100n 'x' cap - UK Vintage Radio Repair and Restoration Discussion Forum

kentplums · 3rd Apr 2014, 6:06 pm

Hi again
I have some of these - could I use as direct replacement of 0.1µf despite them being 'x's?
Cheers
R

G8HQP Dave · 3rd Apr 2014, 7:33 pm

Do you mean X i.e. mains rated? They should be OK. Just bear in mind that X caps, having been optimised for one purpose, might have compromised on other issues.

ricard · 4th Apr 2014, 8:51 am

I've regularly used 100n X caps as replacements for the hideous Rifa caps in old Tandberg tape recorders. The tend to have the same form factor (at least for machines that use PC boards), so they are basically a drop-in replacement, and can be found for nothing by pulling them out of old set-top box power supplies and equipment of similar size.

Although as Dave says X caps might not be optimized for Hi-Fi, they're still way better than the caps they are replacing in this case.

Maarten · 4th Apr 2014, 12:44 pm

Better, unless the X caps in question are (RIFA) paper caps...

kalee20 · 4th Apr 2014, 1:20 pm

Quote:

Originally Posted by ricard

I've regularly used 100n X caps... can be found for nothing by pulling them out of old set-top box power supplies and equipment of similar size.

I'd be very cautious of that. There are threads from people who have found that capacitance is markedly lower than what it should be. Not totally surprising, with the occasional high-voltage glitch on the mains, zapping a small area of the capacitor (which, in accordance with its X rating, fails safe).

Best test such salvaged capacitors. I'd be surprised if there is any evidence of leakage, but not at all surprised if it was nearly open-circuit.

kentplums · 4th Apr 2014, 2:01 pm

Quote:

Originally Posted by Maarten

Better, unless the X caps in question are (RIFA) paper caps...

Ooops - just read the truth about RIFA, which mine in fact are. Thanks to all.
There are still many for sale on ebay etc, so that's where mine will be going too...

Cheers
R

Herald1360 · 5th Apr 2014, 12:48 am

Caveat Emptor indeed.........

G8UWM-MildMartin · 5th Apr 2014, 4:58 am

Sounds a good solution to disposal of dubious yet sought-after items when quite good ones such as
http://www.rapidonline.com/Electroni...acitor-10-5784 can be had for 10p each.
Though if I had acquired a number of them considerably more cheaply than that and having a Megger to test them at 1kV or more and in the unlikely event of most passing, it could be a different story.

3rd Apr 2014, 6:06 pm	#1
kentplums Hexode Join Date: Nov 2012 Location: Limoges, Haute-Vienne, France. Posts: 280	100n 'x' cap Hi again I have some of these - could I use as direct replacement of 0.1µf despite them being 'x's? Cheers R

3rd Apr 2014, 7:33 pm	#2
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: 100n 'x' cap Do you mean X i.e. mains rated? They should be OK. Just bear in mind that X caps, having been optimised for one purpose, might have compromised on other issues.

4th Apr 2014, 8:51 am	#3
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: 100n 'x' cap I've regularly used 100n X caps as replacements for the hideous Rifa caps in old Tandberg tape recorders. The tend to have the same form factor (at least for machines that use PC boards), so they are basically a drop-in replacement, and can be found for nothing by pulling them out of old set-top box power supplies and equipment of similar size. Although as Dave says X caps might not be optimized for Hi-Fi, they're still way better than the caps they are replacing in this case.

4th Apr 2014, 12:44 pm	#4
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	Re: 100n 'x' cap Better, unless the X caps in question are (RIFA) paper caps...

5th Apr 2014, 12:48 am	#7
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: 100n 'x' cap Caveat Emptor indeed......... __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

5th Apr 2014, 4:58 am	#8
G8UWM-MildMartin Heptode Join Date: Jan 2004 Location: Stockport, Greater Manchester, UK. Posts: 827	Re: 100n 'x' cap Sounds a good solution to disposal of dubious yet sought-after items when quite good ones such as http://www.rapidonline.com/Electroni...acitor-10-5784 can be had for 10p each. Though if I had acquired a number of them considerably more cheaply than that and having a Megger to test them at 1kV or more and in the unlikely event of most passing, it could be a different story.