[quote user="mattjax05"]
I thought that signals such as Dolby and DTS can only travel through either an optical cable or coaxial cable but from the reveiver to the hi-fi amplifier the cable wont be either of these!
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Not a problem as you are only sending the front left/right channels after decoding in analogue to the hi-fi amplifier.
But we're getting terribly tied up in knots here.
The best way to do what you want is to have a receiver with front channel pre-outs, and connect from them to your stereo amplifier. You then connect your front left/right speakers to an input - let's say AUX 1 for the sake of argument - on the stereo amp, which now acts as the power amplifier for the front left/right channels, and all your other speakers to the AV receiver as usual.
Connect your DVD player and other home cinema sources to the AV receiver as usual, and the pure music sources, such as your CD player, to the stereo amp.
Set the volume control on the stereo amp to 10 o'clock, select the Aux 1 input, and balance up the surround system as usual using the receiver's test-tones.
Now when you want to watch movies and other surround sources, you just select Aux 1 on your stereo amp, and set the volume to 10 o'clock, and after that you simply use AV receiver as usual.
To listen to music from stereo sources, simply use the stereo amp as normal - all the AV processing is thus out of circuit, and you have the best of both worlds.
If you don't want to change your AV receiver to one with preouts - and we're probably talking the better part of £400 to get one so equipped - then the Niles switchbox is the most cost-effective solution to doing what you want to do with what you have now, as it should only cost you about £50 plus shipping, judging from the US price.