Some interesting posts in this thread. I would make a simple point. It is easy to think that you can add some kind of music server to your Devialet, something costing quite a bit of cash, and this should give you some sonic advantages over a Mac Mini running AIR, or indeed a PC for that matter. From my experience, this is not necessarily true, but neither is it a straight forward question to answer.
When I first had an expert amplifier I mainly used it via AIR. I had read a few reports of people trying alternatives to AIR, with mixes results, although perhaps unsurprisingly when somebody reported that 'product X' sounded better than AIR, 'product X' was generally something fairly expensive. With my own experience, I found that the kit that I thought was a definite step up from AIR was almost always kit that could feed the Devialet via AES/EBU. The Aurender N10, W20, dCS Vivaldi upsampler are all superb with an Expert. I then ran a combination of the microRendu and Mutec MC3+USB with my Expert, this too was small step up from AIR, with the bonus of excellent functionality and bullet proof stability.
The product that disappointed a little with the Expert, for me at least, was the Melco N1Z. In some respects, the Melco was indeed better than AIR. In fact, I can recall the N1Z sounding remarkably good, it is just that to my ears it lost out slightly in terms of bass accuracy. I have some theories here, relating to the Devialet's USB implementation, leakage loops and so on, but this can only be conjecture. The one product that I have listened to with an Expert that did not appear to suffer from this was the CAD CAT, which I auditioned with it's ground box device. It's interesting to note here that UK magazine HiFi News and Record Review run a D800 as a reference amp with a Melco feeding a Mutec MC3+USB which feeds the Dev via AES/EBU. Seams an odd choice of reference amp now that the 1000Pro exists though.......
OK, so that is with the Expert, but I think things are very different with the Pro. Earlier this year when Roon AIR emerged, I thought I would try AIR with my Pro. It is fair to say that I was very surprised just how good AIR is with the Pro. So with the Expert, my microRendu + Mutec combination gave a nice lift in sound quality over AIR, but with the Pro, I would say that the differences between AIR and the Mutec have shrunk to being tiny. For the record, I still use my mR+ Mutec combo, a case of it having exactly the functionality I want, perfect stability, and maybe an absolute fraction of an SQ advantage. Although I already own the mR+Mutec, I would say that it would probably not be worth the cash buying it again new for the Pro, highly debatable at best.
More on that topic here:
https://devialetchat.com/showthread.php?tid=4427
The above linked thread should at least provide food for thought for those thinking of spending reasonable cash for a music server for an Expert. In crude terms, you could spend 3K or 4k (or more) on a music server for an Expert which offers a sound quality hike no bigger than the SQ difference between AIR on an Expert and AIR on a Pro, so maybe simply going for the Pro when the upgrade scheme restarts might offer the best 'bang for buck'?
I think all this leads to a new question, that is what would offer a decent sound quality hike over AIR with a Pro amplifier. My feeling here is that nobody can possibly know the answer to this, not yet at least. Consider that nobody has yet spent any time listening to the new Devialet OS Board. (Except Devialet, assuming they actually have got it working) Also consider that the new OS Board provides a new specification USB input. So all the stuff that has been posted on this forum to date regarding the differences between AES/EBU and USB with the Expert becomes irrelevant, or at least needs revisiting, for Pro spec amps. As an example, maybe that N1Z will become the killer from end with the new OS Board spec USB, who knows.
The OS Board upgrade programme has now stuttered into life and the first upgraders should be getting their amps back soon. So before too long we should get some reports as to just how good it is for sound quality. My guess is that it would need something like a Mutec MC3+USB with the Mutec REF10 to significantly beat it for sound quality, in fact I think you would need something like the Mutec MC3+USB with the Mutec REF10 to be significantly better than the current AIR with the Pro. The OS Board is a complete unknown at the moment. How will it compare with the current 'good stuff', like the big Aurenders, dCS Vivaldi etc.? We can guess of course, but nobody knows at the moment.
