Got my Dark Saber a week ago. Left side 2 pin connector fit pretty tightly compared to the right. Tried to swap to using my Littlewhite and pulling the stock cable out pulled out the whole 2 pin socket and some of the shell. Reached out to Moondrop, they told me to contact the seller. Reached out to Apos, they told me to pay $425 for a replacement but could offer a 35% discount.
This is definitely the last plastic IEM I get that doesn't fill most of the shell with resin, and probably the last Apos or Moondrop purchase I make.
https://preview.redd.it/sftlhii1g8wb1.jpg?width=425&format=pjpg&auto=webp&s=90353bded1a87ff94141b68440ea1e6125a3b8e0
The ef600 has 32 ohm output impedance. That's going to have an effect on the FR of almost every IEM on the market.