If you want a little nugget for Mac, don’t use Golden Lyon, for signal valves. Mac used GL to voice MC275, but only their power valves, but never their signal valves. Mac used Tellies, Amprex, (Mulards), RCAs (if you can find BP), Volvo. PSVANE is a GREAT valve, and getting better. The stocks valves, are ok at best, like JJs. They are probably the better of the bunch, top to bottom, for cheapos.
Like I said, if you can’t hear the difference, don’t waste your money. Some can hear the difference, some can’t.
Swap to Sylvanias, if you can’t hear that difference, you know. But, you have to be honest with yourself. They should blister your ears, if they don’t in any Mac 1959-2020, there is a hearing issue, with a health Mac. Unless you don’t use a tweeter.
Regards