(09-Mar-2015, 22:36)Ron D Wrote: yes my source (Oppo 95) has both digital and analog outputs. Its entirely possible that the inputs on the 200 sound different but if the 200's DAC is treating/digitizing the same source file the same way, albeit one from coming in via analog inputs and the other from the digital input, one could assume the same output would be the same????
Let's assume that your source is a CD, DVD, etc. -- in other words, it's a digital representation of the original analog sound. So the Oppo can read the digital stream off the disc and can deliver it, error-free, to a digital input of the 200. That input is in the "native" form for the 200, which works mainly in the digital domain. So in a sense it's the simplest path from the original source (CD, DVD, ...) to the loudspeakers. There's the ADH magic and any signal processing (e.g. SAM, filters, etc.) going on inside the 200, of course.
If you instead take the analog output from the Oppo to an analog input on the 200, you've now inserted two additional blocks of circuitry. One is the digital-to-analog converter inside the Oppo, and the other is the analog-to-digital converter inside the 200. Once the signal has been through both those blocks, it's back in the digital domain and is processed in the same way as the digital input would have been (SAM, filters, ADH, ...). However the digital-to-analog-to-digital conversion you've introduced probably means that the digital signal the 200 is working with isn't
exactly the same as it would have been if you just fed it the digital output from the Oppo in the first place. So there is the possibility that you might hear a difference in sound quality. How different it is -- and whether it can be heard -- depends on the faithfulness of the digital-to-analog and analog-to-digital conversions you've added to the signal path, as well as the possible effects of the interconnect cable between the two devices.
(09-Mar-2015, 22:36)Ron D Wrote: If I were sending a 44.1 Hz file via digital cable and the same music was coming into the analog inputs and being sampled at 96 Hz then I would expect there would be sonic differences.
(Incidentally, when you say 44.1 and 96 Hz, I guess you mean 44.1 and 96 kHz.)
Sorry to sound like I'm being pedantic, but it probably depends on exactly what you mean. The digital version is a representation of an analog signal with samples taken at a rate of 44.1 kHz. If you take the original analog signal and then sample it independently at 96 kHz to create a digital stream, yes, the samples in the two digital streams will be different. But according to sampling theory, they will both allow the original analog input to be reconstructed completely accurately by a digital-to-analog converter provided the original input doesn't have any frequency components above 22.05 kHz, that is, half the sampling frequency. (I'm not a mathematician or audio engineer so I might not have stated that quite correctly, but I think the gist of it is right. Don't be confused by the diagrams that show "staircases" and what not -- they are misleading.) So the upshot is that there's no reason in theory why there should be a sonic difference between the two cases.
If the analog-to-digital or digital-to-analog converters are implemented badly, that's a different matter, of course. That's down to the quality of engineering and real-world behaviour. Whether that results in audible differences is largely subjective because the measured performance of these things is now very good.
By the way, at least one other person on this forum has done quite a bit of critical listening and come to the conclusion that the 200's analog-to-digital conversion has no subjective, audible effect on the sound quality.
(09-Mar-2015, 22:36)Ron D Wrote: In the end I love the 200 I just want to better understand how it treats the music as it enters the unit and then travels around within the 200...
Agreed! The architecture of the Devialet amplifiers is quite unusual and I think many of us are still learning about how they work. What I've written above is based on my understanding, and is hopefully not too far from the truth.
