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Old November 26th 17, 10:49 AM posted to rec.audio.tubes
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Default What type of capacitor should I use?

On Thursday, March 9, 2017 at 5:03:00 PM UTC-8, wrote:
> What type of capacitor would be the best match to replace the old
> paper/wax caps in old tube gear?
>
> I am not referring to the electrolytics, those I know need to be
> electrolytic caps. I am referring to the inter stage caps, such as .01
> .05 .1, .005 and so on.....
>
> The object is to replace all the caps in an old tube radio, or any other
> tube stuff.
>
> Yes, I know this topic was sort of discussed a few weeks ago, and I
> recall hearing that any of them would work, but that does not really
> answer this question. Sure, they may all work, but what type would be
> the closest match to the original paper/wax types?
>
> From what I know, those caps were made from paper and a metal foil
> rolled up and coated with wax. So, what is the nearest similar type?
>
> From that last discussion, I know I left that thread sort of puzzled
> because all caps seem tp contain "poly" (which means plastic). I am
> thinking that what seems to be the closest would be whatever plastic
> replaces the paper, and a foil. From what I understand, some caps do not
> have a foil, but rather some sort of metallic material that is coated or
> sprayed on. Those are probably not what I would want to use, because
> they are not similar to the originals.
>
> I am fully aware that the voltage MUST be the same or higher and the uf
> must be close, such as .047 to replace .05. Also for tube circuits,
> axial leads are preferred.
>
> Then too, looking on ebay and other sources, I see a lot of very
> expensive caps which are intended for high end audio amps. For my needs,
> I will not pay $29.99 for one cap, and yes I have seen them cost that
> much.
>
> I am seeing some no-name cheap China caps selling for as little as 20
> cents each. While I like to save money, I'd really rather spend $1 each
> for something like the Orange Drops, which have been around a long time
> and seem to be good quality, despite the fact they dont come in axial
> form. But they generally can fit into most places.
>
> I will only be replacing those paper/wax caps and the electrolytics. I
> wont touch any mica or silver mica types, unless they appear to be bad
> (I will probably test them though).
>
> One that I do recall, are the so called Mylar, which I think were the
> first ones that were made to replace the old paper caps. I guess they
> now changed that name to something "poly" also.....
>
> What would you recommend or use?
> Web url's appreciated for lower cost AMERICAN made caps.
>
> One last thing, I found some cap assortments on ebay. 150 or 200 caps of
> assorted values, labeled as NOS (New old stock), but they are NOT the
> paper/wax kind. Since I have no spare caps, and just want an assortment
> on hand, I was thinking about buying one of those. I would NOT buy NOS
> electrolytics, but for the interstage types, I might consider this, just
> so I have an assortment of caps on hand..


Why don't you use some Paper In Oil caps. You can find russion PIO's on ebay at a reaqsonable price AND they work great.
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