THE BACK PANEL
Top drawing: ELCO configuration
Bottom drawing: DB-25 configuration
A B C D E F G H I
A. Power Switch: Where the IEC power cable is inserted, the fuse is placed, and the power is switched off and on. Most
users should be familiar with this feature set.
B. Output L/R (x2): Two sets of balanced outputs, typically going to your favorite A/D converter and a monitor controller/VU
meters.
C. Mix Input L/R: These inputs feed the FADER in MIX mode. See page 15 for more details.
D. SUM-DIF Outputs: The outputs for the raw encoded signals (unprocessed by Inserts 2 & 3). SUM signal is attenuated
6dB, DIF is boosted 6 db to bring them to “normal” levels that are easier for most outboard gear to process.
E. PATCHABLE Sends/Returns: Factory-wired to patch into Insert 6, but internally user-adjustable. See page 18 for details.
F. Inserts 5-8 connectors*: ELCO/DB-25 connectors for the last 4 inserts.
G. Inserts 1-4 connectors*: ELCO/DB-25 connectors for the first 4 inserts.
H. Selected Input L/R: The selected input’s dry signal comes out here.
I. Inputs: 3 sets of inputs for whatever you want to plug into the BACKBONE. We recommend audio sources; you can try
plugging in your toaster, but it probably won’t sound very good.
*In the ELCO configuration, two 56-pin ELCO connectors handle all of the inserts. In the DB-25 configuration, four 25-pin
connectors do the same job. For the ELCO pinout, see page 19; for the DB-25 pinout, see page 20.
IF DRIVING ANY UNBALANCED LOADS, READ BELOW:
If you are planning on driving any unbalanced equipment with your BACKBONE, you must make sure
to FLOAT PIN 3. If Pin 3 is grounded, there is a possibility of damaging the BACKBONE, or at
least introducing unwanted noise into the signal path. Lifting Pin 3 will allow you to drive unbal-
anced equipment, but please note that this scenario will lead to a 6 dB drop in level.
This applies to ALL outputs, including those on the ELCO/DB25 snakes.
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