AR3a Speaker Upgrade - Advice?

[Guest]

In 1969 while in VietNam, through the Military Exchange System, i purchased a set of AR3a speakers. i used them for about 4 years, they developed a problem and i returned them to factory for repair. i believe the refurbish was complete, new woofer, midrange and tweeter as well as new cabinets. Some time to get them back, bought a new set of floor speakers. No neede, i tested the ar's and put them in the closet where they have been since, unused since circa 1974. In Sept my son took my mains with him to school in MIT, so i took the ar3's out for use. They seem to work fine, except the surrounds are rotten.

Local speaker repair folks say i should upgrade to "modern" tweeters and midrange while the refoam is being done. They also recommend new electrolytics. Hey, the ones in there have done no heavy lifting!

Not adverse to spending the money, to replace something not even yet broken in, but for all i know about the subject i could be replacing something that is better than what will be paying for.

For $1K a speaker for the repairs, maybe new set of speakers? Music taste is classical (violin) through bluegrass (fiddle) and everything in between. Driving equipment is Carver TFM 35.

Any advice/suggestions greatly appreciated.

BTW: Folks at www.radioera sent me over here, and what a fine website this is. We are very impressed with the site. Simple yet so very effective.

Thank you for letting me join and in advance for any advice.

john young aka Wakani@aol.com

[administrator]

After having begun the upgrade of a mismatched set of AR-3 and AR-3a, I would recommend just going with the surround replacement on the woofers. If your pots still work without much hassle, consider yourself lucky!

The only reason I can see for doing anything more extensive to the AR-3a's is if you are using them for digitally mastered (and digital source) material, electronic music, etc. It doesn't sound like you are.

You can always do the surround repair and leave them in your system for a while to see what you think.

Mark

[Carlspeak]

I recommend refoaming the woofers and replacing the caps. The caps are made with old technology. New designs utilizing metallized polypropylene film improve the sound greatly. As Mark said, if your pots are working okay your in good shape and you'll get the most bang for the buck doing the above.

I do refoaming and my prices are competitive. You can get replacement caps thru Lane Audio if you want. I can get you better ones for less money and will help you with replacing them.

Let me know if your interested in a quote.

Carl, The SpeakerDoctor

www.spkrdtr@worldnet.att.net

[tysontom]

From the description you give, your AR-3a's have barely seen the light of day, let alone any rough 30-year service. Probably a good re-foaming of the original woofers and inspection/cleaning the level controls is all that needs to be done. As for capacitors, there is really nothing wrong with the stock units. In my experience, I have never ever had to replace crossover components (other than level controls) in any AR loudspeaker that had been treated in a normal manner. Yes, one was struck by lightning, and part of the crossover and the woofer had to be replaced, as well as burned-out fiberglass in the enclosure, etc., but never under normal music-input signals. Unlike KLH and some other speaker brands, the caps in AR speakers usually hold up quite well over the years.

If you retrofit the midrange and tweeter drivers with something newer, you will no longer have an AR-3a, so you may as well go out buy a new pair of speakers and save all the hassle. On the other hand, the AR-3a -- as we all know -- was one of the best speakers ever, and 100% worth the effort to restore. In case you haven't noticed, I am a proponent of AR restoration, not AR redesign.

In my opinion, the best bet would be to purchase a surround kit for the 12-inch AR woofers, and repair the deteriorated (oxidized) foam surrounds yourself. You could also send the woofers out for repair, or you could buy brand-new replacement woofers. On the other hand, repairing the surrounds is not a difficult job, yet does require patience. Incidentally, while the woofer is out of the cabinet, you might also spray some "contact cleaner" in through the slots on the Pollock level controls, and wiggle the knobs back and forth quite a bit to clean the contacts. Depending upon the ambient relative humidity where the AR-3a's were stored, you may not need to do anything but twist the controls back and forth; if it was moist where they were stored, you may actually have to remove the controls and use a Dremel tool and "wire brush" the contacts, or use some very fine sandpaper (400- or 600-grit), and remove the tarnish/oxidation from the brass and german- silver contacts and wire. Put a little WD-40 on it once finished, and this will last for a pretty good period of time. Hopefully you will not need to do this degree of refurbishment.

Also, before doing anything, play some music (at relatively low levels due to the woofers' surround problem) with broad frequency content and listen with your ear close to each midrange and tweeter driver to determine the condition of the level controls. Rotate the controls back and forth and listen for dropouts. You might find that you don't need to do anything with the controls but wiggle them back and forth until the music flows through the tweeters.

