tube upgrade for first sound


Has anyone been able to improve on the stock tubes in the First Sound preamps? I was thinking about trying the Russian 6H23. Any thoughts? thanks
84audio
Hello Guys

Please excuse my ignorance, but where can the above mentioned tubes be purchased? What would I ask for? I'm just getting into tubes so this is a whole new world for me. :-)

Thanks

Paul
Paul, Did you end up with a First Sound preamp? I ended up with a Supratek instead of the H-Cat. Bob
Hi Bob
First Sound it is! Don't have it yet. Should be acouple of weeks. I'm keeping my fingers crossed. :-) It meets all of the technical issues I have regarding DC leakage and all. I've tried 2 other tube pre's as well. I've been climbing the ladder. This is the end for me, no matter what. I hope this is "the one". :-) How is your Supratek?