Graetz 4R-216 Electrostatic Tweeter Replacement - Printable Version

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+--- Thread: Graetz 4R-216 Electrostatic Tweeter Replacement (/showthread.php?tid=22562)

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Graetz 4R-216 Electrostatic Tweeter Replacement - RodB - 06-11-2021

Hello all,

I've just started restoration on a RCA 5QR73PX (Graetz 4R-216 in disguise) that has a pair of electrostatic tweeters that don't seem to work; no sound from either.  I'm looking at replacing them with regular paper cone tweeters.  What I need is a plan on rewiring to the output transformer (diagram below).  I'm thinking that the separate secondary can be disconnected from the B+ and used for driving the tweeters and a crossover.  Otherwise, they can be connected to the main speaker through a 3 mfd crossover.
   

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - mikethedruid - 06-11-2021

Instead of buying paper cone tweeters, why not buy piezo tweeters and save yourself all the bother? You can find them at reasonable prices on ebay.

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - RodB - 06-11-2021

Hi Mike. I've considered that but all the ones I've seen have one inch openings. This has 2-1/4 inches so I would have to make an adapter. I'm keeping that as a plan B.

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - mikethedruid - 06-11-2021

Hi Rod,

A quick search on eBay found these, not exact, but could easily be mounted to the existing board with just some new screw holes...

here's one

and...
another choice
and...

and another

and this, which is even closer...

and still another

As the old saying goes, "Seek and ye shall find." I knew about this source for these because I was looking for some tweeters to use when I get around to building a cabinet for my Scott 800B

Hope this saves you some time and effort.



Mike

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - RodB - 06-12-2021

Yes, that last one should fit fine. (phit phine?) Thanks so much.

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - radiorich - 06-13-2021

Hello Rob,
I also Find Parts Express a great source for speakers and I added a tweeter to my General Electric Console it really improves the sound .
Sincerely Richard

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RE: Graetz 4R-216 Electrostatic Tweeter Replacement - Arran - 06-17-2021

Even if you replace them with something else the originals can usually be rebuilt so don't toss them. Apparently they have foam in them that goes rock hard so they will no longer tweet.
Regards
Arran

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