Conrad-Johnson ART
108
A Amplifier Owner’s Manual
8
Getting The Most From Your ART
108
A Amplifier
In a system of commensurate high quality components,
the Conrad-Johnson ART
108
A Amplifier offers an unparalleled
level of sophistication and refinement in music reproduction. To
get the best performance out of any audio system, there are a
number of important details that must be attended to.
Absolute Phase
Musical notes are heard through the ear’s response to waves of
alternating rise and fall of air pressure. Musical transients are
almost exclusively positive: that is, the initial effect is a rise in
pressure. The ear is capable of distinguishing these positive
transients from the musically unnatural alternative of a negative
transient (an initial fall in air pressure). In terms of your stereo
system, these transients are created by your loudspeakers. If the
speakers respond to musical transients by first moving out, they
are creating a rise in pressure, and the system is said to be phase
correct. If they respond by moving in, they create a fall in pressure
and the system is said to be phase inverting. Each component in
the stereo system either preserves the phase of the incoming
signal, and is said to be phase correct, or inverts the phase and is
said to be phase inverting. It is unimportant whether an individual
component is phase correct or phase inverting, as long as the
system as a whole is phase correct. This will be the case if the
number of phase inversions is even (or zero).
The ART
108
A Amplifier is phase correct (non-inverting). If
your system has an odd number of inversions, (for example, if you
have a phase inverting preamplifier) then you must add one
phase inversion. This is conveniently done by reversing the
positive and negative connections to your speakers (be sure to
reverse both channels). If you are not sure about the phase of
every piece in your system, you can establish correct absolute
phase by careful listening. When the system is in correct phase,
transients will be noticeably
cleaner
and
more
sharply
defined. The effect is especially apparent on plucked string
sounds. A final warning - not all re
cordings are phase correct
(including some “audiophile” recordings),
so
listen
to
several
before
concluding
your investigation of absolute
phase.
