mros, thanks for the feedback. Responses such as this will benefit everyone.
Most of my power tubes were bought when I had Elise and Euforia. I have gotten to know their sound signatures well over a 2 year period. gec 6as7g, bendix 6080wb, gec 6080, mullard 6080, 5998, 7236, rca 6as7g, svetlana 6H13c, rca 6080, ge 6as7ga, chatham 6520, chatham 6as7g. They all have their unique, distinctive tone. Do I have favourites? You bet.
Without comparing, I too could love and enjoy a pair of economical RCA 6080. However, like red wine, once you compare, you will discern that they differ more than just the different shades of the colour red.
You will also start to form opinions and pick your favourites. Not everyone is alike. So opinions will differ. Tubes will also sound their best for different genre of music and the tempo. I find it hard to categorically state that a gec 6as7g is better than a 5998. It really depends on what I listen to and the partnering source and headphones. One is silky smooth and enjoyable while the other is excitable, energetic and dynamic.
Amongst the power tubes, I have my clear favourites. They are gec 6as7g, bendix 6080wb, gec 6080 and 5998. Unfortunately these are also the most expensive.
Tubes will also sound different from one tube amp to another. I have heard the gec 6as7g on Euforia and La Figaro 339. When you've listen long enough, you will discern the subtle difference. Sometimes the difference is more than subtle.
It is for the above statement reason, that I am eager to hear those tubes in my forth coming Glenn OTL. I've tried 2 x c3g and 4 x 6BL7 in Elise and Euforia but those amps weren't designed with those tubes in mind. I've no doubt that a custom made and tuned Glenn OTL amp, will sound different and superior with 2 x c3g and 6 x 6BL7. Well I will find out for myself.
On the same token, I pioneered the use of 6 x EL3Ns in Elise. 2 as drivers and 4 as power tubes. These tubes in Elise that is not designed for it, sounded warm and lush, have an expansive soundstage and a very rewarding bass. I have no doubt that a very well designed Glenn EL3N amp with the option switch of pentode and triode, will sound very much different. Hence I'm very eager to hear a Glenn EL3N too.