Gold Lions are generally good if upgrading from Mullard current production tubes.
In my system Mullard < Gold Lions << Psvanes <<<<< NOS Mazda (1960s). But this is only for 12AU7 tubes. I don't have experience with any other tubes.
After spending a couple days with the Gold Lion started noticing soundstage was more focused in the center. Put RCA’s in and soundstage went beyond speaker boundaries and that’s no warm up, maybe I posted to soon. I still like them but better than RCA’s maybe not. Will compare to other tubes. I might have been wrong on this one.
I only buy old stock now. Tried GL’s and Tung Sol’s but just didn’t sound nearly as good in my amps. I prefer a fuller warmer sound so I prefer RCA blackplates, Mullard long plates, Sylvania blackplates and Amperex. They provide warmth and detail without being bright. Not a Tele fan but they sound great in my phono preamp. Synergy match is at play here. Good luck with it all.
Welcome to the most consistent quality of tubes: the here today, gone tomorrow sense of bliss (or merely contentment).
There's definitely a durable difference in sound quality between vintages & makes, but it will at times seem exaggerated (often on first listen to a new make), and at other times subdued.
Good vintage tubes are consistently better at rendering spatial information than new stock. But new has its advantages - they offer a good palette of tonal balances to choose from, and (crucially) it's easy to select for low noise at reasonable prices. Some of the new small tubes (12AX7, 12AU7, 6SN7) measure extremely strong for transconductance, more than any vintage tubes you'll find. This can be an advantage in certain slots. Russian Tung-Sol 6SN7GTB sound a lot more dynamic than any vintage 6SN7 in the V2 (driver) slots of my VAC KT88 amps. In V1, old 6SN7 rube, but in V2 the new ones can't be beat.
I’ve spent some time with the GL gold pins now. Why when something is new it is exciting to listen to only to discover with time and comparing back to back to well regarded vintage tubes it is lacking. The GL is not a bad tube but compared to Tele, RCA, Mullard, Mazda, Tungsgram instruments just doesn’t have the natural tone or soundstage of vintage tubes. Fooled me.