Hi Jim!When we have the next audio club meeting, I'll bring my amp and we'll swap out the Valve Art 2A3's with Electro-Harmonix 2A3's to hear the difference in those. If Akhilesh or Phil bring their Zen amp, you will also hear the difference in sound of it. Of course, that means you'll be hearing a different output transformer and circuit configuration, but still, you'll be able to hear a handful of tubes.
Wayne