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View Full Version : I hear squeezebox through my tv when amp is off



dazbarber
2007-04-03, 01:41
The phono (audio) output of my tv is connected to the 'Video1' input of my JVC amp. There is no connection in the other direction.

My squeezebox is connected to the 'aux' input of the same amp.

If the amp is switched off and the squeezebox is still playing music, the squeezebox output can be heard through the (Sony) tv along with the normal tv audio.

Why is this and is something wrong?

Thanks,

Daz

CardinalFang
2007-04-03, 01:53
My guess would be that the JVC amp doesn't isolate the signals electrically when they are not selected. My Copland amp for example has relays that completely isolate input and output signals when the amp is switched off or when different inputs are selected.

So it seems there is leakage of the SB output into the TV input within the amp since they will all connect to the pre amp stage in the JVC amp at some point. The output from the TV is also probably taken from a pre-amp stage in the TV audio circuits (guessing again!) so SB signal coming in from the amp via the TV audio out also gets amplified along with the TV audio in the power amp stages.

That's my theory in any case. I used to get similar effects on my old amp and the only solution was to turn off all the audio input devices when they are not being used - or upgrade to an amp that isolates inputs fully.

pfarrell
2007-04-03, 06:29
dazbarber wrote:
> Why is this and is something wrong?


I am assuming you can hear it, when 'video' is selected
and the squeezebox is driving the 'aux' signal.
I also assume that it is not full volume, but rather attenuated
so you only notice it during quiet parts of the TV show.

It it comes thru loud and clear, something is wrong.

Its leakage between the signals.
It is very common in mass market 'receivers'.


--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html