darTZeel Audio NHB-108 B version - Manual (Page 11)

darTZeel NHB-108 model one
User Manual, version B 1.0 Page 11 of 35
6.4. Jumper settings
Before making any change in the jumper set-
tings, power off the amplifier, REMOVE the AC
cord, and wait for 5 minutes before removing
the glass cover.
On the inside rear panel (see chapter 3.3. "Top
View", no. 11), where the input circuit boards are
located, you will see 3 jumpers per channel:
Fig.3 – Jumpers
2 jumpers are labeled Ground LIFT and XLR pin
1 FLOAT. They can be changed over in the event
of a hum problem when an XLR input is used, de-
pending on the circuit design of the associated pre-
amplifier. In a lesser extend, these jumpers may
also affect RCA inputs. Their factory default posi-
tion is the most commonly used in order to obtain
best results.
The third jumper, labeled DC Offset COMP is the
most important one since it does affect the sound of
the amplifier.
This jumper is set to ON at the factory, preventing
any problem of DC offset due to AC voltage varia-
tion or too great an ambient temperature change.
If your AC mains voltage is stable, and your listen-
ing room is at standard temperature, we recommend
removing the compensation by putting the jumper
to off.
In doing so, you will fully benefit from the very
philosophy of the NHB-108 model one, which is
to refuse any compensation or global negative feed-
back which could impair the sound. Most users
have reported to us that this setting has the best
sound. Depending on your own audio system, this
result may vary, however, so experiment for your-
self.
7. Maintenance
7.1. Fuse(s) replacement
The following procedure concerns the left channel.
For the right channel, the procedure is the same but
that the fuse is in a mirror image configuration.
If one – or both – fuse(s) has/have blown, first try
to determine the cause.
The Crowbar circuit installed in the darTZeel
NHB-108 model one
causes fuses to melt when an
abnormal situation is detected. This is normal be-
haviour.
For more information about this topic, please refer
to the technical section, chapter T6.
If a newly replaced fuse immediately melts when
you power on your NHB-108 model one, even
though your speakers are correctly connected to the
Speakers Terminals (6),
unplug the AC mains and
contact us directly:
[email protected]
Hereunder is the procedure:
In order to change a fuse, power off your NHB-108
model one
by pressing the Power Nose (3) button.
!!! UNPLUG THE AC CORD FROM MAINS, and
wait for 5 minutes !!!
Remove all the input and output connections.
Remove the single central screw located on the top
smoked glass cover. Take the two supplied suction
grips, slightly wet them in order to provide strong
vacuum, and firmly apply them on the cover glass,
as indicated in Fig.1
Please be careful when removing the top cover,
since it is of real glass, not Plexiglas
TM .
Put the amplifier on a carpeted surface, and gently
(but firmly, as it is a heavy, 30kg electronic crea-
ture) pivot it vertically onto its front handles. Use a
protective cloth as indicated in fig.4 in order to
avoid scratching the inside aluminum parts
Fig.4 – Soft cloth