9
Connections
Input Connectors
The Reference 250 SE uses a fully balanced
circuit topology and has a balanced XLR
input connector 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
250 SE before turning on the amplifier.
Output Connectors
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 appropriate (black)
terminal, then the (+) lead to the matching
(red) terminal. Follow your speaker
manufacturer’s impedance specification.
The Reference 250 SE puts out the
same amount of power whether the
4, 8, or 16-ohm terminals are used.
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.
Connect the Reference 250 SE 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.
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 250 SE.
Connect the red or ‘+’ speaker terminal
to the wire that connects to the 4, 8, or
16 ohm terminal on the Reference 250
SE and tighten the speaker terminals
securely to ensure best sonic results.
Summary of Contents for Reference 250 SE
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