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have measurable resistances, they represent a load where a voltage is
dropped.
So the ground plane is not static but will be modulated with the scraps from the
left + right channel which is a summed mono signal. This can be heard and
measured as crosstalk and intermodulation. The amount is influenced by the
circuitry itself (output impedances), the layout of the amp, the quality of the
headphone cable, the ratio between the sum of the parasitic impedances to the
impedance of the voice coils
… and more.
The better amp is the
balanced amp
or push-pull amp which consists basically
of two amps per channel, one carrying the normal signal, one the inverted
signal.
The load, the voice coil, is now pushed and pulled between the operating
voltages and has nothing to do with the ground potential. So the ground plane
is not polluted by any parasitic influences and the crosstalk is not harmed. Also
the cables of the headphone are clearly assigned:
Two cables to each voice coil with generally resistive loads and only few
complex parts.
The special feature of the combination of a balanced amp with a balanced
headphone is the superb channel separation. I want to state that also the
channel separation of
“normal” headphones and amps is much better than most
program material. So there are not many complaints about
– maybe because
most users don
’t know about the better way…
Sometimes even the high channel separation of normal amps is perceived as
not normal and reduced artificially by
“cross-feed” circuitries.
But the optimized channel separation and low intermodulation are often
responsible for the
“whow” feeling which many first-time listeners have with
balanced headphones.
To say it in a striking manner:
Hearing with loudspeaker is like sitting in the audience, hearing with
headphones is like taking the place of the conductor. Hearing balanced means
being part of the orchestra.
Another technical gain is that you must not use the crappy phone jacks and
sockets no more which partly have dramatic influences on the distortion.
But also the use of 2 x 3-pin XLR connectors seems to be nor very rational.
We from Lake People / Violectric voted for a 4-pin female connector as the
output socket.
