Kaossilator Pro + Distorted Headphone Sound Issue HELP

[yungsage]

Recently started using the old kaossilator pro +, because it has been laying around for a long time, and I really got into it. However, I've always been having this weird issue where some of the drums get REALLY distorted or start clipping on high volume. This issue only happens when using my headphones. let me explain:

My setup is headphones plugged in the headphone port via 6.3 mm using a 3.5mm to 6.3mm adapter. I've tried different headphones and all of them had the same distortion issue. (Keep in mind the headphones work perfectly fine on my computer).

However, when plugging in a small speaker (via headphones port using a 3.5mm to 6.3mm adapter as well), it sounds perfectly fine on any volume, which makes no sense. Is the port broken? Is it a problem with the adapter? Do my headphones suck? WHAT'S THE PROBLEM HERE? Any help or guidance is greatly appreciated.