The iMac G5 has an optical output rated at 130db signal to noise ratio. I'm looking for suggestions for a H.T. receiver that will do justice to this signal. IOW has a quiet pre and amps with a respectable SNR. I'm aware of the good results with the Pioneer 1014 and the offerings from HK, but I was hoping there was something with a smaller form factor that would do the job. The amps need not be huge as this will be for near field listening. Good SNR is the top priority. TIA.
I'm a little unclear on what noise represents in a digital, optical output. The photons are either flowing or they aren't. Instinctively, I think this is a marketing number, not a reality. Without getting into a discussion of quantization error in digitally recorded music, I think they are (dishonestly) trying to say that optical digital outputs, being both optical and digital, introduce no noise whatsoever. That's a safe and easy claim to make, since noise happens in the receiver, when it converts the digital data back to analog.
In analog audio (like a receiver), a 120db S/N is considered phenominal, and I can't think of an amp that actually reaches it. (I've seen one claim of 115db S/N in a unit priced at 46,000$). I don't think any receivers get to 110db, let alone the 130db you ask about.
For typical nearfield, you can probably manage just fine with 100db S/N. Look at Onkyo receivers for a start. If you seriously need more, open the wallet wide and start buying separate components. Bryston amps achieve 113db S/N on a good day, and the prices aren't stratospheric compared to other high end gear. (Compared to receivers, yes, they are.)