Thanks guys for all the help you provided with my radio’s 6x5g rectifier tubes.

Now I have another question.

I’m going to replace the large electrolytic capacitors in my radio’s power supply circuit. The radio I am working on is a Zenith 10s566 btw. I could replace the caps with generic electrolytic caps but in this case I’m inclined to replace the caps with metallized polypropylene film caps. Is there a downside to doing that other than the fact they cost a few dollars more?

:Thanks guys for all the help you provided with my radio’s 6x5g rectifier tubes.
:
:Now I have another question.
:
:I’m going to replace the large electrolytic capacitors in my radio’s power supply circuit. The radio I am working on is a Zenith 10s566 btw. I could replace the caps with generic electrolytic caps but in this case I’m inclined to replace the caps with metallized polypropylene film caps. Is there a downside to doing that other than the fact they cost a few dollars more?
:

I fail to see any benefit in doing so. Haven't looked at the schematic yet, but I suspect you will need quite a bunch of poly caps to replace any electros in a radio. Aside from cost and _size_, there is no benefit in doing so. Good electros should last quite a long time if you use the radio once in a while.

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I question whether film caps of the required rating are readily available. And they would be much more expensive than e-caps.

The physical size of film caps would be much larger. Maybe a problem to fit them in?

What would be the reason to use film caps?

Poly caps may last for many years. They certainly would outlast many older electrolytics. They cannot dry up, and often do not short. However, new electrolytics are usually made quite well. For instance, all of the electrolytics in my dad's 1972 Pioneer SX-440 are working fine, as they are in many other stereo amplifiers of similar design. Electrolytics have the problem of unforming if left dormant for a really long time. This can appear as a short. Such a problem can occur if the electrolytic isn't used for a period of say 20 or 30 years, possibly less. If used somewhat regularily, though, they stay formed. New electrolytics are much less likely to dry up. Many older ones have dried up, especially those which used natural rubber as a seal. Tar tends to crack, too, though many twist lock 'lytics are sealed with tar. I've seen many Zeniths and some other radios from the 1940s with electrolytics that still function well, so not all old electrolytics dry up. either. I have seen a lot of equipment from the 1950s and 1960s working fine with original 'lytics, too. I believe that many improvements were employed during this time.

I suggest that you stick with electrolytics, unless you want some really massive poly caps under the chassis. Electrolytics are pretty good, and they keep getting better. With regular use, they should last a long time (possibly 50 years or more).

Thomas