Popping noise? Like a snap crackel pop kind of noise? That's just the
juice burning on the coil/wick. That happens when there is a lot of gunk and it needs a cleaning, but I have some carts that just do that, mostly depends on the liquid too.
If you are thinking of buying for an ego-t, and want more than the A type (1.5ml) then get the B type (2.5ml). I have been using the A type since they first came out and am happy with it, but go with the mega if you are starting out with these and want more liquid in your tank. Why don't you try the ego-c? I am considering moving to them, but do all my own wick mods and so on, so I am thinking about going with the A type just because I have all the A type
tanks and don't want to start all over again (although my batts will still work). I am in the process of trying the stardust. One thing I like about them is that I can even fill them without a syringe, just drip it in.
If you switch to an ego-t or ego-c, also try an LR atty, it might burn your liquid better (because it is hotter).
Hope this helps
Saludos
