Would also love to hear about differences people have heard when using higher end amps / preamps with the rarer, and less obtainable NOS tubes.
I’m currently running a set of first issue Telefunken 7DJ8 and a set of Philips 1955 EL34 metal base in an amp. I am thinking about trying to find a set of unobtainium Siemens CCA or the like, but just not sure if they’re worthwhile if I could find them.
I did some tube rolling for the 12AX7s in my preamp, and pretty quickly settled on NOS Voshkod 6N2P tubes matched by a reseller. They give me that full, warm, “blooming” sound I was looking for without sacrificing much treble detail.