Gangtweeter,
What brand was the NOS Paper in Oil cap you used? Where did you
get them? I asked in a previous post to this thread about the sound quality of
the Russian KBG pio caps.
I've read of people considering the old motor run caps, although I wonder about the sound quality of those. I know there's boutique pio caps but they're too expensive.
I guess I'll just try the Russian PIO when I eventually find my W60's.
Cheers
Just look for any US-made, PCB-era oil caps. Motor runs are OK, but the key to look for is the age (You want something from the peak of the PCB era, basically the '50's to the mid '60's, give or take... The non-PCB ones apparently don't sound as good). Also, you want to keep track of the voltage (and you need to know the conversion ratio between "volts AC or VAC" and "volts DC or VDC"... I think AC is something like 2.272 bigger or something along those lines).
I put NOS 1000VDC Sprague oil caps (from the early to mid '60's) on the mid-woofers. l got REALLY-lucky with those. Sony6060 and Crestwood23 were helping me shop, and those happened to be up at a killer BIN. About as high-quality as a speaker like that would ever need. For the tweeters, Sony6060 found me a pair of 600VDC Sangamo oil caps. Both pairs were US-made and PCB-era, and that's what you look for.
Or if you want to go with the Russian ones and make sure they're the ones that say "KBG". Those are the ones that were custom-spec'd for the KGB exclusively. But check the voltage as well. You probably don't need more than 50-100VDC for an old Wharfedale crossover, but the higher the voltage rating, the better the construction quality. Just get as close as you can to the uF value the speaker needs, get the highest voltage-rating you can find and afford, and that's it. The value on mine wasn't perfect, but let me tell you, they sound GOOD. It completely-eliminated the polypropylene glare I was getting, plus it woke them up to the point of them sounding like new speakers, and mine had just been recapped 3 years ago. And Crestwood23 used Russian KBG's on the mids of his W90's and the same exact Sangamo ones that I put on my tweeters, and he's been thrilled with the results.
Just start looking on Fleabay for names like Sprague, Sangamo, G.E., Industrial Condenser, etc. There were so many different brands. You'll get the idea.