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 Post subject: Ac-3 RF to Analog input
PostPosted: 05 Jul 2017, 14:39 
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Couple of days ago I made a mistake hooking the audio inputs from my 704 to my amp. I use composite jacks for all my connections so it gets confusing, Ac3 out was not working so I checked everything, I was using a red rca for both analog and Ac3 rf, somehow they got switched resulting in Ac3rf raw signal going into the analog R channel on my amp.

when I tried to play a disc, I could hear what sounded like the disc "spinning up" coming out of the right channel.
I suppose frequencies being picked up by modulated RF signal, but I really don't the science behind it
Found it interesting though, anyone else ever do this (by mistake or otherwise)
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 Post subject: Re: Ac-3 RF to Analog input
PostPosted: 05 Jul 2017, 22:31 
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The AC3 RF output has a 4V DC offset applied to tell the demodulator when to operate or to mute. I'd imagine an audio jack is robust enough to withstand the signal but I wouldn't want to try it out for myself!
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 Post subject: Re: Ac-3 RF to Analog input
PostPosted: 06 Jul 2017, 00:23 
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There is a 300mV Peak to Peak FM modulated signal that rides on the DC levels. Your receiver was playing what it could as you suspected. The 4VDC was not an issue as receiver/processors commonly AC couple or balance the inputs to remove any DC offsets.
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 Post subject: Re: Ac-3 RF to Analog input
PostPosted: 06 Jul 2017, 04:12 
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Thanks for the info
I did not get the impression that anything was damaged, but I still corrected it as soon as I noticed!
everything is now working as it should (knock on wood).
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