You may ask George Wright what he thinks, but I personally have found that, with the low-powered tube amps,cleaning up the power and or slapping on a power cord that costs as much as the amp does not make any difference to my ears. Those same things do make differences in the front end though. If I were going to invest in power for a tube amplifier, I'd invest in a dedicated circuit with an isolated ground and a good outlet. Just my opinion, of course. Worth all of .02 cents back in 77, while in the current economy I actually went into debt by sharing it with you!
Marco
Marco