My Freya (now the "vintage" version as it has a hotter output tube section which, alas, the newer versions have tamed somewhat) sounded quiet with the supplied "mystery" tubes, but they were boring so I moved on to new Tung Sols that look great! Also boring...so...NOS Sylvania "chrome domes" and RCAs have been doing the job real well and I’m not bored with them. My power amp is a single ended Had Firebottle HO (yes, a HO...says so right there) with a 6SN7GTB (NOS alleged Amperex) driver tube and I only mention that to point out the synergy of tube types, which means nothing. What does mean something is the fact that tubes are more fun than Class D will ever be...tubes can be looked at, burn yer fingers, and swapped out willy nilly. Class D can stay in my little Ampeg "Porta Flex" bass amp, flying above your head in phased array PA speakers, and in the future perhaps a better toaster, but not in my hifi or guitar amps...no no no. Less heat, efficient power...boring.
