And I am the unlucky one. All three TRN products (BT20S, BT3S, TRN 8 Core MMCX cable) I purchased were defects.
sympathies, it sucks to buy products (even if some consider them "low" or even budget) and when they are broken
out of TRN V90, V90 (V90 twice, yes), BA5, ST1 - the first V90 had issues on the right side that the sound lowered, even stopping output (could have been partially due to ear canal though [pushing in too deep seems to have a weird effect that output is affected] and that I used them for sleep, lying on side) - however the situation rectified itself after some time of using foam tips
so 3/4 or 4/4 are working well
the KZ AS10 had no issues so far, don't have any CCA yet