ratbagp wrote:
I was pondering doing B+ with cells in series and filaments with cells in parallel rather than doing an inverter. There had to have been a lot of tubes that were designed for lower B+ voltages.
ray
Actually there were. Portable radios (if you want to give credit to their portability) used tubes that had low B+ requirements. But there is no guarantee that those tubes would suit your audiophile purposes. Just one example would be the 12AE6A triode, running on a B+ of 36V. Also automobile radios way back when had tubes. My Dad's 1955 Dodge had an awesome tube radio using 6V6s in push-pull. It got the B+ from a multi-vibrator that stepped up the 6-volt system. Since the tubes had 6-volt filaments it was natural fit.