Relationship of amplifier sound to transformer quality?

Thanks bdp24. Do you know which transformer manufacturers are most highly regarded?

Jap manufacturer Hashimito transformers compete just as great as Audio Note hand-wounded transformers.

One of the reasons Jadis electronics sound so good is their hand-wound transformers. 

If the transformer is not wrapped with low frequency high permeability mu metal sound quality will suffer. No two ways about it. The toxic effects of the induced magnetic field extends to everything within what, about a foot of the transformer? At least.

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.