Tweeter Repair

[Guest SteveG]

Can the tweeters on 3a/LST or on 11/10pie be repaired? In an earlier post tom Tyson describes a procedure for repairing mids. Is the tweeter harder or easier? Is it practical tp try to repair. The problem I am talking about is no sound, presumable from a break in the internal wiring. Is theis the likely cause of a dead tweeter??

Thanks for help on this!!

Steve G

[Guest dogmeninreno]

Steven at Layne Audio says no. I am not sure if someone has a procedure but if they do, I have 37 of these little guys that were supposed to be good when I bought them. We all have been there huh? Good ol' eBay sellers (some) and their promises I guess. I'll be interested to see what responses you get. Dale in Reno.....

[tysontom]

>Can the tweeters on 3a/LST or on 11/10pie be repaired? In

>an earlier post tom Tyson describes a procedure for

>repairing mids. Is the tweeter harder or easier? Is it

>practical tp try to repair. The problem I am talking about

>is no sound, presumable from a break in the internal wiring.

> Is theis the likely cause of a dead tweeter??

>

>Thanks for help on this!!

>

>Steve G

Steve,

Always the first order of business with a speaker system itself is to isolate the tweeter from the crossover, testing for continuity to determine if the coil is open or if the lead wires have broken. In the pre-1975 AR speakers, tweeters were for the most part soldered (or "hard-wired") to the outside tweeter terminal strip. After 1975, AR began to regularly use back-wired drivers, with push-on wire tabs. In any event, at least one lead of the tweeter should be disconnected from the internal wiring, and then a continuity check can be made.

If a tweeter is determined to be "open," or have no continuity across the leads, then it is most likely that the tweeter has been burned out through thermal overload (likely the result of amplifier "clipping" or excessive power due to certain types of electronic or rock music). In in AR-3's, AR-2a's and pre-1970 AR-2ax's with aluminum-wire voice coils and lead-out wires, the aluminum wire can get fatigued and break into two pieces, thus opening the connection, even though the voice coil itself has integrity. With the AR-3a and AR-10/11 tweeters, the voice coil is copper with copper lead-out wires, and the likelihood of a break in this wire is extremely rare. I had it happen to me once, but I think it was a fluke. Therefore, if an AR-3a or AR-10/11 tweeter goes dark, it's most likely a thermal burnout.

One other thing can happen to the domes with foam in the top plate: under certain conditions, the dome can "pop" out of the gap and break a wire or damage the voice coil. This condition is more prevalent on the aluminum-wire, phenolic domes and not the later domes. It never happens on the AR-10/11 domes.

Assuming that the tweeter has definitely been tested and found to be open (i.e., "burned out"), you can pretty much give up on the idea of repairing it. Practically no one has the skill, equipment, let alone patience to attempt to rebuild a dome tweeter. However, a year or so ago *AudioXpress* magazine (erstwhile *Speaker Builder*) published a series of articles written by T. D. Yeago, an individual who -- believe it or not -- completely rebuilt and re-wound the voice coils of the woofers, mid-range and high-frequency drivers of a pair of AR-3a's. There is no way of knowing how many hundreds of man-hours he expended on this project -- with virtually no test equipment to validate his experiment -- only to have less-than-favorable results in the end. It was a great science project, but it was another classic example of a beautiful hypothesis slain by an ugly fact.

The easiest, fastest and cheapest way to take care of a bonafide burned-out tweeter is to find another one on eBay, and they are out there all the time. Good luck!

--Tom Tyson

[stan461]

With respect to the 6 part article in "Speaker Builder" - there was a section in the series where Mr. Yaego loaned out the Ar3a's to a friend and he reported back nothing but praise for the rebuilt speakers. Actually he was gushing. Nowhere have I read that this project had "less than desirable results".

Maybe you know him ppersonally (Yaego) or have listened to his rebuilt AR3a's. Or maybe I missed something in the series. Could you please explain?

I am considering rebuilding one of the pairs of AR3a's that I own from top to bottom. The series by Mr. Yaego would be a nice guideline. I don't want to waste time and yet I don't want to abandon a project due to miss-information.

[Guest SteveG]

Wow Dale!!! 37 bad tweeters?? I have one that was known to be bad when I got it so I cannot complain.

Sounds like repair is somewhere between impossible and impractical. Thanks for info Tom. Ebay purchase sounds good, but as Dale points out, potentially disappointing.

