>>Outside, in a throw together box, listening to Miles Davis:
http://www.theairtightgarage.com/mq/theamp.jpg<<
not bad looking at all for a "throw together" box...
it's a good looking amp!!!
the dyna tranneys at rated power operate significantly below the knee of the core material that they used. gives them good magnetic headroom and they don't fall apart sonically at higher power levels as you have observed.
Mike