darTZeel NHB-18NS User manual

NHB-18NS preamplifier
User Manual
(Pre-release)

darTZeel NHB-18NS User Manual, version 0.93 Page 2 of 10

darTZeel NHB-18NS User Manual, version 0.93 Page 3 of 10
Table of contents
1. Introduction .......................................................................................................4
2. Brief description................................................................................................4
3. The NHB-18NS in details...................................................................................5
3.1. FRONT PANEL..........................................................................................................5
3.2. REAR PANEL ............................................................................................................5
3.3. Connecting the NHB-18NS.................................................................................6
3.4. Using the NHB-18NS..................................................................................................6
3.5. Special features ...........................................................................................................7
3.6. LED Status ..................................................................................................................8
3.7. Remote control............................................................................................................8
4. Technical data (subject to change)......................................................................9
5. Phono settings....................................................................................................10

darTZeel NHB-18NS User Manual, version 0.93 Page 4 of 10
darTZeel NHB-18NS
User Manual
1. Introduction
Congratulations for purchasing a darTZeel NHB-18NS.
Our machines are designed and hand built for very
long lasting use and musical pleasure.
The darTZeel NHB-18NS is a highly unusual
preamplifier, and requires special care. We strongly
recommend you read this manual in its entirety, in
order not to miss any reason for enjoying your ma-
chine at its very best!
In order to facilitate packing/unpacking operation,
please go to our web site www.darTZeel.com and
download our full pictured packaging instruction.
2. Brief description
The darTZeel NHB-18NS is the perfect partner of
the NHB-108 model one.
The in-house designed, built-in phono stage, is
offered as a standard feature.
One of the secrets of the darTZeel NHB-18NS can
be found in two words:
Passion and Love… The passion for sound, of
course, and love of music, needless to say…
As for the rest, we just put in few electronics, a wee
bit of mechanics, and a touch of appropriate soft-
ware.
The NHB-18NS is a full battery powered machine.
Two different operation modes can be chosen:
1. Automatic mode:
Every time you will switch your preamplifier
ON, battery operation mode will be selected,
no matter if the batteries are fully charged or
not. In case batteries would need a charge, or
when the NHB-18NS is switched off, the ex-
ternal supply will charge them automatically.
When batteries are fully charged, you can ex-
pect for a battery life of about 12 hours.
2. BTM (AC mode):
In this mode, batteries will be constantly kept
fully charged. A built-in overcharge protection
allows for using this mode permanently, ensuring
you will benefit of a full charge when you will
perform some critical listening session.
More detail about these two modes are described
later (Chapter 3.5 Special features).
As for the embarked technology, the NHB-18NS is
truly at the peak that is possible to realise today.
With more than 1,200 electronic parts involved, we
however kept our very first aims untouched. The
signal path only travels through 7 junctions (7 tran-
sistors) from input to output, while the phono stage
only adds 6 junctions for the sake of best transpar-
ency.
All basic circuits – phono stage included – are
directly derived from the internationally patented
NHB-108 model one amplifier’s. No global feed-
back, open loop output stages, very wide bandwidth
and extremely low phase shift: this is the NHB-
18NS.
Our proprietary volume control involves a very new
approach, never achieved before: no any contacts,
relays, switches or silicon devices are used. The
delicate sound then remains untouched, for your
greatest pleasure, so the reason why we did not
write “Volume” on the front plate, but simply
Pleasure Control… The way we do it is still a bit
confidential at the moment; we just can say that
some light is involved in the control.
The Enjoyment Source – commonly called “input
selector” – also benefits from the very same kind of
approach: we do not select the input, we do enable
it. Here again, no switch, relay or the like.
NS stands for No Switch. We are very proud that
the NHB-18NS is the very first “zero contact”
preamplifier in the world. So we are even prouder
you can enjoy it right now.
This present user manual is still under its prelimi-
nary state, so please excuse us for some missing
detailed explanations and less than perfect presenta-
tion…

darTZeel NHB-18NS User Manual, version 0.93 Page 5 of 10
3. The NHB-18NS in details
3.1. FRONT PANEL
1. Power Nose 5. Mute / HT Bypass
2. Enjoyment Source 6. Mono-Stereo / Dimmer
3. Pleasure Control 7. Identity Plate
4. Balance Control
3.2. REAR PANEL
1. Phono Input 6. Line RCA Output
2. Line RCA / Zeel Input 7. Line darT Outputs
3. Line RCA / Zeel Inputs 8. Line RCA Fixed Output
4. Line XLR Input 9. Power Supply / Trigger Outputs
5. Line XLR Output

