Been thinking about adding 10 meters to this amp, it works great, input SWR on 10 meters is fine, no output, I didn't see it on the print, I downloaded the prints for the SB-220 and SB-221, there has to be a filter not passing the signal, I just didn't see it on the prints, I looked up the mods on 73 magazine, sure miss that, shows plate choke Barker & Williamson 801, Barker & Williamson filament choke FC-25A, and Barker % Williamson tank coil 195-3, I can find some choke coils that are close, will I have to wind the plate tank coil? Last I checked the wafer sections for the band switch were available to take this amp from 160 to 10 meters.