Madrigal Imaging N380 - Manual (Page 33)

33
wiring diagram using an SSP
LF
RF
Ctr
RS
LS
Listening Room
video 1 video 2 video 3 video 4
Surround Sound Processor
Sub
Surround Power Amplifier
Center/Sub Power Amplifier
Main (Front) Power Amplifier
RF LF
RS
LS
Ctr
Sub
LF
RF
MADRIGAL AUDIO LABORATORIES
R
display intensity
monitor record select balance
inverted
polarity
mon o 1 2 3 4 5 6 standby
PREAMPLIFIER Nº 380
mode
mute
noise in a/v systems In some cases, connecting your audio and video systems together can result in
noise, typically a 50/60 Hz or 100/120 Hz hum. The most common cause for this
noise is a “ground loop” caused by the presence of two ground references in the
system: one from the power company and another from the cable-television com-
pany. The simplest way of solving this problem is to break the cable company’s
ground by using an isolation transformer on the incoming cable line, before it
reaches your television or VCR. If you cannot find a 75
Ω
-75
Ω
balans (isolation)
transformer, you can easily construct one from the adaptors which probably came
with your VCR and television, as shown below.
75
Ω
300
Ω
300
Ω
75
Ω
Ground Isolation Adaptor
place in-line with your cable feed, prior to the system connection
The assembly shown above may cause some loss of video signal strength and/or
bandwidth, and should be used as a temporary fix. It is useful in determining the
cause of some video-related noise problems, however, and costs only a few dol-
lars. If it seems to correct a problem, consult with your dealer regarding a long-
term solution which does not degrade video performance.