I bought those IEM 2 years ago, paired with F.Audio Xs-03 and FA3. I used them shortly then replaced with other iem because of their bad sounding. Those DAPs have an output impedance of 20 or so ohms on the SE outputs and I think higher on the BAL outputs. I read that multi-BA iems are affected by an high Zout unlike DD-only iem (the TFZ Essence sound good with F.Audio daps) then the Nx7 is maybe too sensitive to high Zout (some KZ multi-BA iems are not bad paired with F.Audio, as well as the NiceHCK M6) So, my 3-star rating if an halfway between...

This is my first TFZ iem, after reading good reviews of some models I want to give a try to a DD only iem, coming from some hybrid multi-drive iems by CCA, NiceHCK and Kz. PACKAGING: The box is nice white cardboard, inside the iems placed in foam plastic, 6 pair of tips S, M and L, 3 pair white with narrow bore and 3 pair dark grey with wide bore, plus one pair M size, dark grey, attached to the iems. The cable is a good 4 core 3,5 mm, well built, no chin slider, but it comes with a velcro strip, wrapping it tightly on the cable it become a chin...

Got this beautiful item few days ago. Very classy manufacturing and UI is good enough apart from volume change, need to turn a lot the wheel, that sometimes works unpredictably. Very powerful paired with my Ultimate Ears UE900S quad-BA. The sound quality... EQ off, really impressive, powerful but not overwherming or messy bass (that lacking on my Xuelin 770c) clear mids and highs and expecially some small details I never heard before! What a bargain for this price! (edited after a firmware update that fixed some strange issues about reproducting...