[Amps] SB-220 Replacement Tuning Cap

[Dennis W0JX via Amps]

Bill,
I have the replacement capacitor in my SB-220. I wouldn't call it heavy duty but the spacing is wider than the original SB-220 tuning capacitor. I have had no problems with the band switch arcing in my amplifier. However, my plate voltage seems to run a bit lower than some other SB-220s I have seen.

I highly recommend that you solve your arcing problem before you put in the replacement capacitor. File down and smooth out the plates in the original capacitor first using very fine crocus cloth. It may be that your parasitic suppressors need to be replaced. The original carbon suppressors age and change value over time. I replaced my suppressors with ones I found at Dayton a few years ago. I think they came from either an L4B or an L7. They are comprised of three, 120 ohm, 2 watt resistors in parallel. The coil is 3 1/2 turns of tinned bus wire wound around one of the resistors. My SB-220 is unconditionally stable on all bands, including the WARC bands.

73, Dennis W0JX