User Manual
darTZeel NHB-108 model one Audiophile's technical manual Page 16 of 28
What about radio waves? What medium
do they use, in the vacuum of inter-
sidereal space? Well, write us, and we
will send you the Physicist manual, as
soon as we have got round to writing it…
As for acoustical waves, it is a much eas-
ier phenomenon to describe, and espe-
cially understand, since it is part of our
daily life.
The medium can be water in the case of
mermaids singing… er, sorry, when
whales sing. Or when more human,
technological things such as sonars,
hydrophones and the like generate and
detect acoustical waves.
The medium can also be steel. The
hammer hitting the string, in a piano,
generates a pulse which creates a
propagating wave in the string, making it
vibrate. Then this vibration will be trans-
mitted into the air.
Air: this is the ultimate medium where
man-made music propagates. Music is
spread in wave form, the latter being
described by a physical law, called "w ave
propagation theory". We will not enter
into the details, but mention just one
crucial and essential point:
Acoustical waves do not move air.
When we read in some high-end maga-
zine that such and such a flagship loud-
speaker can blow out a candle while re-
producing a trumpet or a saxophone,
this is just metaphorical.
The sound is produced by the vibration
of air molecules, step by step. Yes, you
did read correctly. It is vibration, not
movement.
If you know a friend who plays trumpet
or saxophone, just put your hand on the
bell and you will only feel v ibrat io n , not a
single tiny puff of wind. By the way, you
would never think about a piano being
able to stir up air to produce wind, would
you?
These vibrations have a purely single-
ended behavior, since they are produced
around a point of equilibrium, where
vibrations are zero.
To cut a long story short, we can say
that the whole acoustical chain is single-
ended. The only moment when the
acoustical signal could be balanced is
when it travels into the electric wires. In
the air, sound is unbalanced, asymmet-
ric, single-ended, as you prefer.
Why then, this obsession to balance a
naturally unbalanced signal? Is it not
against nature?
Furthermore, where is the real advan-
tage in running the loudspeaker in bal-
anced mode? To our knowledge, there is
no balanced crossover in the market!
Has any manufacturer already told you
that there is no such thing? Okay, now
you’ve been told.
5.4.4. Via the darTZeel
In the version B of the darTZeel NHB-108
model one, we have also installed bal-
anced inputs. Did we do this just in order
to be “with it”?
First, we want to stress that we use
floating balanced inputs. This means that
rather than doubling the whole electron-
ics, as seen above, we use high quality
input transformers. Of course the use of
transformers is much more expensive,
but the resulting performances are far
superior.
Speaking of external disturbance immu-
nity, transformers are much better than
full balanced topology. The common
mode rejection (this is the name given to
that kind of immunity) can be – wait for
it – no less than five thousand times bet-
ter when using transformers instead of
full balanced circuits. Another, unbeat-
able, advantage is that they offer true
electrical isolati on – called galvanic isola-
tion – between the line and the gear,
providing outstanding safety in profes-
sional use. Last but not least is the fact
that all the above-mentioned qualities
are defined at the building stage, mean-
ing that performances will not decrease
over the years or even decades to come.
This is not by any means the case in full
balanced versions.
In conclusion, we cannot resist insisting
on the fact that a full balanced solution
utilizes twice t he number of componen ts,
implying a more complex signal path,
less reliability, and furthermore, espe-
cially in power amplifiers, an output im-
pedance twice as high as with single-