Pass Labs X1000 - Manual (Page 2)

Page 2
Now For Something Completely Different:
The X Series are the biggest and most powerful amplifiers we have created, but they are not
unique for that reason. We have chosen the biggest and most powerful as the proper temple
for a new concept in high performance audio amplification.
Called Supersymmetry™, the circuit topology was granted a U.S. patent in 1994, and is the
result of 19 years of effort by 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 without feedback.
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.
The X Series amplifiers have the tremendous dynamic range (>150 dB) to do justice to the 24
bit recordings of the 21
st
Century. The simple but powerful circuitry moves easily from total
silence to explosive transient and back to silence without a trace. It’s a spooky experience.
Because these amplifiers do not rely on output feedback for high performance, their
performance is consistent across the audio band, from DC to beyond audibility. They are
unconditionally stable into any loudspeaker.
If you need even more power, X1000’s can be operated in series and parallel arrays. As a
practical matter, we offer peak output levels to 64,000 watts.
So relax and enjoy your amplifier. Call us if you ever have a problem or question.