UAE23HD USB Type C DAC (Sabre ES9018 + SA9023)

This is the third purchase of this product. The first was very good with a smooth mid range. Overall sound was excellent but slightly muted with my HD650. The second purchase was very bright with mids that were not as smooth. Highs were sibilant. Sound was a bit louder than the first. I decided to send the second purchase back and try once more.The third purchase was a dream come true. The mids were extremely smooth and clean without a hint of harshness that was evident with the second purchase. Very clean and transparent sound.As a matter of fact the sound was so impressive with my HD650 that i would gladly pay a much higher price for this speciman.It appears to me that there are significant differences between various specimens that should be taken into account when purchasing. I now understand why some people perceive this device as being bright and edgy and others feel it is very clean sounding. It might just be the variance in sonic smoothness from one sample to the other that causes the difference in opinions.Just to clarify the second purchase was not acceptable. The first and third were fine with a bit more sharpness with the 3rd purchase. The first purchase worked best with my HE 400i. The third was best with the HD650.Update May 6th 2018Unfortunately the product started to go on and off when usb was slightly moved. For example if phone was held in different position the device would shut off. No problems with my first purchase that i still use.Update nov 1 2018Using this dac with massdrop CTH amp. Excellent sound especially with my hifiman 400i. Extremely smooth and extended sound. The sennheiser 650 sound very good but not in the same league as the 400i which tend to be bright but with this combo it has silky smooth sound.