improperly affected
thereby, providing the requirements outlined above are
adhered to.
Connections
INPUT CONNECTOR:
The Reference 110 uses a fully bal-
anced circuit topology and has a pair of balanced XLR
input connectors on the rear panel. It therefore requires a
balanced preamplifier output, as provided by most Audio
Research preamplifiers. Connect your preamplifier's output
to the Reference 110 before turning on the amplifier.
OUTPUT CONNECTORS:
Proprietary, heavy-duty output
terminals are provided on the rear panel for 4, 8,or 16-ohm
speaker impedance loads. Using high-quality speaker
cables, securely fasten the (-) speaker lead to the appropri-
ate (-) terminal, then the (+) lead to the matching (+) termi-
nal. following your speaker manufacturer's impedance spec-
ification. The Reference 110 puts out the same amount of
power whether the 4, 8 or 16-ohm terminals are used.
IMPORTANT:
Use the best available speaker wires and
interconnects. Audio Research cannot emphasize this
enough. As better components and systems are developed,
it becomes increasingly important to avoid the limitations
of inferior system interconnections.
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 Reference 110. Connect
the red or “+” speaker terminal to the wire that connects to
the “4 ” or “8” terminal on the Reference 110. 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 Reference 110 input to the preamplifier or
electronic crossover, using only the highest grade of audio
interconnect cables. To avoid sonic degradation use the
shortest practical length of cables.
Model Reference 110
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