UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - My first valve radio project

Argus25 · 27th Dec 2016, 2:32 pm

For the low range pF capacitors (usually 3pF to 3000pF range), if you have to replace them, such as ones that get damaged ,fail, or removed by mistake, these are always better replaced with 500V silver mica types. These usually have a dark brown look. The better quality ones are the American mil spec types, if you use these you will never have any trouble again, especially in a domestic tube radio where the voltages are generally nowhere near 500v. Here is a typical one on UK ebay:

http://www.ebay.co.uk/itm/CAP-SILVER...wAAOxyaTxTPxin

There are some cheaper 330pF Sangamo ones that are also good on ebay. Last time I looked RS components also stocked a range of 500V silver mica caps which are very good. (any capacitors on the mains power side of the transformer need special ratings like X2 types)

Don't be upset with the occasional mistake along the radio restoration trail, by the time you have restored a few radios you will have mastered the art.

I would be cautious with the 330V electrolytics, since when the set hasn't warmed up the voltage could easily go to 300v x 1.4 , so 450V electrolytics might be better, but if the peak voltage is only 300V its probably ok.

27th Dec 2016, 2:32 pm	#90
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: My first valve radio project - Philips 462A For the low range pF capacitors (usually 3pF to 3000pF range), if you have to replace them, such as ones that get damaged ,fail, or removed by mistake, these are always better replaced with 500V silver mica types. These usually have a dark brown look. The better quality ones are the American mil spec types, if you use these you will never have any trouble again, especially in a domestic tube radio where the voltages are generally nowhere near 500v. Here is a typical one on UK ebay: http://www.ebay.co.uk/itm/CAP-SILVER...wAAOxyaTxTPxin There are some cheaper 330pF Sangamo ones that are also good on ebay. Last time I looked RS components also stocked a range of 500V silver mica caps which are very good. (any capacitors on the mains power side of the transformer need special ratings like X2 types) Don't be upset with the occasional mistake along the radio restoration trail, by the time you have restored a few radios you will have mastered the art. I would be cautious with the 330V electrolytics, since when the set hasn't warmed up the voltage could easily go to 300v x 1.4 , so 450V electrolytics might be better, but if the peak voltage is only 300V its probably ok. Last edited by Argus25; 27th Dec 2016 at 2:47 pm.