Beautiful air gap in signal transformer carrying dc

Watching the video interview on Allen Sides to Vintageking on the best studio equipment made by mankind, the UA610 preamp was mentioned. By briefly looking at a very low resolution reading and reading a comment on air gap used... It is very encouraging as Pleiades amplifiers are really naturally into this sort of thinking and doing. Class A operation (electrons flowing all the time) not just on the active device but on the output transformer too. Allen sides says the UA610 old version sounds so lifelike.