Thank you, Andrew, for the quick reply.
I am switching between DXD and DSD×2 settings for Qobuz playback from the Aurender N20 to the Rossini Apex and have yet to find out the sonic differences.
Today I borrowed a Rossini player and Trilogy 914 preamp to try out at home.
I first tried the Rossini straight into the ATC 50ASLs and it sounded great. I had tried the Bartok a week ago and this was a significant improvement I think. It’s certainly better than all the other DACs I’ve tried. I can hear so much of what is going on and all the sources were great, Qobuz and local NAS files via UPnP and especially USB audio via Audirvana. Have to say my (three!) CDs sounded great too.
The Mosaic app was a bit annoying as I haven’t found a way of searching my local files, but apparently I need something called Minimserver which I don’t think will run on my old Synology NAS.
I decided I wouldn’t find anything better than this so I ordered the Rossini DAC. I don’t have a fancy car so getting fancy hifi is fine.
Next I added the preamp in the chain and the result was very interesting. I really liked what it did to the sound - more laid back and very pleasant to listen to compared to the upfront sound of the single box, BUT it did sound a bit like a filter over the pure clear DCS sound to me. I am slightly torn in choosing between the option of preamp or no preamp.
The Trilogy also introduced quite a lot of hiss other HF noise which I would find difficult to live with especially as it retails at over £13k. I don’t know if hiss is normal for this type of preamp.
When I get the Rossini I will try and optimise my home network for the system and after that if I decide the single box is still not right for me I might look at some cheaper preamp options.
What you seem to be missing is the necessary server software. So ,yes you do. MinimServer is supported by dCS. it will certainly rum on your Synology :
I would go for the paid version as it has some adcantages like the ability to be customised for your needs,.It is also inexpensive.Just make sure that you install the version for Synology.
Thanks for that. Yes my Synology DS213+ is unfortunately is too old for MinimServer.
Might have to ask for advice on these pages as to which new Synology to get but I’ll sift through some old posts on the subject first in case the answer is in there.
Can ethernet streaming really match Audirvana which preloads the track into software before passing it to the streamer? Intuitively I would expect less jitter from a preloaded track.
I am not sure exactly what you mean. The architecture of, say, Mosaic or Audirvanea differ in that Audirvana is server software and control point in as a single product whereas MunimServer is separate software with ( in Mosaic’s case), the control pint being Mosaic app. Note that no misc data passes through Mosaic app which just requests MinimServer to send the file from NAS to the renderer (DAC), Both use UPnP/DNLA protocol to pass the music data to the renderer.
I have no doubt that my little answer can be unproved on by others with more extensive knowledge.
Finished my one week Rossini player home demo (into active ATC 50s) today. Ordered a DAC version which hopefully will arrive soon.
Main takeaways were:-
The Rossini was better than all the other options I tried, Maitner MA3i, Linn Select Edition Organic. Also preferred it to the Bartok (despite the lack of headphone option on the Rossini), I guess that could be predicted as it is higher up in the DCS range. Also I demoed the Grimm MU2 and Naim 333/332 combo in store.
The main thing about the Rossini was the clarity and air of the soundstage (obviously that’s what DCS does). Although I have some reservations about the slightly lean presentation with some music that hasn’t been recorded well, it excels with the music I mainly listen to which electronic/ambient (e.g. Aleksi Perala, Four Tet), singer with acoustic instruments (e.g. Sufjan Stevens, Hayley Williams) and in my experience the most difficult genre of all, metal, which it handles brilliantly.
I tried a reasonably high end preamp (Trilogy 914) with it to deal with the occasional lean presentation with some music e.g. Pale Shelter / Tears for Fears or California Dreaming > Mamas and Papas. Although it helped with these tracks I thought overall the loss of detail and air was very noticeable and not an acceptable trade off. Also I didn’t like the hiss that the preamp introduced.
I may still try try an EAR Yoshino 868 preamp as so many on here like it.
I found that setting the output to 2V did a bit of what I was expecting a preamp to do at low volumes.
I thought it was only me ! 
One important thing to be aware of is that I do not use the tubes supplied. They are good bu t my experience has been that some NOS ones may be thought superior. I use Tungsram or Telefunken PCC88. However availability is now very limited and as a consequence the cost has increased.
Although there are now some excellent tubes of recent manufacture on the market unfortunately AFAIK nobody is makes PCC88 or ECC88. Aside from the brands above I cannot vouch for others of thus type that you may find.Tube lore is very esoteric and subjective.
NB: I do not kow what EAR now supply. When Tim de P was with us these were NOS tubes ( JJ?) rebranded with the EAR Yoshini logo. It is therefore less likely that any 868 that you may hear will resemble what I have.
@PAR In a sentence, what exactly would you say the EAR does for the Rossini? Why do you prefer it to the DAC alone?
This very much a subjective matter so for me, it can make a a closer representation of the timbral qualities of orchestral and and other instruments used for classical music when compared ( as far as possible) with my (extensive) experience of live music. if done correctly this should not involve significant negative effects. Note that this has nothing to do with the "tube “warmth” often cited and which I imagine is made by those without real experience of modern tube based designs.
Were I more keen on rock and pop I might prefer direct connection however as what a "natural " sound may be is less apparent. The sound of these recordings as usually a confection created in the studio ( or multiple studios at different times) as a kind of audio collage often using effects from processors. So, if you like it, you like it as it is difficult to establish any external reference.
Incidentally I cannot say precisely what it does for Rossini as I am a Vivaldi user. However I expect similar results.