Audio Research Reference 210 Owner's Manual - Model Reference 210
electronics technician.
3. Use only the plastic insulated screwdriver included with
this unit when making front panel bias adjustments.
4. The power cord on this unit is safety-tested and is
equipped with a proper grounding plug. If used normally,
it will provide a safe earth ground connection of the
chassis. Defeat of the grounding plug, or any unautho-
rized modification of the active circuitry or controls of
this unit, automatically voids warranty coverage,
5. For safe operation and protection against fire hazard,
replace fuses only with those of the same type and
rating as those supplied with this unit.
6. At 74 lbs. net weight per chassis, the Reference 210
amplifier is too heavy for one person to lift. To avoid
injury, do not attempt to unpack, lift or move the unit
without the help of at least one other person.
7. Always mute the preamplifier when cueing a phono
cartridge stylus up or down.
Due to the immense power supply reserves, high power
output, and wide bandwidth of the Reference 210, added
emphasis must be placed on use of your preamplifier's
mute switch from a safety standpoint. A transient signal
burst or “pop” such as caused by tonearm cueing, acci-
dental dropping or brushing of the phono cartridge
s t y l us–even at a normal listening level –could cause an
instantaneous peak power demand on the amplifier of
up to 1000 watts (which the Reference 210 will try to
deliver). The importance of lowering the preamplifier
volume level to a minimum setting and activating the
mute switch whenever cueing the tonearm or making
contact with the phono cartridge stylus cannot be over-
emphasized. Adhering to this precautionary muting pro-
cedure is equally important when turning your system
on or off, and when connecting or disconnecting any
cables in the system. Carefully following this recommen-
dation will minimize the chance of causing undue stress
and potential damage to your amplifiers and loudspeak-
ers. (See your preamplifier Owner's Manual for more
detailed instructions on use of muting provisions.)
Description of Controls
Front Panel Control
POWER: This switch turns the amplifier on and off. When
turned on, there is an automatic warm-up sequence for ap-
proximately two minutes, during which “Mute” will flash in
the display window. After this initial warm-up the amplifi-
er is ready for listening. The display screen will default to
the “Power Output” scale chosen previously. If turned off
and then on again, the amplifier will repeat the2-minute
slow-start cycle. We recommend that the Reference 210 be
switched to “Off” when there are protracted intervals
between listening sessions.
Display Screen
The screen displays all functions and operating modes as
they are selected. Power Output bar graph as normal
default in Operating Mode; large numerals for A. C. line
voltage; large numerals for bias check; and small numerals
for total hours accumulated. Note that the “Hours” function
will turn off after ten seconds.
In the event of low-A. C. line conditions while in “Operate”,
the amplifier automatically mutes the output and the
screen displays “Mute” and “Low Line.” (This also occurs for
3 seconds at turn-on.) When sufficient A.C. supply
resumes, the amplifier will enter its normal two-minute
warm-up cycle.
Handheld Remote Control Functions
All display functions of the Reference 210 must be
addressed by pressing buttons on the handheld remote
control. Note that power on/off can only be selected by
using the front-panel switch or via the 12V trigger.
INTENSITY: Adjusts level of display screen illumination to
any of seven levels including full off.
H O U R S : Displays accumulated hours of vacuum-tube
service life, up to 500,000 hours. If the amplifier is
unplugged from A.C. supply, total accumulated hours are
retained. May be reset by qualified technician. Contact
Audio Research Customer Service for more information
about reset procedure.
POWER SCALE DOWN/UP: Selects and displays power
output scale via moving logarithmic bar graph: 0-10 watts,
0-50 watts, 0-100 watts, 0-200 watts, The normal default
display mode when the amplifier is in Operate.
READ BIAS V1–V6 DOWN/UP: Displays bias level of each
output tube in mA. When selected, V1 or V2 may be
adjusted by inserting the supplied flat-bladed tool into the
respective adjustment pot on the front panel and rotating
until “65 mA” appears in the display. All other tube
locations (V3–V6) may only be checked for bias level, not
adjusted. They should normally display a bias value
between 57 and 73 mA. Note that amplifier is muted in
this mode. Please read “Bias Adjustment Procedure”
on page 3
DISPLAY FUNCTION DOWN/UP: Selects desired display
function from options listed above, also including
Model Reference 210
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