Mackie Digital 8-Bus Service Manual page 20

TAPE CARDS
This shows the analog inputs and outputs on the Tape cards. The analog signals go in and out of the
rear panel DB25 connectors J101 and J102 respectively.
The Tape cards have their own D/A and A/D converters, therefore, only digital signals are passed to
and from the DSP board.
Pairs of analog inputs are converted to digital form, for example, input 8 and 7 are combined to form
digital signal DR4 which goes off to the DSP board. DT4 comes back from the DSP board, and is converted
to analog outputs 7 and 8.
NOTE: the digital signals shown below are named as they appear on the Tape card only. The names
are changed at the backplane board before going to the DSP baord. See the next page for details.
ANALOG
OUTPUT
This shows the
8_OUT_HOT
digital signals
8 GND
from the DSP
board, and the
7_OUT_COLD
analog output
6_OUT_HOT
signals they
become after
6 GND
D/A conversion.
5_OUT_COLD
For example,
digital signal DT4
4_OUT_COLD
on the Tape card
4 GND
comes from the
DSP board. This is
3_OUT_COLD
converted, and
2_OUT_HOT
becomes analog
signal 8 and
2 GND
analog signal 7.
1_OUT_COLD
These appear on
the DB25 output
connector J102
8_OUT_COLD
for recording.
7_OUT_HOT
7 GND
6_OUT_COLD
5_OUT_HOT
5 GND
4_OUT_COLD
3_OUT_HOT
3 GND
2_OUT_COLD
1_OUT_HOT
1 GND
20
DSP SIGNAL FLOW
DB25
DIGITAL
Connector/pin
NAME
DT4 J102-1
J102-2
DT4 J102-3
DT3 J102-4
J102-5
DT3 J102-6
DT2 J102-7
J102-8
DT2 J102-9
DT1 J102-10
J102-11
DT1 J102-12
J102-13
DT4 J102-14
DT4 J102-15
J102-16
DT3 J102-17
DT3 J102-18
J102-19
DT2 J102-20
DT2 J102-21
J102-22
DT1 J102-23
DT1 J102-24
J102-25
DB25
DIGITAL
ANALOG
Connector/pin
NAME
INPUT
8_IN_HOT DR4 J101-1
8 GND J101-2
7_IN_COLD DR4 J101-3
6_IN_HOT DR3 J101-4
6 GND J101-5
5_IN_COLD DR3 J101-6
4_IN_COLD DR2 J101-7
4 GND J101-8
3_IN_COLD DR2 J101-9
2_IN_HOT DR1 J101-10
2 GND J101-11
1_IN_COLD DR1 J101-12
J101-13
8_IN_COLD DR4 J101-14
7_IN_HOT DR4 J101-15
7 GND J101-16
6_IN_COLD DR3 J101-17
5_IN_HOT DR3 J101-18
5 GND J101-19
4_IN_COLD DR2 J101-20
3_IN_HOT DR2 J101-21
3 GND J101-22
2_IN_COLD DR1 J101-23
1_IN_HOT DR1 J101-24
1 GND J101-25
This shows the
analog signals
coming in from a
tape deck, and
the digital signals
they become
after A/D
conversion.
For example,
analog signals 8
and 7 come in on
the tape card's
DB25 input
connector J101
and are
converted to
become digital
signal DR4. This
then goes to the
DSP board for
processing.