Look at the Vox VT50gtr it uses a new tube 50 watts. Looks promising but I haven't heard one in person. Oh and a bit of @TV the Wired Turtle 's cork sniffery I did put a good gold lion 12ax7 in the hybrids and it did make a bit of a difference. Not sure it was enough to justify the cost so they both have the original 12ax7's in them so I can put the Gold lions in my little 5-15 watt amps. Some experimenting to do.