darTZeel Audio NHB-108 - Manual (Page 18)

darTZeel NHB-108 model one Audiophile's technical manual Page 18 of 28
sion technologies use impedance-
matched links. So why not audio?
The great advantage of impedance mat-
ched-links is their virtual absence of
losses, whatever their length.
For those of you who want to know eve-
rything about matching impedance in
audio links, do not hesitate to contact us
at
[email protected]
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 darTZeel NHB-108 model one is fit-
ted with such inputs, here called "Zeel
50Ω", while the darTZeel preamplifier has
"50Ω darT" outputs.
These inputs/outputs use 50Ω coaxial
cables fitted on BNC connectors.
External disturbance immunity of a coax-
ial link depends on the cable itself. It can
vary from -50dB to -100dB or more, the
latter being greatly superior to the full
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 increase,
there is no shadow of doubt, darT to Zeel
50
Ω is simply unbeatable. Trying and
hearing is just believing.
The optional coaxial cable delivered with
the darTZeel NHB-108 model one is fur-
thermore of the high-end grade, silver
plated pure copper, designed for hyper
frequency applications. You will at least
discover what resolution really means…
As stated above, one of the main advan-
tages 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 practice, we recommend not to use
lengths greater than 10 kilometers (we
are not joking here, for once.)
This new way of linking is still in its in-
fancy as regards audio, even if some of
our esteemed competitors 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.
6. Onboard safety
A power amplifier like the darTZeel NHB-
108 model one cannot but offer the high-
est quality level when it comes to moni-
toring and protection.
Purity.
But we did not call this part of the darT-
Zeel NHB-108 model one the "protection
circuit", by far preferring "supervision
system", or "monitoring circuit", as you
prefer. Indeed, this very sophisticated
module is kept totally outside the signal
path, electrically and physically, again so
as not to disturb the delicate musical
message.
Reliability.
The supervision system is based on a
100% analog design, making it inde-
pendent from any problem or bug com-
ing from a microprocessor.
The vital passive components have been
selected for their extremely long life,
greater than 40 years in continuous use.
Your loudspeakers – and yourself – can
rest on both ears, for quite a while.
6.1. Crowbar circuit
You will have read this odd name several
times in the Owner's manual, maybe
without having a clue about what it
really is.
This circuit has been well known for dec-
ades in industrial power electronics. By
power electronics, we mean powers
ranging from 50 to 200 kilowatts, like in
on-line inverters used for mainframe
computers or in hospital surgery "white"
rooms.
On these powerful machines it is not al-
ways easy to suddenly cut off the power
supply without causing electrical dam-
age. Inductive loads can release huge
energy transients which need to be
properly directed.