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Aphex
Thermionics
- Division of Aphex Systems Ltd.
Page 2-1
80-260V~ 50-60Hz
22 Watts
POWER
Line Out
Mic
In
Ch2
Digital
Audio
24-Bits
Word
Clock
AES/EBU
CHASSIS
GROUND
59887
OPTICAL
S/PDIF
OUT
INT/EXT
MODE
IN
Ch1
Return
Line & A/D Insert
Z Comp
Send
Mute
OPEN TIP
MUTES
-10dBV
+4dBu
ON
OFF
Line Out
Mic
In
Return
Insert
Z Comp
Send
Mute
OPEN CIRCUIT
MUTES
-10dBV
+4dBu
ON
OFF
|
INT
GEN
Back Panel Features
2
Model 1100 MkII Mic Preamp - Owner’s Manual
Figure 2-1 Back Panel
The rear panel hosts all power, input, and output connections of the Model 1100 MkII. This section
teaches you how to properly connect and use each interface. Most users will probably find the back
panel completely self explanatory, nevertheless we suggest that you read the commentary carefully
to avoid any possible misuse or confusion and assure that you are getting the maximum performance
from your microphone preamplifier.
2.1 Power Entry
The standard IEC power receptacle automatically
accepts any normal a.c. power source from 80 to
260 volts, 50 to 60Hz. You don’t have to set a
voltage selector and there is no replaceable fuse.
The internal power supply is self regulating and
self protecting. If the internal fuse should ever
blow out, then a catastrophic failure is indicated
requiring service by a qualified technician.
2.2 Chassis Ground
Connecting this ground is not essential in most
cases since the power cord will usually provide
the proper safety ground to the unit. However,
in case you encounter hums, buzzes, or radio
interference, you may be able to eliminate them
by connecting a separate, heavy gauge, system
ground wire to this screw. This is especially help-
ful if the unit is not installed in a rack having
grounded metal rails that would act as a chassis
ground source. You can try connecting the chas-
sis ground to the mix console ground, or the
chassis of other equipment, for example.
To meet legal requirements, we have not pro-
vided a means to lift the power cord ground from
the chassis. If you determine it is necessary to lift
the power cord ground, you must use a ground
lift adapter on the power plug. You will not be
able to lift the power cord ground from inside the
chassis.
2.3 AES/EBU Digital Audio Output
Preamplifier channels 1 & 2 are encoded into
the respective AES/EBU channels (ch1=left,
ch2=right). The standard 110 ohm transformer
balanced output will interface with any standard
AES/EBU input. Be sure you use professional grade
digital audio cables to insure high quality trans-
mission of data. Low grade cables or plain audio
cables will severely limit the transmission distance,
and, even worse, induce a large amount of jitter
into the data stream.
In case you get no output signal, check the front
panel to be sure the clock is locked. If external
clock is selected and there is no external clock
source, the AES/EBU output will be squelched
and you’ll get no output. In all other cases you
should get an AES/EBU output signal if the unit
is functioning properly. Before declaring that you
have no output signal even though the clock is
locked, be sure your receiving equipment is able
to lock to the sample rate you are using. Many
pieces of gear are not yet capable of receiving the
96KHz sample rate.
2.4 External Clock
Two BNC jacks are provided to permit multiple
Model 1100 MkII’s to be daisy-chained together
from a master clock source. In trying to simplify
the way things work, and we have made every-
thing pretty much automatic for you. Neverthe-
less, please take the time to study their usage
before planning your installation.
2.4.1 Clock In
This BNC jack is provided to receive your master
clock source. It will accept industry standard Word
Clock, from 1 to 5V pulse amplitude. It does not
accept AES/EBU or Superclock.
The Model 1100 MkII can operate equally well
from a typical “brute force” 5V word clock output
Figure 2-2 Digital I/O & Clock