When I plugged it in, last night. I swapped and went to a pair of PSVANE ART series12AX7 in a just repaired C2500. 2 hours later I was impressed. They sounded better than my humpty dumpty pair of Blackburns. I didn’t try them in my C20 but WOW. I’m a Telefunken, Mullard Blackburn or certed BP RCAs guy.
These are a dynamic valve and very closely matched. That could be my supplier. Excellent matching on his part. He actually checks ALL his valves..
PSVANE ART series ++++ I’d like to try them in a power amp pre section.. I got a good feeling here.