Mark Levinson N 320S User Manual
N
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320S
PREAMPLIFIER
The Nº320S Preamplifier is a direct descendant of
the critically acclaimed Nº32 Reference
Preamplifier. The Nº320S features audio circuits,
controls, architecture, and phono input option
based on the Nº32. In fact, some audio circuits,
such as the proprietary discrete volume attenuators, are identical to those found in the Nº32.
The single-chassis design of the Nº320S achieves
similar separation of audio circuit, control, and
power supply sections as the dual-chassis Nº32.
Inside the Nº320S, these sections are separated
by physical layout as well as a steel shield box
that protects against electrostatic and magnetic
interference. Filtered AC power is routed outside
audio circuit sections, providing audio circuits
with the quiet, shielded environment essential for
superior sound.
Many high-performance audio components rely
on clean, noise-free AC power to deliver
maximum performance. Unfortunately, most AC
power does not meet these standards. Common
household appliances such as refrigerators, televisions, and computers often contaminate AC
power lines with line noise, spikes, and other
irregularities that make it difficult for highperformance audio circuits to reach their full
potential.
To compensate for this, the Nº320S offers a series
of highly effective noise suppression and isolation
technologies. AC power is filtered for noise as
soon as it enters the chassis. The audio section
and control section have completely independent
power supplies, each with their own low-noise
toroid transformers. The audio power transformer
features a Faraday shield between the AC line
and the low voltage secondaries for improved
isolation. The Nº320S employs two stages of
active voltage regulation for the audio sections. A
high-power stage absorbs line voltage and temperature variations, while a second
high-performance stage provides local, highspeed, low-noise power for the audio section.
Featuring an advanced dual-mono design, the
Nº320S is endowed with remarkable channel
separation and exceptional sonic imaging. Both
audio channels use independent power supplies,
communication circuits, and audio circuits. In
addition, each channel’s audio circuits are located
in a separate area of the chassis. This innovative
design isolates each channel from the other,
allowing the Nº320S to produce vividly rich,
three-dimensional sonic images with stunning
precision.
For even greater channel isolation, the Nº320S
deactivates unused inputs to prevent interference
from associated components. When an input is
deactivated, the Nº320S disconnects the input
signal and ground connection, eliminating ground
loop noise between the Nº320S and the associated component. As a result, input signals pass
through the Nº320S with exceptional freedom
from interference due to other components.
Two Mark Levinson-designed discrete volume
attenuator modules control master volume level
with unparalleled accuracy and sonic neutrality.
Constructed with Arlon 25N circuit boards with
local power supply regulation and bypass capacitors, these modules generate optimal power and
isolation for even the most sensitive adjustments.
Precision surface-mounted resistors accommodate
adjustments in 1.0dB increments up to 23.0dB
and 0.1dB increments above 23.0dB.
Unlike other stereo preamplifiers, the Nº320S is
designed to integrate with multi-channel
surround sound processors – minus the drawback
N
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320S
PREAMPLIFIER
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