Tub rolling

tubes - not tubs
ecc88 - not eq88

just get direct replacements
those are good tubes

https://tubedepot.com/products/6922-jan-philips

get them low noise and matched
this is the standard issue from audio research these days

or you can buy them from arc directly, pay about double

Did you do a little service work, like pulling the valves and reseating them, first? If that doesn't work or help, question two,

Were you happy with the old sound? Have you heard someone else, use a different valve, and you liked the difference, there is a reason to change.

Does the manufacture offer any suggestions?

Regards

It is easier to roll a tub if you put it on its side, but still difficult to make it roll straight.