Headphones

I recently received my HiFiMan HE400se headphones, and I am unsure how I feel about them. From a detail standpoint, they sound amazing, and bass is clear without distorting the rest of the sound stage. However, I have noticed they are incredibly sibilant to my ears. EQ has helped with Peace on Windows, but it's terrible with vinyl sources (Project Debut III, Ortofon OM10, Douk Audio U3).

In fact, I thought I had an issue with my new stylus and bought a VTF scale to confirm it was tracking properly. I tested out my vinyl setup with my Kiwi Ears Cadenza, and suddenly, the sibilance was massively reduced to the point where I could appreciate my setup again.

Coming from the SHP9500s, which are notoriously sibilant, I didn't expect to have such a problem with the HE400se. The SHP9500s sound great with vinyl. I plan on keeping the HE400se because they do sound great with EQ, but I had heard that they sounded pleasant right out of the box.

Could it be my headphone amp? I know it's cheap, but some users on this subreddit seem to have no problems with it. I'm not looking to spend much on a new amplifier, so if anyone can recommend a budget headphone amp, I would greatly appreciate it.