Here is the top view of the Krell KSA 50 clone.

stats-
70 lbs
dual mono construction
each channel has:
softstart delay circuit
a 700 VA transformer,
4 pairs of MJ21193/94 transistors (250 W)
50 WPC class A.
128,000 uF capacitance.

corrected web link-- www.parttimeprojects.com/audio/diy/

The fan controller is an Aerogate II...or III, I forget.