[Amps] SB220 160 Mod

[Dennis W0JX]

Mike,  before you do your mod check out Rich Measures, AG6K website. He has a great modification for the SB-220 to 160. You do not have to change or add to the filament choke. You can "tune" it to 160, creating a high impedance, by using the proper capacitor at the cathode side of the input pi. A large RFC like the National is also not necessary. Rich shows how to add the extra inductance wiith a smaller choke. Vacuum relays are use to switch in the high power plate padder and load cap. A toroid coil is best used in the pi out.
 
With the proper line voltage, you can get up to 1200 watts out with about 120 watts of drive.
 
73, Dennis W0JX/8