After all the discussions I’ve seen last days, I’m thinking of ordering/building a RPi based Endpoint. But which one?
At the moment the DAC is Schiit Gungnir Multibit Gen5, and Bimby is also there (Gen2).
The options (from Allo.com) are:
But which one is the best at the moment?
For the gen 2 USB Bimby, you definitely want S/PDIF, not USB. A DigiOne Player would do the job well (I don’t think that DAC justifies the extra expense of the DigiOne signature). For the gen 5 Gumby, less clear. In my experience, USBridge does a pretty good job with gen 5 Bimby or other DACs with good USB receivers (eg. Soekris dac1541), but other things being equal, I’d go S/PDIF from a good quality source than USB.
But the signature has the clean power side, at the moment I’m using a 400watt HDPlex. Which has two 5v outputs, so it is possible to connect them both to the Signature. Wouldn’t that be better than the no Signature?
I have/had a bunch of different sources with different power supplies, from USBridge with SMPS at the lowest end to Auralic Aries Femto and Metrum Ambre at the highest end (that I can bother with). There are differences with different sources, power supplies, and DACs, but they are not huge, and in general I try to avoid complications like the 2 supplies of the Signature. For Gumby or Yggy, most of the evidence points to going with good quality AES sources (which is what I use with my Yggy), although some people seem happy with their gen 5 USB quality.
On my work system (Soekris dac1541) I use a Pi+Pi 2 Designs 502DAC source with S/PDIF, fed by an Audiophonics 5V LPS. I’ve compared this source with a USBridge>Singxer SU-1 DDC>I2S for the Holo Spring DAC I have at home, differences were slight and most likely due to the fact that I2S is the best input for the Holo Spring.
Overall my view of this is, either start with a basic but well regarded source (Allo, Pi 2 Designs) or go all the way to one of the top options today (which IMO is the Metrum Ambre). All the other futzing around LPSs, intermediate complications, DDCs, ends up being not worth it.
Well, you have a very good point there. I’m already losing myself in a highend and tweaked windows 10 system. 
So basically; try/start with the DigiOne (I can always use it later at the office with bimby), and when I like the rpi based systems go for the Metrum Ambre (or something else) unless I want to build it myself and spent a lot of money.
But should I go for Sparky SBC or RPi B+?
I just ordered a Canakit RPi 3 B+ kit. Board, power supply, case. Added a 16GB card for the OS. No hat at all. Based on this blog post:
Forgot to mention that the Pi 3 + piCorePlayer + CRAAP™ works well and sounds great as a Roon endpoint/streamer. Just turn on “Enable Squeezebox Support” in the settings
Be interesting to see if I can replace my Mac Mini endpoint for $60 and still get USB Class 2 output.
I just ordered the RPi B+ with DigiOne. Hopefully I can test and compare it this week.
After I will probably pickup the Metrum Ambre at a local store here to review that one.
Oke, the raspberry pi b3+ and the digione arrived today. Installed ropieee, and connect it with the first cables I found to my dac.
There was a difference, the windows 10 system with hdplex and best cables was clearly the winner, but is was close. The soundstage and position of the different elements was better with the digione, but no control in highs and lows. But who cares, € 170,- vs more than € 1500,-…
So, now change the power cables… used the 5v media output from the hdplex… just shocking!!
All the details and clarity in highs and lows are back. Is the digione the winner? Not sure yet, but it’s definitely on the same level with a cheapass Ethernet cable (vs Chord Shawline) and the AQ cinnamon coax (vs AQ usb carbon)
What’s next 
Hi Wilco
Did manage to compare the digione with the metrum ambre in the end? I’ve got the digione signature but really dislike the battery power supply and wonder if I should go for the ambre.
Ambre baby or Lumin U1 could also be options.