Setting the Grounding Option Switches
The settings of the 8 DIP switches on the bottom of the unit determine
if and how input and output shields are connected to the case,
denoted
at the terminal strip, and to each other. Switches 1 through
4 apply to Channel 1 and switches 5 through 8 apply to Channel 2.
Normally, the shield of any balanced audio cable should always be
solidly grounded at the send (source) end. At the receive (load) end,
there are disadvantages to both solidly grounding the shield and leaving
it disconnected (floating). An RF damping network, which effectively
disconnects the shield at audio frequencies but grounds it at RF
frequencies, usually offers the best overall performance.
This configuration is achieved by the as shipped settings as shown in
the drawings. These settings, switches 2 and 6 off (open) and all others
on (closed), will give the best results in most systems.
If a pin 1" problem exists at the output
of the signal source equipment, it can
usually be eliminated by opening S1
and/or S5.
About Floating Equipment
Equipment which has a 2-prong power cord and has no other ground
connections through other signal cables may float at a relatively high
voltage (approaching line voltage, but harmless because of the limited
leakage current) above the ground voltage reference for the remainder
of the system. If the output of the PC-2XR drives such equipment, hum
may still be a problem because of the high common-mode voltage.
In these cases, it will be necessary to connect a
wire (gauge unimportant) between the case,
denoted
at the terminal strip, and the
chassis of the piece of equipment which the
output drives and close S2 and S6. This
reduces the voltage between the floating
equipment and the driving equipment without
passing the small AC line current through the
shield of the output RCA cable, which would
produce hum. If the PC-2XR is connected via
rack mounting to the equipment being driven,
this is unnecessary.
If You Need Help
If you experience difficulty or have technical questions, our staff engineers are available from 9 AM to 5 PM Pacific time,
Monday through Thursday, by calling (818) 374-5857. You may also reach us by FAX 24 hours a day, 7 days a week
at (818) 374-5856 or e-mail us at [email protected].
Several Jensen application notes discuss the technical aspects of grounding and interfacing in audio and video systems.
They are available free on request. This information, as well as data on our full line of products for audio and video, may
be obtained from our website at www.jensen-transformers.com.
is a registered trademark of Jensen Transformers, Inc.
©
1998, Jensen Transformers, Inc.