I have the A71 (not BT) and the A70's, and yes Id say they build quality isnt maybe the best, but Ive yet to have a problem with them. Of course I take care of my things and take them on and off my head with 2 hands, plus I sleep with them on at night (I have a strange sleeping environment) and again, have yet to show signs of coming apart, and have had them for about 6 months now, and are used all night and all day, so though they may feel like they would fall apart, have not.
If not sure on getting the BT version, if you search up Oneodio A71 and should find them used for $16, and as far as I can tell used means the box is busted up but the headphones are new for I bought 3 more at that price for fear they may break, and wanted spares, but not to sure Ill be using any of them anytime soon, but the wired and BT sound the same, and in BT mode they sound almost the same minus not getting as loud.
OH and Ive gone longer than 3 days on a single charge being used for about 12-15 hours in that time, and then charged back up. If you like I can see how long one charge will last from full to dead.
As for big and heavy, Id beg to differ on that front, for they are very light, and I have to pull them all the way out to reach my ears, and I have a HUGE head....
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