12AX7 tubes for Counterpoint NP400


I have a Counterpoint NP400 hybrid amp (200x2 into 8 ohms), which was recently given an "ultimate" ugrade by the amp's designer, Michael Elliot. I am kind of new to tubes, but am hoping to play around with some different tubes. Any suggestions for good (great) tubes to try out. Are there any concerns with various tubes I need to be aware of? Can I just drop them in, or do I need to rebias the amp? Any advice would be greatly appreciated. Thanks
alruhl

Showing 1 response by david99

I have 12ax7 in my phono stage.The sovtek Lps is a quiet tube but a little bright.I had them but bought Telefunkens which are even quieter and sound MUCH better.I bought 2 from Kevin Deal @ upscale audio.$35 each.No you only bias ouput tubes 6550,EL-34 etc.