9
Input Connectors
The VT80 uses a fully balanced circuit
topology and has a pair of balanced XLR
input connectors along with a pair of single-
ended RCA input connectors. The rear panel
switch must be in the appropriate position
for either Single-Ended or Balanced use.
Connect your preamplifier’s output to the
VT80 before turning on the amplifier. Do not
connect the balanced XLR input connectors
and the single-ended RCA connectors at the
same time – connect one pair or the other.
Output Connectors
Proprietary, heavy-duty output terminals
are provided on the rear panel for 4 or
8-ohm speaker impedance loads. Using
high-quality speaker cables, securely fasten
the (-) speaker lead to the appropriate
( 0 Ω black banded) terminal, then the
(+) lead to the matching (4 or 8 Ω red
banded) terminal. Follow your speaker
manufacturer’s impedance specification.
The VT80 puts out the same amount of
power whether the 4 or 8-ohm terminals
are used.
Note:
The 4 Ω tap is grounded. Avoid
wiring and speaker switching systems that
have a common ground wiring or switching
of the amplifier output. Some headphone
switching systems have a common ground.
Special connections must be made to use
such systems. Contact Audio Research
customer support for more information.
Connections
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 VT80. Connect the red or ‘+’ speaker
terminal to the wire that connects to the
‘4’ or ‘8’ terminal on the VT80 and tighten
the speaker terminals securely to ensure
best sonic results. Use a 7/16” (12mm)
hex- end screwdriver to tighten the output
terminals. Avoid using a wrench as this can
lead to overtightened, stripped or broken
output terminals.
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 spectrum, such
as most electrostatic types, determine the
best impedance match empirically for best
overall sonic results.