Good luck with those AR-3a's, and let us know if we can help you further!

--Tom Tyson

[Steve F]

>From the description you give, your AR-3a's have barely seen the light of day, let alone any rough 30-year service. Probably a good re-foaming of the original woofers and inspection/cleaning the level controls is all that needs to be done. As for capacitors, there is really nothing wrong with the stock units. In my experience, I have never ever had to replace crossover components (other than level controls) in any AR loudspeaker that had been treated in a normal manner... Unlike KLH and some other speaker brands, the caps in AR speakers usually hold up quite well over the years.

>If you retrofit the midrange and tweeter drivers with something newer, you will no longer have an AR-3a, so you may as well go out buy a new pair of speakers and save all the hassle. On the other hand, the AR-3a -- as we all know -- was one of the best speakers ever, and 100% worth the effort to restore.

--Tom Tyson

As Tom points out, this is largely a philosophical question—is the goal to restore a classic or simply end up with a working pair of speakers? Most of us on this site regard the restoration and maintenance of classic old speakers to be a most entertaining and worthwhile goal. If that is your aim, then by all means follow Tom’s excellent advice and try to keep your 3a’s as close to original as possible. As I’ve said before in another thread, some of these old designs were better than their designers ever imagined, and fed with modern source material, driven with modern electronics, they’re capable of astoundingly good performance.

AR’s 1960’s-70’s design approach has stood the test of time. The principles of smooth, uniform power response at the listening position, extremely low bass harmonic distortion (performance still unsurpassed by virtually all of today’s speakers), wide dispersion for placement flexibility and non-critical listener seating positions, high power handling, high reliability, and incredible unit-to-unit consistency have made the older AR’s true classics. The AR-3, 3a, 11, LST, and 9 all embody these characteristics, with each succeeding generation or “family” of products benefiting from newer technology, newer materials, and improved manufacturing techniques.

Tinkering around with different drivers, blindly replacing arbitrary crossover components, etc. might be fun to a certain degree in and of itself. After all, this is a hobby and the only rule is to do what you find enjoyable. But the idea of restoring a timeless audio product like the AR-3a is extremely appealing, and to have a well-preserved set like yours, requiring minimal work, is a rare opportunity indeed.

Bring your 3a’s back to life as real 3a’s, and you’ll not only enjoy some wonderful, smooth, deep sound, but the unique satisfaction and pride of ownership that goes with owning an audio treasure. You can’t buy that feeling from a driver catalog or at the Super Electronics Mega Store down the street.

Steve F.

[charger3834]

I don't have a very strong technical background like Steve or Tom, but I have heard AR-3a's and I know what I hear.

It is extremely naive to think that an old design is always inferior to a contemporary one.

I used to own a 1970 Dodge Charger and I have a lot of respect for those designs. I currently own an LS1 powered 2002 Camaro and it will kill most of today's machinery, but I'm not crazy enough to go hunting HEMI's.

Some of the AR design characteristics that these guys are talking about are pretty amazing, and would most likely be compromized by a refit. The risk is high; who would want to compromise off axis performance, acoustic power response, smooth energy response and musical accuracy ? How the these "rebuilders" objectively test that the refited design is acousticaly correct and superior to the original?

Restore these classics !

[ar_pro]

No offense is intended!

The repair and restoration of classic Acoustic Research speakers is an important and much-discussed topic on this forum - the members' practical tips & techniques are a valuable resource, and the collective result of many years' experience. That said, I believe that there is a philosophical difference between the legitimate restoration of say, a 3a, and an "updating" of that design, using "improved" current-day components. There have been a number of recent posts that center on this topic, and it might be the right time to voice our various opinions regarding the issue of "restoration" vs. "updating". Here's my two cents:

1.) There is an inherent practical value to AR's best speaker systems AS THEY WERE DESIGNED & BUILT - including all of the various iterations of their top-of-the-line 12"-woofer 3-way systems, the LST, and the original 9. These were the standard-bearers, and can still be of REAL USE in a modern music system. There are many, many multi-thousand dollar loudspeakers designed & built using "modern" materials and methods that are inferior to two & three decade-old AR designs.

2.) As Tom Tyson has accurately stated, a modified AR3a is no longer an AR3a. Is this what anyone wants? Isn't the point of restoring these systems to bring them back to as close to original shape as possible? How many current loudspeaker designs will still have devoted followers in 30 years? My guess is very few.

