Class x suppressor capacitor - UK Vintage Radio Repair and Restoration Discussion Forum

jbraes · 15th Feb 2006, 10:43 pm

(Note from archivist; although this thread refers to a specific make/model of radio, the advice given re class X mains filter caps applies generally ).

I am restoring a Stella ST239U radio and would like to replace the capacitor across the mains input with a class X. The service sheet, for some reason, does not show the value of C66 in the capacitor list. Can any of you smart radio wise cookies out there, tell me what value this capacitor should be?

paulsherwin · 15th Feb 2006, 10:51 pm

I don't have a circuit for this radio but the capacitor value isn't critical - you can use whatever you have in the junk box in the 0.01uF-0.1uF range. The smallest value should suppress modulation hum, and the largest value won't suppress the sort of mains borne crud produced by bad switch mode power supplies etc.

Best regards, Paul

Paul Stenning · 15th Feb 2006, 10:55 pm

I usually use 0.047uF. It's a typical value used and I don't want to keep several different Class X caps in stock.

15th Feb 2006, 10:43 pm	#1
jbraes Triode Join Date: Jan 2006 Location: Ullapool, Scotland Posts: 18	Class x suppressor capacitor (Note from archivist; although this thread refers to a specific make/model of radio, the advice given re class X mains filter caps applies generally ). I am restoring a Stella ST239U radio and would like to replace the capacitor across the mains input with a class X. The service sheet, for some reason, does not show the value of C66 in the capacitor list. Can any of you smart radio wise cookies out there, tell me what value this capacitor should be? Last edited by Darren-UK; 23rd Jul 2007 at 10:01 pm. Reason: Note added and title made more specific.

15th Feb 2006, 10:51 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Class x suppressor capacitor I don't have a circuit for this radio but the capacitor value isn't critical - you can use whatever you have in the junk box in the 0.01uF-0.1uF range. The smallest value should suppress modulation hum, and the largest value won't suppress the sort of mains borne crud produced by bad switch mode power supplies etc. Best regards, Paul

15th Feb 2006, 10:55 pm	#3
Paul Stenning Administrator Join Date: Dec 2002 Location: Cardiff Posts: 9,073	Re: Class x suppressor capacitor I usually use 0.047uF. It's a typical value used and I don't want to keep several different Class X caps in stock. __________________ Paul Stenning Forum Admin/Owner and BVWS Webmaster