Do you hear static or a slight buzzing noise when using the OLED headphone jack? Also which model of OLED Deck and which headphones did you try using? This issue seems widespread, so I actually wonder if there are any cases of the headphone jack not having this issue. The noise is most noticeable when there is no music playing like on the Steam game selection screen.

For me, I can hear buzzing with wired generic and Skullcandy earbuds on my 512GB OLED.