3.) Swapping drivers & crossover components is an experiment, and not a forgone conclusion - simply stated, replacing working, vintage speaker components with "modern" devices does not guarantee an improvement upon the original. The statement that replacing in-spec, "old technology" capacitors would "improve the sound greatly" is not ipso facto true, and at best, would be a very difficult proposition to prove. There have been some superb letters regarding the problems faced with the arbitrary introduction of modern replacement parts into well-engineered vintage designs, and it seems that the act of effectively improving a loudspeaker by swapping drivers, caps, and inductors is a little more complicated than it would first appear. To the best of my knowledge, there have been no claims made regarding the "improvements" brought about by re-sizing the AR3a's cabinet...could it be because this would be a self-evidently dumb thing to do? Or is it because it would be a time-consuming, expensive, and difficult experiment to conduct...certainly a bit more involved than soldering in new capacitors!

4.) And finally, a confession: I've put spikes under my AR-9s. And I replaced the binding posts with rugged, metal types. And I got rid of the 32-gauge jumper wires, replacing them with buss bar type connections. I've made these easily-reversed modifications because I felt that this is something that, given access to the parts, AR would have originally done, and more importantly, because I believe that they better enable the AR-9 to live up to the original intent (underline "original" & "intent", please) of its designers.

[Guest]

Thanks so much for your input. Confirms my uninformed opinion. In particular like the 1970 Charger analogy, as i have resisted stuffing a small block v8 in my 1955 Austin Healey 100-4 for some 43 years that i have owned it!

Have a set of foam surrounds in hand and that begets another question. Seems that since the ar3a woofer cone edges are inclined, eg, not flat, i should install with roll down rather than roll up. The physical match of cone to surround seems much better that way. While at same time resistance to cone movement appears to be greater with roll down than up. Intuitive rather than appears.

Pots seem ok. Put low level variable audio generator into amp all all seems to be working.

Again, thanks you all for the wonderful response, and will let you know how the fellow with two left thumbs makes out!

jy

[tysontom]

"Roll outward-facing," not "roll inverted" a-la-KLH and Advent. Inverted surrounds were never used on AR's, and are more prone to interfere with the speaker basket on large cone excursions. Anyway, start with the cone-side first, and glue the surround to that, being careful to go around the periphery several times with your finger to insure bond and straightness. Yes, the surround is straight on the inner edge and the cone is angled inward -- no problem. Once set to the cone, glue the surround outer-edge to the frame masonite (never remove it), "bouncing" the cone gently (with your fingers arranged around the dust cap) up and down to center it properly, then go around the frame with your finger on the outer edge of the surround the same way, pressing down as you go around once you have "centered" the cone assembly. Do this carefully and patiently and the assembly will be as good as new, almost. Big thing is to make sure the cone is centered. You really don't need to take off the dust cover and shim the voice coil unless you just can't get it centered otherwise. Once finished, bounce the woofer up and down in free air to make sure that it does not rub.

--Tom Tyson

[Guest SteveG]

>" ... glue the surround outer-edge to the

>frame masonite (never remove it), "bouncing" the cone gently

>(with your fingers arranged around the dust cap) up and down

>to center it properly, then go around the frame with your

>finger on the outer edge of the surround the same way,

>pressing down as you go around once you have "centered" the

>cone assembly. >--Tom Tyson

Tom, Is this best done with speaker cone facing up? perhaps this was to obvious to mention, but thought I's ask. Also, is there any sdifference in quality of surround materials available?

SteveG

[Guest]

Thanks Tom. i appreciate your guidance.

As we speak am getting started. i have actually ordered three surrounds from three different sources. All are the same, glue is different. All caution about making sure you have a "downward slope on your surround to match cone" but all provided the same with the lip on an approximately 6 degree up slope. For us know nothings, it is cause for pause!

Will let you all know!

jy

[Guest]

Finished with refoaming pair of AR3a's.

Did not glue speaker to my ear!

Came out okay so far. i do not plan to quit my day job just yet, but i think speaker has been recycled.

Synopsis: Fabricated a jig to hold speaker cone up level with frame while attaching inside lip to cone. Used two round plastic rods, heat formed to give correct "lift". Actually used pair of chopsticks, slightly bent to conform with curve.

Thought i used not enough glue on first speaker, overcompensated and used too much on second. But ok.

Glue was more like contact cement, or it worked like contact cement.

Was surprised at this. Would "string out" like contact cement.

Would help if instructions included a para or two on mechanics of speaker, e.g., function of dust cap, mechanics of surround and etc.

Happy i did it, and much thanks to all for you great help and encouragement.

Gonna go do a pair of AR 8BX's belonging to significant other.

jy