Julius Futterman is an incredibly interesting man who engineered and patented the OTL (output transformer less) amplifier design. Mr. Futterman built around 100 amplifiers out of a small shop and his apartment in New York. He assembled everything by hand including the transformers. He actually sealed the transformers in a pot on his stove! There are many great articles written online about Julius, please take a little time and read about his work.
These amplifiers are honest Futterman H3AAs without any modifications. This set also includes a headphone amp built by Mr. Futterman for Stax electrostatic headphones.
These are currently not for sale, but it you have any questions about them please let me know. I can supply more pictures of the wiring if requested.