Madrigal Imaging N380S owner manual Ground Isolation Adaptor

wiring diagram using an SSP

noise in a/v systems

video 1			video 2				video 3	video 4	LS		LS
									RS
										Surround Power Amplifier	RS
			Surround Sound Processor						Ctr		Ctr
						LF	RF		Sub	Center/Sub Power Amplifier	Sub
display									RF		RF
intensity							inverted
						mode	polarity
										Main (Front) Power Amplifier
								PREAMPLIFIER Nº 380S	LF		LF
	monitor		record select			balance
mon	1	2	3	4	5	6	mute	standby
o
									Listening Room

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 75Ω -75Ωbalans (isolation) transformer, you can easily construct one from the adaptors which probably came with your VCR and television, as shown below.

Ground Isolation Adaptor

75Ω 300Ω 300Ω 75Ω

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.

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