Just scored a set of mint Philips 7581A tubes of eBay for super cheap, I can't believe it! Holy crap these are going to be nice in the Inspire SEP monoblocks.
Between the 7581A tubes today and the Amperex (Mullard) EL34 score this past Monday, it's been a good week.
I LOVE that I only need 2 output tubes for these amps, all my previous tube amps had 4 output tubes (at least!), so the MB 12 monoblocks give me a chance to explore some NOS tubes I'd never be able to afford as a quad. Love it!