AR 4s

[Horswispr]

Hey, Everyone. I'm looking for any wisdom you can share with me about AR 4s (I believe these are not 4xs or any other more recent models). I recently came up with a pair of AR4 speakers in BEAUTIFUL cosmetic condition but with several drivers that probably need replacement.

Is it worth it to try and find replacement drivers? I'm quite sure the originals are hard to find.

I do have an extra pair of Dynaco A-25 tweeters that I could use (I'd have to drill new screw holes, but I think they'd fit otherwise), but I recall hearing that the AR 4 had an unusually low crossover point, leading to tweeter burnout. Would I be risking my Dynaco tweeters if I dropped them in there and made a mix and match speaker just for fun? I don't want to risk my Dynaco tweeters since I work mostly with Dynaco speakers.

The woofers are replacements that the original owner said he got from the Sound Well in Berkeley CA many years ago. Unfortunately, they have foam surrounds and one of them has a hole/gap and is rotting a bit. I don't know if it's severe enough to ruin the sound short-term (I haven't hooked 'em up at home yet), but longer term, I'd rather have intact woofers.

Any suggestions about what to do with these?

Thanks!

[dynaco_dan]

Hi there;

Please post a closeup photo of the back, front and if possible the crossover.

From that, we will try to give you our best advice, before you do anything further, in repair/replacement.

Good luck.

[Horswispr]

Thanks, Vern!

It will take awhile, as I still use my old Olympus 35mm camera, but I will do so.

This is really funny: I'm actually listening to the speakers (local classical station) as I write. Both tweeters are out but the woofers sound good, even with the minor tear in the one surround. As is, these would be fine for a non-audiophile who likes listening to background music. But more importantly, I actually have a single Dynaco A-25 behind them, firing sideways and hooked up in a Hafler circuit (plays the difference between the two channels, as you probably know), and the sound is really cool! The net effect with the tweeterless ARs and the single Dynaco in a Hafler circuit is of an extremely over-damped concert hall, with the sound coming from behind the speakers and the highs very subtlely presented. I actually like it!

This "laid back" and deep effect is more or less what my Kloss-designed Cambridge Soundworks Towers try to achieve (with better high frequency extension, of course).

Makes me wonder if I could design an inexpensive system that achieves this kind of sound for those who abhor the "in-your-face" presentation of many contemporary speakers.

[Horswispr]

Vern--A more general question: Is there some kind of adhesive I can spray on a dying surround--at least the part where the tear is---that won't dissolve the surround and will temporarily "fix" a tear? I see the broken "flap" moving as the air from the enclosure hits it. I assume my Crazy Glue would dissolve it and my wood glue would be of no help. Thanks--C

[dynaco_dan]

Hi again;

Go ahead with you vision.

Henry Kloss started out with Edgar Villchur and an idea.

Look what we have today.

There is lots of inventions and ideas for us to persue, as time goes along.

The Dynaco quadapter, was an example of sheer genius, simple and effective.

Actually, just using the single resistor works well.

Just because we know what we know today, doesn't mean that you can't come up with a new approach and solution to an old problem.

Man has come along ways in the first millenium, who knows what will be discovered just around the next corner.

One does not need to be rich or supremely educated to discover something new, just rich in ideas and confidance and be given support.

You, with your idea, may be the next Henry Kloss.

Good luck.

[Horswispr]

Thanks for the encouragement, Vern. Who knows? The good folks at the Sound Well in Berkeley informed me that the A-25 tweeters would probably work well, so maybe I'll give that a try, just to see what it sounds like. Let me know if you know of any adhesive I can use to patch up the surrounds until I decide what to do long-term.

Thx!

--C

[dynaco_dan]

Hi again;

Sorry but I don't know of a space patch for the foam.

On ebay surround kits go for about the $15 - 20.00 range with 2 surrounds, shims (most techies use none and just float the cone into place) instructions and glue.

If you haul those two enclosures into a shop, expect maybe $35.00 +/-each to re-foam each.

If you take the woofers only in, maybe $25.00 +/-.

My first re-surround 12" woofer took me about 1 1/2 hours and the second about 10 minutes, that is just the surround re & re, not removing and re-installing the drivers.

Until you re-foam them it is best not use them, sorry.

