darTZeel NHB-108 model one
User Manual, version B 1.0
Page
28
of 35
Over longer lengths, external disturbances like
hum, RFI and so forth take on a greater degree of
importance.
The disturbances' intensity can be figured out by
computing the RMS signal to noise ratio, in deci-
bels.
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 balanced 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 50
Ω
links used in the
darTZeel NHB-108
model one
, and described hereunder, behave dif-
ferently…
T5.5. darT
to
Zeel 50
Ω
The
NHB-108 model one
is equipped with 50
Ω
BNC connectors.
After a lot of research, we concluded that the
one
and only
means for transmitting an electrical musi-
cal signal with no alteration 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, especially regarding its cost
price.
We confirm this once again, of course, but the pur-
pose 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
NHB-108 model one
.
As for electric transmission lines, we didn’t want to
reinvent the already existing wheel. Perfect imped-
ance-matched lines have been in use for almost a
century. And so have coaxial cables.
Impedance matched links are utilized everywhere
when high tech performance is needed. Radio ap-
plications, radar, microwaves, computers, and all
such precision technologies use impedance-
matched links. So why not audio?
The great advantage of impedance matched-links is
their virtual absence of losses, whatever their
length.
For those of you who want to know everything
about matching impedance in audio links, do not
hesitate to contact us at
Propagation time delay is preserved in DC up to
several GHz in such lines, and no other link from
any make can claim this, unless perfect impedance
matching is achieved.
So the
NHB-108 model one
is fitted with such
inputs, here called "
Zeel
50
Ω
", while the
darTZeel
NHB-18NS
preamplifier has "50
Ω
darT
" outputs.
These inputs/outputs use 50
Ω
coaxial cables fitted
on BNC connectors.
External disturbance immunity of a coaxial link
depends on the cable itself. It can vary from -50dB
to -100dB or more, the latter being greatly superior
to the full active balanced mode, and all this, please
bear in mind,
without any sonic alteration
.
You can use very affordable off the shelf RG58U
cable, and will be very surprised by the result.
Many shorter but much more expensive cables do
not do better! And when there is a big length in-
crease, there is no shadow of doubt, darT
to
Zeel
50
Ω
is simply unbeatable. Trying and hearing is
just believing.
The optional coaxial cables delivered with the
NHB-108 model one
are furthermore of the high-
end grade, silver plated pure copper, designed for
hyper frequency applications. You will at last dis-
cover what resolution
really
means…
As stated above, one of the main advantages of
darT
to
Zeel
links is that you can locate the power
amplifier as far as you want from the preamplifier.
No more treble roll off, harsh or fuzzy. No more
sluggish low end.
The theoretical length limit is… infinite! In prac-
tice, we recommend not to use lengths greater than
1 kilometre (we are
not
joking here, for once.)
This new way of linking is still in its infancy as
regards audio, even if some of our esteemed com-
petitors disagree.
darTZeel
will also offer in the
near future, for professional applications,
darT
to
Zeel
floating
balanced links.
Are you looking for
darTZeel
sound integrity in
concerts and pro audio studios? You can have it just
for the asking.
