Rek-0-kut Challenger TR-12H Caps replacement

[morrisjer]

Hi Guys,
I have a Rek-0-kut Challenger TR-12H and I would like to know where I can get caps for the Rek-0-kut (ROK). I am sure they don't make those nasty paper caps anymore and I guess they would have to be cross-referenced with other kinds. I have ordered a component tester and that would help identify what is what. Any help would be appreciated.

[mratx]

You actually can get replacements from some specialty mfgs if you really want to use that style of cap, but you can just replace them with other types that any electrical supply place (Mouser, Digikey, etc) will have. Just make sure to get the same value (although technically voltage rating can be the same or higher.) If the paper ones have a polarity marked on them you need to use electrolytics, if they don't you can use polypropylene (Cue debate on the audio qualities of different types of caps.). It's fairly common when redoing old amps to replace old foil/oil/paper caps and filter caps as a matter of course without even testing them, as they tend to go bad over time.

Mark

[emorritt]

Try this website:

https://www.justradios.com/capacitors.html

You can use metalized polyester film caps (orange dips) to replace old paper and oil electrolytics. They have no polarity, but what I do is mark the negative (striped) end in the circuit on the new cap with a sharpie, just in case someone starts making traditional high voltage electrolytics again, you'll know which direction to connect it in the circuit. They do sound better than traditional electrolytics.

[markrob]

The stripe marking on paper foil caps was not a polarity indication in the normal sense. It was placed there to indicate the location of the outside of the foil wrap. The idea being that it might provide some electrostatic shielding in certain instances. For a typical modern film cap, probably not a big deal they may not even have a "better" side as they are in many cases symmetrical.

[morrisjer]

Thanks so much guys and for the Website about capacitors!

[emorritt]

The stripe marking on paper foil caps was not a polarity indication in the normal sense. It was placed there to indicate the location of the outside of the foil wrap. The idea being that it might provide some electrostatic shielding in certain instances. For a typical modern film cap, probably not a big deal they may not even have a "better" side as they are in many cases symmetrical.

I do know from experience that if you install a polarized capacitor backwards in the circuit, it will explode...

[morrisjer]

Ok thanks.

[markrob]

What Emorrit is saying is very true for any electrolytic, but the foil paper caps are not that type. The foil caps are typically values less than 1ufd. So just take care when you dive in and you should be fine.

Mark

[mratx]

I think it depends on which caps he's referring to, as I've repaired a Rek O Kut amp (R8b I think) that had cardboard wrapped electrolytics. Which a person could think was a paper cap. Let your schematic be your guide! Note: I've also exploded a cap in my time, a supply rail tantalum. Went up like a firecracker!

[morrisjer]

Well thank you guys for being very informative. I aim to take care when I change things. I am glad to get this info and the schematic.
Jerry