Depends on the layout of the amp, which I'm not familiar with. It all depends which tube or tubes handle input. Similar tubes may be just phase inverters, so less crucial. Mullard, Amperex Bugle Boy, and Telefunkun are all good but on spectrum, with ABB in the middle.
Preamp tube
Any suggestions, I’m considering changing the V1 preamp tubes (12AX7/ECC83) on my Jolida 1000 integrated amp. Right now I am using Genalex Gold Lion’s. Any thoughts and what the benefit will be from the suggestion?