Layout Sheets show a "WIRE NUT"  (small print)  that could appear to indicate something attached to the chassis.  This IS NOT THE CASE. The wire nut secures the hot wire from the power cable to one of the primary wires of the power transformer. Note that the hot wire of the power cable (A.C. CORD) is black (or brown). The neutral or "common" wire is white (or blue). You may opt to use a piece of heat shrink tubing over a soldered connection. 

WY3 = 5Y3 for our purposes

6V6GT = 6V6 (GT = glass tube) 

25uF 50 volt bypass capacitors are supplied in place of 22uF 25 volt capacitors. There is no audible difference. 

Larger Capacitance Value (than customary) 450 Volt Filter Capacitors are supplied for improved filtering of ripple current. Ripple Current is anathema to good function and not conducive to good tone. 

5.1K  two or 3 watt dropping resistor on the power rail replaces 4.7K 2 watt.  Some of the vintage layout sheets show a 5.1K resistor in this spot. Not a significant modification.

The Polarity of filter caps and bypass caps is critical!  
The plus signs (+) were not printed on the 5F1 Champ Sheets. If it is not hand written on the sheet, turn the sheet over and inspect the 5E3 Layout Sheet. It shows the correct polarity of all caps where polarity is important. 

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