What amp do you have? KT88s can sound different depending on the amps design. I found Gold Lion KT88 to sound very good in my Primaluna Dialogue Premium versus other KT88s. The worst was Preferred Series from the Tube Store. This doesn’t mean they sound bad in another amp so I’m not trashing the tube. It just had too much detail and energy for me.
My experience is precisely the opposite in my VAC 300.1a. Just goes to show how much the amp affects the performance of a tube.