MSB Technology The Select DAC User Manual page 12

Ground Jumper IN - Basic Operation
The Basic Operation provides isolation only for the DAC. This gets you half the protection available.
For full protection, be sure the jumper is in place between the Chassis Ground and Amplifier
Ground. This is the shipping configuration. NEVER OPERATE WITHOUT THE JUMPER OR A GROUND
WIRE ATTACHED.
Ground Jumper OUT - Enhanced Operation
The Enhanced Operation provides isolation for both the DAC and the amplifier. This gets you the
full isolation available. With the jumper disconnected, connect the supplied ground wire from the
AMPLIFIER GROUND lug to the chassis of the amplifier. Note this connection is dependent on the
amplifier so you will have to look for the best place to attach the wire. Generally the easiest place
would be to loosen a screw on the Amplifier Chassis and slip the open Spade lug under the screw
head and tighten the screw. The only other place a true ground may be found is on the ground pin
of the power connector to the AMP but this will not be easy to connect too.
Dual Powerbase Grounding Diagram
In this configuration you will simply lift the grounding lug jumper and make a connection from the
"Amp Ground" lug to either ONE of your mono-block amplifiers or to your single stereo amplifier.