What really drove me to build this 6EM7 amp was an idea about amplifier layout. Looking back at most of my tube designs, and most of those on the internet, revealed a very typical pattern.
Amplifiers tended to be flat chassis with tubes and transformers above and electronics below. From a historical perspective this makes perfect sense. Metal chassis were built this way to facilitate packaging and assembly. When people started to make tube amplifiers again, they just removed the upper case and built in the same way.
For more detail: 6EM7 Single-Ended Triode (SET) Vertical Amplifier
