X2 capacitor - UK Vintage Radio Repair and Restoration Discussion Forum

inecik38 · 13th Apr 2020, 2:39 pm

Hi, I have a kaiser radio and I have repaired it before but I have replacemend thats capacitors with poliprplen capacitors.is this wrong replacement, must I replace with X2 cap.

paulsherwin · 13th Apr 2020, 2:41 pm

You only need to use an X2 cap where this is across the mains supply.

inecik38 · 13th Apr 2020, 2:57 pm

What happens If I use polipropilen capacitors.

paulsherwin · 13th Apr 2020, 3:21 pm

Polypropylene caps are OK where you have fitted them because they are not across the mains electricity supply. X2 caps are designed to survive voltage spikes and transients without failing short circuit.

JonSnell · 13th Apr 2020, 3:46 pm

Most manufacturers, current and older, fit disc ceramics in that position due to their excellent HF characteristics and efficiency at blocking the diode switching pulses. Polypropylene are more expensive but if you have them on hand, will work with no issues, voltage and value complying.

Graham G3ZVT · 13th Apr 2020, 3:50 pm

That circuit is crying out to have the other two diodes in the bridge shunted with their own 4.7nF's

Herald1360 · 13th Apr 2020, 10:44 pm

Maybe, but it's a selenium bridge rather than silicon and the two that are there will stop any HF ringing involving stray inductances in the mains transformer. If two more were necessary for the set's well being they would likely have been fitted conversely if none could have been got away with there probably wouldn't be any, regardless of good practice

13th Apr 2020, 2:39 pm	#1
inecik38 Pentode Join Date: Mar 2007 Location: Kayseri, Turkey. Posts: 124	X2 capacitor Hi, I have a kaiser radio and I have repaired it before but I have replacemend thats capacitors with poliprplen capacitors.is this wrong replacement, must I replace with X2 cap. Attached Thumbnails

13th Apr 2020, 2:41 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: X2 capacitor You only need to use an X2 cap where this is across the mains supply.

13th Apr 2020, 2:57 pm	#3
inecik38 Pentode Join Date: Mar 2007 Location: Kayseri, Turkey. Posts: 124	Re: X2 capacitor What happens If I use polipropilen capacitors.

13th Apr 2020, 3:21 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: X2 capacitor Polypropylene caps are OK where you have fitted them because they are not across the mains electricity supply. X2 caps are designed to survive voltage spikes and transients without failing short circuit.

13th Apr 2020, 3:46 pm	#5
JonSnell Hexode Join Date: Oct 2019 Location: Weymouth, Dorset, UK. Posts: 477	Re: X2 capacitor Most manufacturers, current and older, fit disc ceramics in that position due to their excellent HF characteristics and efficiency at blocking the diode switching pulses. Polypropylene are more expensive but if you have them on hand, will work with no issues, voltage and value complying.

13th Apr 2020, 3:50 pm	#6
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,724	Re: X2 capacitor That circuit is crying out to have the other two diodes in the bridge shunted with their own 4.7nF's __________________ -- Graham. G3ZVT

13th Apr 2020, 10:44 pm	#7
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: X2 capacitor Maybe, but it's a selenium bridge rather than silicon and the two that are there will stop any HF ringing involving stray inductances in the mains transformer. If two more were necessary for the set's well being they would likely have been fitted conversely if none could have been got away with there probably wouldn't be any, regardless of good practice __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O