Should have seen this before I bought a used Mytek Brooklyn DAC (original version with latest FW)... Anyway, I don't like the sound of the DAC except that the display looks pretty cool. Should have noticed that having some chips "sanded off" the marking it's quite a red flag... BTW, I did use the 4 jumpers because it clipped the input of my integrated tube amp (Glow Audio Amp Two).
Even before reading this I found that with MQA disabled the DAC sounds a bit better, especially with songs mastered really hot and compressed. Also even when set to 0 level on analog, bypass will make the sound output different (cleaner but "brighter"). It also introduces some slight pops occasionally on my optical source input and it sounds worse that I remember when connected to either a Cyrus One HD or my trusty Sony HAP-S1. Anyway, it sounds very bright and somehow caused my ears to hurt after listening for 5 mins... even with a tube amp. My speaker is a pair of full-range single driver speakers (Omega Super 3 XRS). The Sony HAP-S1 never sounded like that.
On a side-note, due to the high efficiency of my speakers I cannot use the Cyrus One HD which has a complex background noise (pulsating with some high freq content).