Mark Levinson 434 Owner's Manual page 8

Getting Started Mark Levinson
Special Design Features (continued)
True Voltage Source
The Nº436/434 operates as a true voltage source, maintaining the
appropriate voltage within its rated voltage output according to
the demands of the source material rather than the current
demands of the loudspeaker. As a result, the Nº436/434 doubles its
power output each time loudspeaker impedance is cut in half. For
example, the Nº436 offers rated power at 350W per channel at 8Ω
and 700W per channel at 4Ω.
To control the flow of its remarkable power capabilities to the
loudspeakers, the Nº436 uses 16 TO-3P output transistors in eight
matched, complementary pairs per channel. Similarly, the Nº434
uses eight TO-3P output transistors in four matched, complemen-
tary pairs per channel.
Although most loudspeakers cannot absorb the continuous full
power capabilities of the Nº436, many high-quality loudspeakers
require extreme short-term power levels when reproducing music
at realistic levels. The Nº436/434 can meet these demands without
power supply "sag" or sonic performance alterations, allowing
either power amplifier to reproduce music with amazing authority
and control. Power needs depend on listening habits, the listening
room, and associated loudspeakers.
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Adaptive Bias
The Nº436/434 uses a proprietary adaptive biasing scheme to
deliver the advantages of a Class A output stage without the asso-
ciated thermal management problems and sonic compromises.
This unique adaptive biasing scheme does not allow output
devices to be reverse-biased, replacing dynamic distortions with a
sweeter sound that provides a greater sense of ease regardless of
volume level. Contact an authorized Mark Levinson dealer for
additional information about Adaptive Bias.
Extensive Protection
Designed to prevent damage to itself and associated components,
the Nº436/434 is armed with several protective features. For
example, the AC input to each transformer is fused to protect
against excessive current conditions that occur when shorted
outputs are driven. Inrush limiting prevents premature aging of
power supply components during power cycles, switching off-line
once the power supply is charged. And, a controlled-clipping
circuit prevents output devices from saturating, using wave-shaping
action to avoid the harsh, high-frequency harmonics generated by
hard-clipped output devices.