Can anyone tell me what is available in the aftermarket as new replacements, like from ABTech or Layne? Are these more like the 3a or the 11 tweeters? Do they look and function exactly like either of these?

As for Ebay, I see 3a black paper dome tweeters fairly often, but seldom the type in the 11, with the cloth dome. I don't think I have ever seen the yellow/gold dome tweeter of the 10pi on ebay. Does anyone know of availability of 11/10pi replacements?

Thanks

SteveG

[tysontom]

>With respect to the 6 part article in "Speaker Builder" -

>there was a section in the series where Mr. Yaego loaned out

>the Ar3a's to a friend and he reported back nothing but

>praise for the rebuilt speakers. Actually he was gushing.

>Nowhere have I read that this project had "less than

>desirable results".

>

Well, first of all, I was afraid that someone might take offense to my statements and my opinions about Yeago's efforts. I actually corresponded with Yeago at great length, and we became well acquainted during those discourses; in addition, I thought Yeago was a good writer, describing his project well. Moreover, I gained respect for him and thought he did a good job fabricating the re-designed AR-3a's. As for Yeago's friend reporting back to him with "nothing but praise for the rebuilt speakers," I put practically no credence in that statement, even though that friend might or might not be an expert listener. As you probably must know, evaluating loudspeaker quality by listening is a totally subjective experience, and as they say, "one man's meat is another man's poison." Had a dozen knowledgeable audiophiles listened to those rebuilt AR-3a's compared side-by-side to original AR-3a's, and stated that the sound was superior, I would sit up and take notice. Or had a well-known and respected equipment reviewer from one of the audio magazines evaluated these speakers positively, I would have concluded that something significant did occur. But that did not happen. Yeago's project was remarkable in what he accomplished, but the speaker was not a step forward in sound quality. When Joe D'Appolito measured the speakers, I think the results were okay but not outstanding. There were problems. And what this tells me is that a single individual out there is pretty hard-pressed to go out and completely redesign a speaker system without extensive test equipment and engineering know-how. Speaker-building is part "art," certainly, but it is mostly science. Even large speaker companies, with millions invested in engineers, test equipment and test chambers and such, still struggle to get it right.

>Maybe you know him ppersonally (Yaego) or have listened to

>his rebuilt AR3a's. Or maybe I missed something in the

>series. Could you please explain?

>

I neither heard the rebuilt AR-3a's that he built nor do I know Yeago personally, even though we became acquainted through our correspondence. That really doesn't have anything to do with my perception of his project. My complaint was that his project was an exercize in detailed speaker-driver reconstruction, wiring voice coils, and re-designing magnet structures. If you have the desire, time and energy to do that, by all means go for it. I am not trying to tell you not to do it.

>I am considering rebuilding one of the pairs of AR3a's that

>I own from top to bottom. The series by Mr. Yaego would be a

>nice guideline. I don't want to waste time and yet I don't

>want to abandon a project due to miss-information.

>

The AR-3a (designed by Roy Allison, assisted by a large engineering staff in arguably the best loudspeaker-testing facility in the world at the time) was one of the finest loudspeaker designs ever produced. It certainly is far from perfect. It has flaws. But it still is an excellent speaker, even by today's standards. It was a quantitative "standard" of the day, and was accepted as such. Acoustic Research extensively measured and documented the performance of that speaker, and the critical review at the time reflected its superior design. My feeling on the subject is that the AR-3a is worth refurbishing to its original condition, and you will be rewarded by your efforts accordingly. Besides, when you decide to sell them, they will be worth much more than a highly "modified" AR-3a.

Am I too much of a purist? Probably so.

--Tom Tyson

[Guest dogmeninreno]

I have bought several replacement tweeters from Steve at Layne. One style looks like the backwired AR type but has a foam diffuser on the face. The resistance is not the same as the old 4 ohm units and measures 7-8 ohms. They sound good and as Steve points out, they are probably a better tweeter. Also they are a cloth dome type. I have also bought several of another style of tweeter that Steve recommends and he sends a mounting kit with them and they fit right in the old opening. I have not tried these yet. Dale in Reno.....

[Guest SteveG]

So the first type sounds like it would look like an AR 11 tweeter, but for the "foam diffuser". Does this diffuser have roughly the appearance of that on the AR9??

Also, does the higher impedance have any significant effect on overall system response??

Thanks SteveG