Mark IIA Tube Layout

Still getting acquainted with my IIA. Can anyone explain the tube layout of this amp (ie., what is each tube's function and location)? I've got a call into Mesa, but haven't heard back yet.

Also, my IIA has the original Mesa power tubes. Can anyone share opinions on these versus other tubes used? My main objective would be to increase clean headroom as much as possible...not so much gain as I usually play cleaner.

Thanks in advance as always.

Tim

this is from the original IIB maintenance and repair manual:




http://www.srl.utu.fi/~tke/MesaBoogie/

Acorkos....thank you. An absolute plethora of valuable information in the link you provided, too.