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X5 Owner’s Manual
The X5 five channel amplifier embodies the design technology and
refinements of the larger “X” series amplifiers including extensions
of the patented Supersymmetry circuit.
The Supersymmetry circuit topology was granted a U.S. patent in
1994, and is the result of 19 years of effort by Nelson Pass. The
amplifier uses highly matched components in a classically simple
balanced Class A circuit. The amplifier contains only two simple
stages: the first is a balanced single-ended Class A voltage gain stage.
Its output drives a bank of high power Mosfets operated as voltage
followers.
These are inherently low distortion types of circuits, but their
performance is improved when operated in balanced mode through
cancellation. Distortion and noise identical to both halves of a
balanced circuit will disappear at the output, and in a well-matched
symmetric circuit, most of the distortion and noise is identical.
Supersymmetry enhances this effect by providing a connection
between the two halves of the balanced circuit that further perfects
the match. Any distortion and noise not already identical to the two
halves is made identical, and the result is improved cancellation at the
output.
Unlike feedback techniques where the goal is to correct for the
distortion by feeding a gain stage an inversely distorted signal,
Supersymmetry seeks merely to create perfect matching.
Matched balanced power circuitry typically sees a distortion
and noise reduction of about 90% (20 dB) through a balanced
connection without any additional effort. The Supersymmetric
circuit delivers another 90% reduction, so that the X series has
about 1/100 of the distortion of a conventionally simple amplifier.
Actually this ordinary distortion and noise can still be seen at the
output of one half of the circuit, but since it is virtually identical
on the other half, it goes away at the speaker terminals. This gives
good measured performance, which because it is simple, also sounds
excellent.
Previously these kinds of simple Class A circuits have been popular
for their sound quality in low power amplifiers, but have not found
application at high power levels due to excessive distortion and low
efficiency. Supersymmetry overcomes this barrier, delivering the
sweetness, staging, and detail of very simple circuitry up to kilowatt
power levels and beyond.
Introduction
