@mdalton - I agree that it would be possible to measure differences between streamers in a test environment that includes a known source and known DAC. But this isn’t really measuring the streamer - it’s measuring the combined system. This could still be useful, but I’m not sure how relevant the information would be for other sources and other DACs. Still, I’d love to see someone do this kind of testing.
But I think for this to be broadly meaningful, a variety of sources (and source content) and a variety of DACs would need to be used, and then a concerted effort made to correlate the resulting measurements with the way the combination sounds. All possible, of course, but probably not very practical.
@carlsbad2 - I assume you are talking about data errors between the streamer and the DAC.
As other’s have mentioned, the data from the streaming servers (whether across the internet from the likes of Qobuz or from a local server) is transferred to the streamer using the TCP/IP protocol which will fix any data errors. If the connection is so flawed that this is not possible, the music will skip or stop playing. No streamer that I am aware of will attempt to fix network data errors.
It is possible to have data errors internal to the streamer or between the streamer and the DAC since these signals (I2S, AES, SPDIF, Toslink) do not include any error detection (let alone correction). USB does include error detection, but no error correction for Isochronous audio data transmission.
I doubt very much that any decent streamer has data corruption problems within the streamer itself, but I do think it is possible that data errors could occur between the streamer and DAC, particularly if the streamer output connection has high signal noise, if long or poorly shielded cables are used, and/or if there is a lot of EMI/RFI present in the environment where the system is located.
I still believe that the larger difference between streamers is caused by timing issues and electrical noise transmitted to the DAC, but this is speculation on my part.