Originally Posted by sportflyer
The new target DAC will have both Toslink and Coax S/pdif . It should be able to accept 24 bit/192 khz . I totally agree we should stay with digital right up to the DAC
If I limit the resolution to what Toslink can support , could I not use the TV's HDMI Toslink audio return to feed the DAC like so:
Computer>Receiver ( via ethernet) >Receiver HDMI out>TV Audio Return( Toslink) >Ext Dac >Preamp etc
BTW what is the format of the signal in the Toslink HDMA audio return path ?
If the above signal chain works , it would save me having to buy more hardware.
HDMI would have up to 192/24 PCM.
The S/PDIF is interesting. I had always been taught that the maximum clock was 48kHz on both optical and coax S/PDIF. I just did a look-up and there are DACs (probably like yours) that support 192/24 over S/PDIF. However, that doesn't mean that all S/PDIF sources/sinks can support the higher clock rates. Just ones that were designed for it. It's a non-standard standard.
So what that means is that I think it is highly unlikely that a TV would be able to support that rate. You would have to try a specific TV model first to be sure with 192/24 audio. I would also be surprised if the HDMI overlords allow 192/24 output from HDMI as anything but HDMI. I suspect there is a downconversion that would occur. My other concern is that I wonder if a standard TV wouldn't convert to analog first (have to add bass, treble, volume) before converting back to digital and sending out over S/PDIF?
I don't hold out much hope of your plan working, but then again, I haven't tried it.
The best methods for doing what you are trying to do seem to involve USB or IEEE-1394, both of which can handle the higher clocks.
Now, if you are willing to accept that you are running 48/24 then it should work (may be 48/16). However, at that point I'd say the Onkyo at 192/24 should provide you better quality than any DAC running 48/24 (or 48/16). Of course to my ears, once you get to 48/24, anything above that I really can't hear a difference (actually 48/20, but that has become non-standard). After 48/24, the recording/mixing/mastering chain introduces much more noise than anything in the playback chain.