darTZeel NHB-18NS User Manual, version 0.93 Page 6 of 10
3.3. Connecting the NHB-18NS
First connect the external power supply’s umbilical
cord to the power connector located on the Rear
Panel (Chapter 3.2. fig 9).
Then connect the AC cord into your wall socket.
Phono input:
Use inputs I (Chapter 3.2. pos. 1). You can either
connect the ground wire to left or right channel.
The toggle switch allows choosing phono ground
path between signal ground, AC earth, or floating.
Default position is Gnd (right). If you hear some
abnormal rumble, you can play with both channels’
toggles in order to minimize it.
Phono settings: You can change the phono input
settings by a wide margin, allowing for most MM
and MC cartridges. This can be done using a solder
iron. This will be explained in details in the final
manual release. Factory settings are:
MC, gain = 60 dB, load = 836 ohms
This setting works well for most audiophile car-
tridges with an output level from 0.3 to 1 mV.
Line inputs:
Inputs II to V (Chapter 3.2. pos. 2 & 3) are for
RCA single ended sources, input VI is for XLR true
balanced sources.
Toggle switches:
For inputs II to V, default position is center. Left
position provides 6 dB of attenuation in the case
your source would exhibit a very high output level.
Right position is for Zeel 50-ohm purpose, dedi-
cated to future darTZeel sources.
For input VI (Chapter 3.2. pos. 4), the upper tog-
gle default position is center. Right position offers
600-ohm input impedance for professional gear.
Left position lowers the gain by 6 dB; this attenua-
tion only works when true floating source is used
(transformer output source).
Lower toggle switch allows for various ground path
schemes regarding the XLR chassis jack. Default
position is right. Center position is floating, useful
in certain circumstances for cancelling ground
loops. Left position is with XLR chassis connected
to ground via a 100-ohm resistor, for same purpose
as described for center position.
Outputs:
Nothing particular to notice here, save the following:
REC output (Chapter 3.2. pos. 8) is a fixed, buff-
ered output. Loading it with a matching component
like a recorder or a CD burner will therefore not
affect the sound quality. Due to non use of any
global negative feedback, the output gain is slightly
lower than 0 dB.
BNC darT outputs (Chapter 3.2. pos. 7): All these
3 output are separately buffered, and are dedicated
for feeding the darTZeel NHB-108 model one
power amplifier. Optional, built-in filters can be
activated for bi-amping or tri-amping purpose.
This special feature will be explained in details in
the final manual release.
3.4. Using the NHB-18NS
Once everything has been properly connected, you
can power the preamplifier ON by pressing the
Power Nose (Chapter 3.1. pos. 1).
After about 10 seconds, the NHB-18NS is ready to
play music.
When “enjoying” from a line source to another one,
about half a second dead-time is allowed for block-
ing bumps and clicks.
When “enjoying” from line to phono, a very small
click can be heard (independent of pleasure control
position), then the phono stage is activated after
around 8 seconds.
When going back from phono to line, only half a
second is required.
Balance control (Chapter 3.1. pos. 4):
This is not a standard balance control (of course, it
is a darTZeel machine)!
When using the Balance, the change only begins
after about plus and minus 5 degrees of rotation,
ensuring that when you are close to middle posi-
tion, balance channel is kept dead center.
At full right position, R channel is increased by 3.5
dB, L channel lowered by 3.5 dB.
At full Left position, L channel is increased by 3.5
dB, R channel lowered by 3.5 dB.
This feature allows for very fine adjustment, and
keeps global loudness at same level even while
altering the balance control from central position.

darTZeel NHB-18NS User Manual, version 0.93 Page 7 of 10
3.5. Special features
Home Theater Bypass:
If you hold the mute toggle switch (Chapter 3.1. pos. 5) for about 7 seconds, the Mute LED will go green, indi-
cating that the corresponding input is now in HT bypass mode. The pleasure control is now defeated, and the
global In-to-Out gain is set at 0 dB. The setting will be kept in memory until the Mute toggle will be hold again
for 7 seconds.
Each input can be HT bypassed separately if needed.
Front panel Illumination
You can switch off - or back on - all light illumination (LEDs and knobs surrounding) by either doing the followings:
Holding down the Mono/Stereo toggle switch (Chapter 3.1. pos. 6) for 3 seconds.
OR
Pressing, on the remote control, both plus and minus loudness keys for about 2 seconds.
Power supply mode operation
From software version 2.10, it is now possible to choose between two operating modes:
1. BTM (Battery Through Mode, or so called AC Mode): batteries are always kept under charge/maintain
mode, whatever the NHB-18NS is switched on or off. This new factory default mode allows for ex-
tended battery life time and ensures batteries will be fully charged while performing critical listening
session. In this mode, power is supplied by the external power supply through internal batteries, exactly
like a computer in-line UPS (Uninterruptible Power Supply): AC grunge, while not fully removed, will
be well filtered out thanks to batteries’ damping action. This mode will also permit the NHB-18NS to
operate even if batteries do not hold a charge anymore, allowing for smooth operation until eventual
batteries’ replacement.
2. Automatic Mode: the NHB-18NS always works on battery mode when powered on, as long as they
have enough juice. Batteries are charged/maintained when the machine is switched off. This is the mode
you will choose when performing critical listening session, when you will want to be sure there are no
any noise and/or RFI coming from AC mains.
Ultimate sound performance will be given in Automatic Mode.
In case of intensive use, say more than 4-5 hours every day, we strongly recommend switching to BTM for about
2-3 days every month: this will allow for full reconditioning charge and will ensure longest possible life span of
batteries.
!!! NEVER, EVER PHYSICALLY REMOVE OR UNPLUG BATTERIES !!!
THE NHB-18NS WILL NOT START UP DOING THIS
Going from BTM to Automatic Mode:
•Press down both "Mono/Stereo" and "Mute" switches for 2 seconds.
•Central LED colour status will change from GREEN to ORANGE.
Going from Automatic Mode to BTM:
•Press down both "Mono/Stereo" and "Mute" switches for 2 seconds.
•Central LED colour status will change from ORANGE to GREEN.
LED status has been updated too, in order to provide you a better monitoring view of the chosen operation mode.
Please read very next chapter, which explains this in detail.

