DNA-750 Owner’s Manual 4
GETTING THE MOST FROM YOUR DNA-750
In a system of high quality components, the McCormack DNA-750 Power Drive offers a
remarkable 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
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 DNA-750 is phase correct. If your system has an odd number of inversions, (for
example, if you have a phase inverting preamplifier in your system) 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 recordings are phase correct (including some “audiophile”
recordings), so listen to several before concluding your investigation of absolute phase.
The Importance of Wires
Interconnect and speaker wires are an important element in your stereo system.
Interconnects are available which will permit a reference quality system to blossom and
fulfill its promise of musical reality. Others will strangle the system to the point where it
becomes little better than average. To complicate matters, our experience suggests that
the choice of interconnects will be system dependent -those that are top ranked on one
system may be a poor choice for a different system. Consult your McCormack Audio
dealer for recommendations for your specific system.
Performance Tip
Warm up the DNA-750 Power Drive before serious listening: The sonic performance
improves noticeably as the unit warms up. The midrange becomes more lucid, the highs
smoother, and the soundstage expands. The warm up period can be expected to last
about fifteen minutes.
