Unfortunately…Hmm… then the fault is in the Yamaha wxc50 that in AirPlay mode, both as ”player” and as ” pre amp” modifies the sampling frequency to 48 kHz ? Thats bad if its true.
I might be wrong, but as I understand it, the Douk Audio U2 has no internal clocks, but the Door Audio U2 Pro does have three internal clocks (you can also choose higher-end clocks, quadrupling the price from ~$50 to >$200, if you order from eBay/aliexpress).3. Douk audio U2 - a chinese USB bridge with xu208 and three different clocks , very small and neat.
The Douk U2 ( not PRO) has three different clocks, on the left side x1,x2, x3- one for each sample frequency.I might be wrong, but as I understand it, the Douk Audio U2 has no internal clocks, but the Door Audio U2 Pro does have three internal clocks (you can also choose higher-end clocks, quadrupling the price from ~$50 to >$200, if you order from eBay/aliexpress).
You are very right. Blind test is a wrong method.This is no science test , agree. Just listening for hours and days.
With blind testing bias, I ment that its a risk listening only to the details of the sound instead of the emotions of the music in a blind test situation with quick switches.
Listening long term is ofcourse not free of bias , but it shows up the faults or the benefits when enjoying music while relaxing.