I experimented with the Mullard 3-3 SE EL84 amplifier circuit out of the Mullard Tube Circuits For Audio Amplifiers project book.
My breadboard circuit utilized 6V6 finals, 6SJ7 pentode driver stage and a tube rectifier - probably and EZ80 or something similar. This was one of my first experiments using a LOW DCR Hammond ICT recommended by Jeff Medwin aka Drlowmu.
No typical tube amp performance benchmarks were taken as I didn't have spectrum/distortion analyzer equipment at the time of construction.
Subjectively, I only had some relatively inefficient bookshelf speakers to evaluation this circuit but I remember that it sounded OK.
I might revisit this Mullard 3-3 circuit since the book has a some measurement data to help builders validate performance metrics.