What are the differences between the RAW Pro DAC-1 ans the SMSL SU-X? Has anyone compared the sound?
The RAW Pro-DAC-1 uses an ES9039MS PRO, and the SU-X has two ES9039MS PRO DAC chips.
The RAW Pro-DAC-1 uses switching power supplies, while the SU-X uses transformers. In the past, I wouldn't have owned audio devices with SMPS; today, I'm very skeptical of such devices with transformers.
The RAW Pro-DAC1 has a high-quality housing and is likely identical to the usual suspects: the SMSL DO400, DL400, Loxjie D40 Pro, and D60. The devices differ in their housings and displays, and, unlike the RAW Pro-DAC1, they have a very good, high-quality, true balanced headphone amplifier with 4.4 watts.
In Amir's test, the Loxjie D40 Pro had a SINAD 0.1 lower than the RAW Pro-DAC1, i.e., 123.3 versus 123.2. This is more due to device variation or measurement inaccuracy than to any real difference.
The Loxjie D40 Pro is currently available at Amazon.de for €319.99. The money saved would probably be much better spent on headphones or speakers, as you won't find any difference in sound compared to the RAW Pro-DAC-1 or SU-X.
We conducted a very complex blind comparison with several people, including the SU-10, SU-X, DO400 (identical to the Loxjie D40 Pro), and so on, and there were virtually no differences in sound or anything attributable to one device. Especially not better or worse.