I ordered a Topping D50 just based on this thread and I wanted to give my listening test after several A/B tests on different configurations.
Configurations:
System A: Volumio > Rpi3b & Hifiberry Digi+Pro w/ Telema LPS > Signal Audio Toslink > Schiit Modi 2 Uber (AK4396) > Schiit Sys > DIY Mogami RCA > MAudio bx5
System B: Volumio > Volumio > Rpi3b & Hifiberry Digi+Pro w/ Telema LPS > Blue Jeans Cable COAX > Topping D50 w/ Telema LPS > Schiit Sys > DIY Canard RCA > MAudio bx5
Note: I continued the test by switching both the M2U and T50 to USB directly from my MBP playing through VOX and still had the same findings.
The songs tested were all FLAC 16bit/44.1khz. Radiohead - National Anthem, Rustie - Hover Traps, Santana - Oye Como Va (Mfsl). As well as several others of higher resolutions (24bit/48,96,192khz)
The T50 is louder so the T50 was decreased 2db and the levels were as close as I could get by ear.
Findings:
I tested and my girlfriend tested. We could clearly differentiate the two DACs.
Ultimately we both agreed that the M2U sounded better due to a more lush sound due to what we think is a better midrange and less muddled high end. The T50's highs sound thin and not as balanced with the rest of the mix. The T50 did not have as much depth and snap during claps and kicks and did not have as much body during basslines and sustained synth lines. Drums/toms don't have the same movement through the panning and depth. Vocals also aren't as lively and seem slightly more forward in the soundstage. The M2U in comparison made everything sound more evenly distributed in the mix and had more depth to all instruments (I think due to more midrange and low-end). The T50 has a much quieter white noise with no audio playing.
I could go on and on about my findings but ultimately I'm kind of disappointed. While the T50 has measured well and has some really awesome features that I do like (auto off, native DSD, preamp, etc), I just don't think it makes up for the lush full punchiness I hear from the M2U in comparison.
In the future:
I'm now thinking of getting a Modi Multibit and compare all 3. I am also going to be getting a new Rbpi3b+ and Allo Digione. Hopefully the Digione can add punch and midrange to the sound of the T50.
Last Words:
I hope this review helps some people and I hope somebody can give me feedback as to perhaps if this is abnormal of the T50 or if there is something that needs to be done to make the sound better (other than get better speakers).
I know there is a firmware update but I have no clue how to instal it since I'm on a MAC. If anyone has any input please let me know