Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Graetz 4R-216 Electrostatic Tweeter Replacement
#1

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.
   
#2

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.
#3

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.
#4

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
#5

Yes, that last one should fit fine. (phit phine?) Thanks so much.
#6

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
#7

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




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM

[-]
Who's Online
There are currently no members online.

>