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It’s All About Balance
The Science of Balance
Headphones share a common connection on the non-driven side of the driver
elements. You can see this by looking at a headphone plug; the left channel
connection is at the tip, the right channel connection is the ring, and the com-
mon connection were talking about is the remainder of the plug shaft, called
the sleeve. The problem is that the summed left and right channel return cur-
rent will develop a signal across the series resistance of the common return
path, which muddies the stereo presentation on headphones with cross-talk.
It is this headphone connector found on all headphones that makes it impos-
sible to drive the return side of the headphone coils with the separate left and
right inverted signals of a fully balanced amplifier. HeadRoom has overcome
this problem with the Balanced Home and Balanced Max Headphone Ampli-
fiers, along with Cardas custom headphone cables.
Driving headphones in balanced mode effectively delivers twice the slew rate,
half the amplifier output impedance, and rids the headphones of significant
cross talk due to the common return connection from the drivers. It really is
another headphone listening experience.
For you scientifically inclined folks out there, here’s the techspeak about bal-
anced amps: Any time an electrical signal passes through a cable, outside
(electrical) noise interference can be induced, even when using shielded ca-
bles. In an unbalanced system, both the positive and negative halves of the
waveform travel together down the positive and negative signal leads and can
be influenced by the outside noise. In a balanced system, the positive and
negative halves of the waveform are separate; when these separate halves
pickup the same outside electrical noise interference, the noise components
on one half are out-of-phase with the noise components on the other half (al-
most like a mirror image). When the negative and positive halves of the signal
are combined in the balanced amplifier, the out-of-phase noise components
on the two halves cancel each other out as they are combined, leaving only
the original, clean output signal... Translation: superb sound!
How about another helpful feature: The Balanced Home amp can double as a
very superb sounding, fully balanced preamp. Make sure the Processor and
Filter switches are in the OFF position when listening through speakers to
avoid goofing up your imaging and frequency response. Because the Home is
a fully balanced unit, it is a good idea to study the details of how to hook up
the Home to your source or call us if you have further questions.
Ground wire resistance of common signal return develops
inter-channel cross-talk distortion
All driver terminals driven with discrete signals.
No common signal paths to muddy audio
Using the Balanced Home as a PreAmp
