darTZeel Audio NHB-108 - Manual (Page 17)

darTZeel NHB-108 model one Audiophile's technical manual Page 17 of 28
ended topology, and requires a higher
output stage NFB to compensate.
Now that you have read these simple but
demonstrative explanations, do the
words "full balanced" still mean "abso-
lute superior sound" for you?
All this explains our choice for using, as
a matter of course, transformers of the
highest quality for our XLR inputs in the
version B.
We said above that by very nature, mu-
sic is part of a single-end world. More
than 100 years ago, designers chose
floating balanced lines – full balanced
was not ready yet – for long distance
links for the sole purpose of minimizing
external disturbances.
Electric signals were therefore transmit-
ted in a balanced way, the equipment
working in single-ended mode.
The darTZeel NHB-108 model one version B
offers this very same possibility to pro-
fessional users wanting to link their re-
mote consoles to the NHB-108 model
one, without having to use poor quality
Balun-DI devices.
Despite what all our esteemed competi-
tors might think, we assert and corrobo-
rate that the one and only means of
processing, amplifying and broadcasting
a musical signal without altering it, even
in the slightest, is simply to use the sin-
gle-ended mode.
But only in a special way, though…
With short cables, say less than 10 me-
ters, symmetrical - balanced - transmis-
sion does not have any justification but
marketing. A given gear "singing" better
in balanced mode only reveals poor de-
sign in some part of the circuit, which
can be partially masked by internal dis-
turbance cancellation.
Over longer lengths, external distur-
bances like hum, RFI and so forth take
on a greater degree of importance.
The disturbances' intensity can be fig-
ured out by computing the RMS signal to
noise ratio, in decibels.
A balanced, high quality, floating line can
reach more than 120 dB of rejection,
or -120dB relative to the signal, which
represents one part per million, 1 ppm, a
truly remarkable performance.
In full balanced mode, the result is far
inferior, and in practice is barely better
than -60dB, 0.1%. This may seem small,
but just keep in mind that this implies
component tolerances tighter than 0.5%,
a truly demanding task. Professional
consoles capable of such results are truly
high-end by their 6+ figures price.
It is very important to point out that bal-
anced lines, whatever they may be, are
not impedance matched. This means
that even though they are fairly immune
to external disturbances, they alter the
musical signal proportionally to their
length.
Just ask a sound engineer if he is happy
to use a cable 100 meters long when 10
meters are plenty enough.
Just ask him if high frequencies do not
suffer from very great lengths, of the
order of 100+ meters.
The 50Ω links used in the darTZeel NHB-
108 model one, and described hereunder,
behave differently…
5.5. darT to Zeel 50Ω
The darTZeel NHB-108 model one is
equipped with 50Ω BNC connectors.
After a lot of research, we concluded that
the one and only means for transmitting
an electrical musical signal with no al-
teration or losses over a long distance is
impedance matched lines, from end to
end.
We have already mentioned that the
darTZeel NHB-108 model one was thought
up without any compromise in mind, es-
pecially regarding its cost price.
We confirm this once again, of course,
but the purpose here is just to say we
pursued this quest of sound purity
simply because no other amplifier could
bring us what we were looking for. So we
designed the darTZeel NHB-108 model one.
As for electric transmission lines, we
didn’t want to reinvent the already exist-
ing wheel. Perfect impedance-matched
lines have been in use for almost a cen-
tury. And so have coaxial cables.
Impedance matched links are utilized
everywhere when high tech performance
is needed. Radio applications, radar, mi-
crowaves, computers, and all such preci-