I have a Cayin A-50T tubed amp. I have really enjoyed it so far, and have spent some time reading reviews on-line. Many state that "once I replaced the tubes with xxxxx it sounded fantastic". I have also heard of rolling tubes.

So, is rolling tubes the same as replacing tubes? If so, is this just a matter of taste or are there really significant upgrades I can make here? I am new to this, but I think what I have sounds really good now - but I wouldn't mind experimenting.

Advice / tube recommendations?