Headphones Extremely Quiet

Recently, I’ve been plugging my OP-1 into my Warm Audio 237 Vintage EQ & Pre to add some color to the EQ when recording into my DAW. I’ve also been using cheap 1/8th" cables. I took my OP-1 on a weekend trip but didn’t get around to using it. About a week after the trip I plugged in my 1/8th" iphone headphones and the volume on them is practically non existent. Its basically un usable with headphones now because the volume is so low. I just plugged the OP-1 back into my WA237 and it seems to be able to get plenty of sound through to my DAW with great levels. In attempt to troubleshoot more, I plugged directly from the OP-1 into my scarlett 18i20 and the output volume seemed great there too. Not even remotely quiet. But any time I plug in headphones its as quiet as a mouse. Even the normal speaker on the OP-1 is so much louder than any headphones I plug into it. I would resort to just using the onboard speaker if it just had better low end but that is why I rely on headphones. Im afraid the WA273 could have damaged my OP-1 by pumping phantom power into the OP-1?

TL:DR: Headphones are so quiet they’re basically non usable.

Check the impedance of the headphones.

I believe the Impedance on audio technica ATH-M50x is 38 ohms. My 1/8th" apple headphones used to work just fine too but theyre also super quiet. Same with all headphones I’ve tried