On Thu, 9 Mar 2017 20:17:16 -0600, Foxs Mercantile
wrote:
On 3/9/2017 7:01 PM, wrote:
What type of capacitor would be the best match to replace
the old paper/wax caps in old tube gear?
Were you NOT paying attention previously when we ALL told
you to use the yellow plastic caps? 630 volt.
I WAS paying attention and I even contacted that seller and found out
they are made in China.
http://www.tuberadios.com/capacitors/
Or are you just being stubborn?
No, not being stubborn , I just dont want caps made in China. Not much
of anything made in China is a quality item. That seller has good prices
and a fair selection, but I still dont want China caps, which will
likely contain duds, and I'll end up replacing all of them in 5 years or
less, again.
And that site dont give enough info to translate to other sites. They
are just called "Axial Film Capacitors" on that site. When I look at
other sites, I see them sold with some sort of "poly" name, and I see
the word "film" used, as well as "foil". So, what do these compare to in
the words used to sell other brands?
That word "film" bothers me, anyhow. Just what the heck is this film? Is
it just some sprayed on metalic particles? The old paper caps contained
foil, which to me means something that looks like tin foil used in the
kitchen. Maybe I'm wrong, but if my radio or (whatever) was designed for
caps made with foil, I'd prefer to use caps with foil, and whatever
plastics they used to replace the paper. In other words, I want caps
that most closely mimic the original caps, except without the paper.
Paper dielectric capacitors are crap. They ALL need to be
replaced. Trying to "just replace the bad ones" is a fool's
errand. They're all bad or will fail after they're "back
in service" again.
Those paper caps may be crap now, but considering many of them lasted 50
years, they were not all crap, to last that long. I doubt any China made
caps will last even close to 50 years. I may be wrong, but based on
nearly all China products, I doubt any of them will last 5 years.
Everything made in China is just throw away short lived junk. Made to
fail one day after their warranty expires.
I have a Collins R-390A receiver on the bench. It's full of
paper capacitors. The IF module alone had 18 of them. They
have all been replaced.
"But it's Collins" and "Those were mil-spec" and and and
every other excuse for not changing them. Changing them made
a profound difference in how well the radio works.
I'm sure it did make a difference to the better, but for how long?
But rather that toss out my opinion, which is based on my overall
feelings about China products, you tell me how these caps have worked
for you. (assuming they are what you have used).
What precentage of them have been duds? If you have tested them, how
accurate are they? Have you had any fail? How long have you used them?
Will they really handle the max voltage they are rated as? How do they
perform under heat and other extremes? DId your Collins work as
designed, or did you have to re-align it or do any modifications because
the caps are not the "foil" type, and thus are not what the circuit was
made to use?
Sellers (of anything), always rate their goods at "Top Quality", but
advertising is mostly all lies. I want references from you, and anyone
else who is NOT connected to the seller.
These parts are bad. Anyone that tells you otherwise is
either lying to you or is delusional.
Although this is drifting from the topic, I just bought an old Sencor
Substitution box. It's for Resistance, Capacitors, (including lytics),
one silicone and one selenium diode, and a few other features. I took a
modern VOM with capacitor tester, and found all the paper/wax caps in
that box are still very accurate. However some of the lytics are not
even close. The resistors are all close too. Considering these parts
have seen little voltage and use, I see no reason to change any of the
small caps or the resistors. I do plan to change the electrolytics
though, because I know they deteriorate just from age, whether they are
used or not, because of the chemicals in them. (and my tests confirm
they are not even close to their rated UF values, some as much as 50%
off.
But I see no reason to change those small caps (.05 .001, etc). Not for
the brief times thay are used. and they are all very accurate in their
values.