Nº33H
MONAURAL POWER AMPLIFIER
Each monaural Nº33H weighs in at 175 pounds
(over 80 kg) and takes advantage of a vertically
oriented industrial design that reduces the floor
space the amplifier would otherwise require.
Rated at 150 watts into an 8-ohm-load, the Mark
Levinson Nº33H delivers extraordinary power to
the complex impedances of actual loudspeakers.
Each monaural amplifier chassis employs four
60,000 µF capacitors for a total of almost 1⁄4 Farad
of capacitance. A fully balanced power amplifier
from input to output, the Nº33H optimizes the
reproduction of today's finest sources. It achieves
common mode (noise) rejection in the loudspeak-
er's voice coil, protecting the entire portion of the
signal chain for which it is responsible from radiat-
ed and other forms of common mode noise.
Technical Background
Fully Balanced Power Supply:
The Nº33H uses
two independent, bipolar power supplies to
support the fully balanced nature of the amplifier
from input to output. These are taken from a
single 3.417 kVA custom transformer, using multi-
ple taps to maintain the symmetrical nature of the
two bipolar supplies. Since each amplifier is
monaural, you can count on symmetry at the
transformer for the noninverting and inverting
sides of the same signal. This stands in contrast to
“stereo” amplifiers which share a single trans-
former between dissimilar amplifier channels,
wherein crosstalk through the power supply pres-
ents problems.
AC Regeneration:
One of the most significant
features of the Nº33H amplifiers is the presence of
the AC Regeneration system, which siphons off a
portion of the ± DC power from the main supply,
using it to power an oscillator circuit that gener-
ates pure sine wave AC. Having created this
absolutely clean AC source, we then rectify it,
filter it, and regulate it as you would expect in any
high quality power supply. But because the AC
power we began with was textbook-perfect, the
quality of the resulting ± DC for the sensitive
voltage gain stages is unrivaled. In effect, we
create our own small power utility for the purpos-
es of feeding the power supply of the voltage gain
