Help/Question: Replaced driver on DT 770 and now it's "boomier"

[kertesyflush]

Hi! First post, nice to meet you. Anyways, the story is that I botched my first attempt at a detachable cable mod on my beloved DT 770 Pro 80ohms. It resulted in a snapped hair wire on the left driver. I bought a replacement driver and re-did the mod and everything works just fine now, wahoo! Except:
 
The left side with the new driver sounds significantly "boomier" than the other. Almost like it's resonating a bit more. I've been burning just that driver in with a mix of pink noise and some random music to only the left channel - so far about 15 hours.  I'm trying to figure out if another 20 hours or so of burn in will even things out or if the mod happened to do something inside the cup to cause the "boominess".
 
The changes inside the cup are that I removed the stock wire, put in a 3.5mm jack, and added some hot glue around the jack (in the inside) to make sure it was sealed a bit. I did hot glue on top of the soldering points a little as well. The only other thing is that the 3.5mm jack is long enough where I think it's slightly making contact with the plastic housing around the driver. Happy to take a picture if that would help, but in all honestly it looks pretty good. 
 
Anyone experience something like this before?

 

[kertesyflush]

Welp, update: I made some adjustments to the 3.5mm jack and am pretty sure it's not touching. That didn't do much but after another day of listening and burn in the boominess is definitely lessened.
 
I'm chalking this up to burn in.