As far as a Dynaco tweeter goes, I would try for a pair of AR-4x tweeters on ebay, usually around $15.00 - $25.00 a pair used.

Good luck.

[JKent]

It's very likely your tweeters are not dead, but the pots are all cruddy and need to be cleaned. Search here for info on cleaning them. You may want to replace the capacitors while you're at it--easy to do. As for the woofers, these often come up for sale on ebay. People "part out" old AR speakers. A heinous crime, but if you need a couple of woofers it might be worth it, especially since you are not sure about the pedigree of the replacements.

just my $.02

[charger3834]

With all due respect to the interesting ideas here, the AR-4 is a well designed historic speaker, why not try to rebuild it properly

First, lets try and identify what model it is; the AR-4 or AR-4x.

If it is an AR-4 (1964-1965), it's tweeter will be the 3.5" CTS built cone unit. It is covered by fiberglass and steel mesh. This is the same unit as in the AR-2x and AR-2ax. It should measure 6.5 ohms DCR. The pots should be cleaned first, I doubt your drivers are blown. The corosion must be removed, then they can be coated in dielectric grease and reassembled. The AR-4 system operates with a 2000 Hz crossover. Original style woofers should be located.

good luck.

[charger3834]

Vern has a good idea as well, these could be converted to AR-4x's. I would make sure all the other variables are controlled as well. The inductor coils, capacitor values, drivers and stuffing amounts should all be correct to a specific spec. Pick your poison AR-4 or AR-4x. This is really the only way to ensure you are building an accurate/neutral musical reproducer.

[JKent]

>With all due respect to the interesting ideas here, the AR-4

>is a well designed historic speaker, why not try to rebuild it

>properly

With all due respect to you, Brad, isn't that exactly what I suggested?

The tweeters are probably fine. The pots should be cleaned properly. Some advocate replacing the caps (I'm in that camp) others say "if it ain't broke don't fix it." The replacement woofers should probably be scrapped and originals found to put in their place.

[charger3834]

>>With all due respect to the interesting ideas here, the

>AR-4

>>is a well designed historic speaker, why not try to

>rebuild it

>>properly

>

>With all due respect to you, Bret, isn't that exactly what I

>suggested?

>The tweeters are probably fine. The pots should be cleaned

>properly. Some advocate replacing the caps (I'm in that camp)

>others say "if it ain't broke don't fix it." The

>replacement woofers should probably be scrapped and originals

>found to put in their place.

Absolutly, that is indeed what you stated. That comment was in response to the idea of installing dynaco tweeters.

[Horswispr]

If I installed Dynaco tweeters, it would only be temporary, just to see what they sound like. I have a >100 wpc B&K 202 driving whatever I hook up, yet I listen at low volume, so I'm not going to blow anything up. But if there's an opportunity to create something nice and authentic here, I should take advantage of it. The cabinets are pristine, and I have finished them well, honoring the original look (the sides are a tad coarse, but with nice grain) while restoring the wood to a nice glow. I'll move slowly re: installing new drivers or other components. Thanks for all the comments!

--C

[JKent]

I'll bet you a nickel there is nothing wrong with your tweeters. Save the Dynacos for another project and just clean up your pots. I'm sending an email with instructions (thanks to fellow forum members) and photos (hope you have broadband) ;-)

[Horswispr]

Thanks for all the comments, folks! I finally figured out these are AR4xs. I haven't taken any action yet re: replacing drivers. But I couldn't get the tweeters working just by twisting the pots. --C

[dynaco_dan]

Hi there;

Have you made any progress yet?

If one was to buy a used AR-4 - 4X woofer, I would make a note of the cone style and whether it has foam or cloth surrounds.

Some were smooth, some had circlular rings, some even had swirles of a compound to reduce cone cry, or resonances.

Someone with more knowledge may translate that information better than I can.

Because of the foam rot problem, I prefer the 8" woofers with cloth surrounds.

The 4X tweeter, has, to my knowledge, only one version.

The AR-4 8 ohm tweeter, which is also the AR-2AX mid-range driver.

There was at least one variant of this one, there were two resistors used for added impedance matching, in the AR-2AX version.

This would not be a direct insertion into an AR-4X cabinet, without bypassing the resistors.

I do not know that impedance but, in reading here, it was to better match the woofer used during some particular version transition.

Good luck.