[AR-3st]

I also hope to receive help and valuable advice from CLS members on my project to build a "new" AR-3st.
I have a very good pair of tweeters around '75 year, purchased as spare parts in surplus, currently not used.
My idea is to recreate a new supertweeter (as done in the 60s by AR), with the difference of using the .75 "tweeter instead of the original phenolic dome tweeter.
The tweeters are visible in the first three photos, the next two photos show the canvas I will use on the speaker, donated by a grill of my Heathkit AS-2a (it is practically the same as the original AR, also compared to the photo below that show the original AR-3st).
The remaining photos show the original supertweeter and the vintage brochure (although the mounted tweeter will be different from the original design, I think the new AR-3st will look almost indistinguishable from the original).
The biggest problem for me is finding the value of the coil to cut the frequency, the measurements of the cabinet are easily detectable knowing the length of 11 1/2 "published on the brochure (if there is a member who is in possession of additional measurements or technical data it's welcome !!

Thanks Giorgio.

 

[AR-2t]

AR-2t is not a mistake, but it is an idea to improve the mid-high frequency of my AR2s.
At the moment I have connected in parallel a couple of AR-1MS to the older sisters AR2 (I have also turned the speaker upside down to have the 10 "woofer closer to the middle / high part given by the AR-1MS pair).
I disconnected the bridge connection that fed the original pair to eliminate the original tweeters.
As you can see from the attached photos, the AR2 pair is positioned above the AR2a pair, both are powered by a Philips RH 521 amplifier (30 wx 2 on 4 ohm the declared power of the amplifier, more than enough power to deliver a good sound output.)
How the AR2s sound with the additional "tweeter": noticeably improved the high frequency, the mid-range is very present, in comparison, for the same volume delivered, the AR2 AR-1MS complex, has mid and more sound pressure compared to AR2a (I suspect that the perceived sound seems to be about 3 db higher than the three-way sisters).
Very, very satisfying and a lot of improvement in distinguishing the musical instruments of the played songs.

I would like to have an advice to be able to insert a correct crossover filter (maybe just a coil?) To make the AR-1MS work as a medium / high unit (not as a fullrange speaker), removing the overlay of low frequencies, leaving the only AR2 woofer to deal with bass.
I understand little about electronics, I have no ability to design a correct crossover, I hope to receive valuable advice and help from authoritative and competent CLS members.

Thanks Giorgio

 

[Anatomy of a 200029-1 Tweeter]

3 hours ago, Pete B said:

Just to be sure I follow, are you saying to transfer the faceplate so that they are correct 

for whatever 4 ohm application you want to use them for?

Those are 4 ohm I take it?

Hi Pete, this is my "intuition", I can not know if the tweeters are 4 or 8 ohm (I live in Italy, the seller does not send to me and does not declare the resistance of the tweeters), but my thoughts are: 1) these are made in the USA not Tonegen and the construction and aesthetic dome / coil and output wires is identical to the AR10 / 11 tweeters.
2) the magnet according to my opinion and the visual comparison makes it identical to that of the noblest tweeters (in the AR10 / 11 tweeters the magnet is inserted in the plastic container, glued on it on the back, above then were placed transparent or black stickers , depending on the period for aesthetic reasons) also the subsequent series AR9, AR58 etc. (look at the holes for fixing the top flange of these tweeters)
3) Same procedure for adapting the complete tweeter in the plastic box of the AR3a and LST, also possible the front wired connection as originally (I'm not a technician, but you have ability to perform a correct crossover in this case!).
4) disassembling the dome / coil assembly, this could be a valid replacement with little work for all types of tweeters described above!
I repeat Pete that these are my intuitions, but in case of purchase of the tweeters at auction, with a small expense you could probably have 2 valid and original spare parts.
5) if the tweeters were 8 ohms, the AR loudspeakers that could benefit would also be in this case many: AR5, AR2ax, AR LST2 and many later

[AR94s in the house!]

Hi Sudhir, I have 4 woofers 200001 and at my multimeter they measure 4.7 and 5.0 ohm as you can see from the photos

[200003 AR 12" woofer vs 1210003-2A TNG 12" woofer]

8 hours ago, DavidR said:

What are your impressions between the two woofers?

Apart from the physical and aesthetic differences between the 2 woofers, there are also differences in the sound.
I'm not a technician, but according to me (I hope to describe well my feelings) the bass TNG is softer than AR, I also think it is slightly less present as total amount perceived during listening (the explanation is not the best, but I think there are other more qualified people to better describe the differences between the 2 types of woofers) ...

Giorgio

[200003 AR 12" woofer vs 1210003-2A TNG 12" woofer]

4 hours ago, ra.ra said:

HI Giorgio, those are great pics to show the subtle variations - - - it looks like there are minor differences in the magnet assemblies and the basket profiles and wiring terminals, but basically these drivers otherwise appear nearly identical. DavidR's question is what we all want to know, but I also wanted to mention that you misidentified the Tonegen woofer - - it should read part number 1210003 (-2A) - - - the "3" part is important since it correlates with the 12" woofer. 

Also, are those AR tweeters mounted on your wall next to the Jefferson Airplane album cover?

Thanks ra.ra, I corrected the title (I did not realize the omission of the identification number of the woofer TNG)
On the left wall there are 2 cones (fullrange) Lafayette circa '72, on the wall on the right 3 Philips cones

[Anatomy of a 200029-1 Tweeter]

On 1/1/2019 at 7:08 PM, Giorgio AR said:

In this moment, 2 of these tweeter in auction at 22,50 $, cost about 1/3 compared to other non-original replacements!

Now still missing 16 minutes to expire (unfortunately there is no sale in Italy, I would buy them !!)

[200003 AR 12" woofer vs 1210003-2A TNG 12" woofer]

I publish a very detailed visual comparison on the aesthetic differences between AR 12 "woofer and Tonegen 12 woofer

[Anatomy of a 200029-1 Tweeter]

In this moment, 2 of these tweeter in auction at 22,50 $, cost about 1/3 compared to other non-original replacements!

[Anatomy of a 200029-1 Tweeter]

Hi,

in my opinion, in addition to the problems of ferrofluid, I think I can suggest an excellent alternative substitute to the AR9 tweeter (visible in the photos below, taken from the usual auction site E..y)
in this case, replacing the complete magnet and dome unit.
Another option or use in my opinion (I hope that experts like Roy C or Frank M. or Tom T. will test this!), the second use that I believe can be done is the replacement of expensive AR10 / 11 200011-1 tweeters, probably disassembling the magnet from the plastic basketball and assembling the complete group 200054-0, otherwise replacing only the dome, coil and cables.
Last, and probably possible, this could also replace the tweeters of AR3 (same 2 modalities as AR10 / 11).
It's been a long time since I think of this tweeter as a possible substitute for dead AR tweeters.
I hope to have stimulated interest and to have indicated another way to restore the tweeter of our beloved AR
Giorgio