Relationship of amplifier sound to transformer quality?

Two tube power amp designers/builders who say yes are Tim de Paravicini (EAR-Yoshino) and Roger Modjeski (Music Reference). Roger will personally hand wind you one for $1,000. Tim says he can tell you how an amp reproduces bass by looking at the transformer.

ptss---The DIY guys who build their own amps are the ones to ask about transformers. They all have their own personal favorite(s), but you see the name Magnequest a lot. rcprince is right, the Jadis transformers are really nice, but proprietary---you can't get one (without buying the whole amp!). Give Modjeski a call---he's pretty open about recommending stuff like that.

True for bass Don, but that compromises the highs. As in most things Hi-Fi, it's a balancing act. That's the art of transformer design.