darTZeel NHB-18NS User Manual, version 0.93 Page 8 of 10
3.6. LED Status
The 3 LEDs inform you about almost everything you would need to know. In order to better understand their
behaviour, hereunder is a summary:
Central power LED in BTM:
NHB-18NS powered ON ÆGREEN = BTM or remote receiving NO LIGHT = mains failure
NHB-18NS Powered OFF ÆRED = Permanent charge / maintain
NHB-18NS Powered OFF, when an AC mains failure occurred: NO LIGHT
Central power LED in Automatic Mode:
NHB-18NS powered ON ÆORANGE = battery mode RED = charging GREEN = remote receiving
NHB-18NS Powered OFF ÆORANGE = charging GREEN = 85% charged / maintain
NHB-18NS Powered OFF, when an AC mains failure occurred: NO LIGHT
Mute LED:
NHB-18NS powered ON ÆORANGE = normal mode RED = Mute GREEN = HT bypass
NHB-18NS Powered OFF ÆNO LIGHT
Mono/Stereo LED:
NHB-18NS powered ON ÆORANGE = stereo mode RED = mono mode
NHB-18NS Powered OFF ÆNO LIGHT
3.7. Remote control
Every time you either press plus or minus loudness key(s), all three LEDs are going GREEN until you release
the pressure. So you perfectly know when the NHB-18NS receives an order. This feature is very useful when
you want to adjust the loudness in very small increments.
Functions:
•Briefly hitting - pulse hit - plus or minus key: Level increases or decreases by 0.5 dB
•Holding plus or minus key: Level change speeds up to 5 dB per second (time dependent speed).
•Pressing both plus and minus key for about 3 seconds: Shuts all NHB-18NS illumination off. Pressing
again both keys for 3 seconds will restore illumination.

darTZeel NHB-18NS User Manual, version 0.93 Page 9 of 10
4. Technical data (subject to change)
darTZeel NHB-18NS preamplifier
Gain : Line 11 dB
Phono 30 to 66 dB (up to 77dB gain at output)
Frequency response : 1 Hz to 1 MHz, +0, -6 dB (depends on measurement method).
10 Hz to 100 kHz, +0, -0.5 dB (depends on measurement method).
20 Hz to 40 kHz, ±0.5 dB (XLR inputs and outputs).
Rise time : < 0.8 µs. (depends on measurement method).
Slew rate : > 88 V/µs, peak-peak.
Total Harmonic
Distortion (THD) : < 1 % from 7 Hz to 77 kHz
Temporal Distortion : None, at any level and load equal or above 50 ohms.
Crosstalk : < -90 dB from 20Hz to 20kHz.
Signal to noise ratio : > 92 dB (A), line; > 70 dB (A), phono w/factory settings.
Consumption : 7-70 watts, depending on working mode.
Size in mm : 440 x 335 x 170 (WxDxH). Total deep with handles: 415 mm.
Net weight : 23 kg, power supply 3 kg, total 26 kg
The darTZeel NHB-18NS is made to last forever by
darTZeel Audio SA in Geneva, Switzerland.
darTZeel Audio SA www.darTZeel.com
2, chemin Louis-Hubert
CH-1213 Petit-Lancy / Genève [e-mail]
Suisse

1nF 5k1 1k 510 100 3333
5757
36363030 3939 4242
5454 6060 6363 6666
MMMM MCMC/
LOAD in Ohms/nF GAIN in dB Cartridge Type
Soldered Pad =Set
For MM
MM, 1nF must
be unsoldered !!! Resistors can be paralleled: 1k and 510 both soldered give 338Ω
Unsoldered Pad
Unsoldered Pad =47kΩ47kΩ
Gain when MC setGain when MC set Gain when MM setGain when MM set
Unsoldered Pad
Soldered = MCSoldered = MC
Unsoldered = MMUnsoldered = MM
Soldered Pad =Set
ONLY ONE SOLDEREDONLY ONE SOLDERED
PAD AT A TIMEPAD AT A TIME