> This is a solid state amplifier with a tube preamp stage No it isn't, if you check the schematics in the article you'll see that the tubes aren't biased prop

> This is a solid state amplifier with a tube preamp stage No it isn't, if you check the schematics in the article you'll see that the tubes aren't biased properly and are mostly disconnected. They can't amplify audio. It's not even a starved plate design (which wouldn't need the 6.3V filament voltage). The circuit is clever enough to stop amplifying as soon as one of the tubes is disconnected, so they're a glorified switch. Which IMO is worse than if the tubes were there only for asthetic purposes.