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ical current-to-voltage conversion stage with dedi-
cated operational amplifiers possessing superlative
rise time and bandwidth characteristics.
Following this, an active analog filter circuit,
implemented in a differential amplifier, sums both
halves of the balanced signal and provides superb
common mode noise rejection in addition to
outstanding filtering.
This approach to the DAC circuit block yields
extraordinarily low distortion and noise levels and
contributes greatly to the natural sound of the
Nº390S.
Balanced Analog Volume Control
Rather than use the digital attenuator on board
the DAC, the Nº390S incorporates a fully
balanced analog volume control similar to that
found in Mark Levinson preamplifiers. When acti-
vated, the output of the Nº390S can be
attenuated in precise 0.1dB steps through most of
the range. Significantly, the Nº390S maintains the
full performance of its remarkable DACs at all
volume levels - something impossible with
digital volume controls, regardless of what tech-
niques may be employed to mask the sonic
consequences of that design approach.
State-of-the-Art Output Buffer
The balanced discrete output buffer circuitry used
in the Nº390S employs the same topology used in
the remarkable Mark Levinson Nº32 Reference
Preamplifier. A hallmark of Mark Levinson pream-
plifier and digital processor design, this circuit has
proven to be both sonically transparent and
exceptionally immune to adverse interactions
with interconnecting cables and unusual input
impedance characteristics of power amplifiers or
preamplifiers. The Nº390S features an ultra-
compact implementation of the Mark Levinson
output buffer circuit, pushing noise coupling and
parasitic effects to vanishingly small levels. This
exceptionally robust output stage allows the
Nº390S to make the most of any combination of
preamplifier, power amplifier, and cables used.
Sound Quality
The Nº390S successfully builds on the strengths
of the popular Nº39 CD Processor. The name
change is intended to convey the level of sonic
improvement that can be expected. It doesnt
sound like an improved Nº39 -“ it sounds like a
completely new and significantly better product.
The many design refinements in the Nº390S have
resulted in a significant reduction in the already
very low noise levels present in the Nº39. Low-
level musical details that were previously masked
are now revealed. High-frequency clarity and
extension are improved. Low-frequency detail
and drive is improved. Imaging and spatial infor-
mation are substantially improved, with a greater
sense of depth and width, providing an almost
holographic quality to the presentation.
All of this musical information was always present
on the CDs. Once again, significant sonic
improvements were attained by better implemen-
tation of an existing technology. The Nº390S
acheives that goal.
