I made a note about subbing 71A's for 183's in the Sparton Jr. In another forum someone said you'll need to change the bias resistor that goes from the center tap of the 5 volt filament winding from 1250 to 1800 ohms 2 or 5 watt. If you don't change this resistor, the 71As will exceed the design max plate dissipation. Credit for this goes to
Chuck D. KB9UMF over at
ARF:
http://antiqueradios.com/forums/view...e61baa8b0f2a2f