Owner manual

Page 12
MICROPHONE PREAMPLIFIER
Page 13
Instruction Manual
3. INSTALLATION
This connector pinout matches the Tascam Analog DB-25 connector that has also been
adopted by many other manufacturers such as Mackie and Yamaha. Ready made cables
can be purchased to connect with other products, or to obtain a break-out to XLR plugs.
Refer to Sections 5 for more information about using the Main and Aux Outputs.
3.7 INPUT TRANSFORMER MODE
The 1788A’s Jensen® microphone input transformers can be operated in one of two
modes: LOADED and UNLOADED. The loaded mode places a load resistor on the
transformer secondary according to the transformer manufacturer’s specifications. This
maximally flattens the frequency and phase response between 20Hz and 20KHz. The
sound, of course, is outstanding. We have received many kudos. However, in our design
lab we discovered that leaving the transformer unloaded opens up the definition and
adds “sparkle” to many microphone sources. For analog and digital recording we feel the
user may deeply appreciate this added dimension, so we gave you a jumper option. The
LOADED mode is shipped by default, and the user will have to change the jumper to try
the UNLOADED mode.
CHANGING THE MODE
Remove the 1788A’s top cover and locate the set of
jumper pins JP1 and JP2 near each transformer. Move the
shorting device to the appropriate position as shown in the
illustration below (one jumper must always be left open).
3.8 MIDI CONNECTIONS
The external remote control is based
on MIDI protocol. The Model 1788A
is fitted with MIDI and Ethernet
ports for this purpose. MIDI data is transmitted via a special five-
conductor cable. Not just any 5 pin cable will suffice for proper
operation. MIDI cables are specially grounded and shielded to ensure efficient data
transmission.
MIDI CONNECTOR
Only the MIDI Out and MIDI Thru Ports connect Pin #2 to Ground.
NOTE: Remote control software for the 1788A is continually under development and
will go through new releases from time to time. To avoid obsoleting this manual,
we have moved the instructions covering remote operation to a separate dedicated
manual. Please locate and review that manual when planning your remote control
system.
(LOADED) JP1
(UNLOADED) JP2
INPUT
XFRMR
MIDI
IN OUT THRU
1
2
3
4
5
Not Connected
Data +
Data -
Ground
Not Connected