Pass Labs X250.5 Manual Do Utilizador
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X250.5 Owners Manual
The Pass Laboratories ™ X250.5 stereo amplifier embodies the de-
sign technology and refinements of the “X” series amplifiers includ-
ing extensions of the patented Supersymmetry™ circuit. Additionally
selected refinements of the XA series amplifiers have been incorpo-
rated into the X250.5 to significantly improve this products sonic
performance in comparison to it’s immediate predecessor, the Pass
Laboratories™ X250.
sign technology and refinements of the “X” series amplifiers includ-
ing extensions of the patented Supersymmetry™ circuit. Additionally
selected refinements of the XA series amplifiers have been incorpo-
rated into the X250.5 to significantly improve this products sonic
performance in comparison to it’s immediate predecessor, the Pass
Laboratories™ X250.
The Supersymmetry™ circuit topology was granted a U.S. patent in
1994, and was the result of 19 years of effort by legendary analog
designer and company founder Nelson Pass. The amplifier uses
highly matched components in a classically simple single ended Class
A circuit. The amplifier contains only two simple stages: the first is a
balanced Class A gain stage. Its output drives a bank of high power
devices operated as followers.
1994, and was the result of 19 years of effort by legendary analog
designer and company founder Nelson Pass. The amplifier uses
highly matched components in a classically simple single ended Class
A circuit. The amplifier contains only two simple stages: the first is a
balanced Class A gain stage. Its output drives a bank of high power
devices operated as followers.
These are inherently low distortion types of circuits, but their perfor-
mance is significantly improved when operated as balanced devices.
Distortion and noise identical to both halves of a balanced circuit can
be made to disappear at the output, and in a well-matched symmetric
circuit, most of the distortion and noise is identical.
mance is significantly improved when operated as balanced devices.
Distortion and noise identical to both halves of a balanced circuit can
be made to disappear at the output, and in a well-matched symmetric
circuit, most of the distortion and noise is identical.
Pass Laboratories Supersymmetry™ enhances this effect by provid-
ing a connection between the two halves of the balanced circuit that
further perfects the match of common mode artifacts. Any distor-
tion and noise not already identical to the two halves is made more
identical by a factor of about 10. The result of this perfected match
is improved noise cancellation at the output of the amplifier. From a
listeners standpoint this results in a more accurate presentation of the
soundstage and better resolution of low level detail.
ing a connection between the two halves of the balanced circuit that
further perfects the match of common mode artifacts. Any distor-
tion and noise not already identical to the two halves is made more
identical by a factor of about 10. The result of this perfected match
is improved noise cancellation at the output of the amplifier. From a
listeners standpoint this results in a more accurate presentation of the
soundstage and better resolution of low level detail.
Unlike feedback techniques where the goal is to correct for the distor-
tion by feeding a gain stage an inversely distorted signal, Supersymme-
try™ seeks merely to create perfect matching between the two halves
of an otherwise well matched circuit.
tion by feeding a gain stage an inversely distorted signal, Supersymme-
try™ seeks merely to create perfect matching between the two halves
of an otherwise well matched circuit.
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 Supersymmetry™ circuit delivers
another 90% reduction, so that the X series has about 1/100 of the
distortion of a conventionally simple and otherwise identical ampli-
fier. 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, these un-
desirable artifacts largely go away at the speaker terminals. This gives
good measured performance, and because a simple circuit produces it,
also sounds quiet excellent.
reduction of about 90% (20 dB) through a balanced connection
without any additional effort. The Supersymmetry™ circuit delivers
another 90% reduction, so that the X series has about 1/100 of the
distortion of a conventionally simple and otherwise identical ampli-
fier. 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, these un-
desirable artifacts largely go away at the speaker terminals. This gives
good measured performance, and because a simple circuit produces it,
also sounds quiet excellent.
Introduction