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
Cannot Adjust an IF Transformer’s cores
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM
Cannot Adjust an IF Transformer’s cores
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM
PT-6 antenna connections
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM
Cannot Adjust an IF Transformer’s cores
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM
PT-6 antenna connections
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4. Yes, pin 6 of the 7C6 is...RodB — 07:34 PM
bridkarl
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM
Cannot Adjust an IF Transformer’s cores
Joseph, now you are an engineer!!RodB — 06:37 PM
PT-6 antenna connections
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM
Cannot Adjust an IF Transformer’s cores
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM
PT-6 antenna connections
I seem to have lost my way on this PT-6. I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM

[-]
Who's Online
There are currently 3961 online users. [Complete List]
» 1 Member(s) | 3960 Guest(s)
Avatar

>