My new AR3s!

[fast_eddie_72]

I saw an ad for a pair of AR3s several weeks ago for a fair price for their condition. I emailed the seller asking if I could come see them. I didn't hear anything until last night. He said he'd thought about restoring them but realized that he'd never get to it. I went over with my T Amp and iPod just to make sure they made some sound. I did a quick test to confirm that at least some of the drivers were working. They looked to be in good condition, but no grills. I figured I could come up with something, so I told him I'd take them.

As I was loading up he said "Oh, I have paperwork for those, too!". That was a neat bonus! A complete set for each speaker.

I'll have to go through the AR3 restoration guide here and get them working well. But just as they sit, they don't sound bad at all. I'm a little concerned about one of the mids, but the output doesn't seem to change at all when I mess with the pot, so I'm pretty sure the driver will be okay. Otherwise, I'm sure all the other drivers are working just fine. They don't even sound like the caps are too bad, though I think they will need to be replaced.

Really, pretty straightforward restoration, I think. I'm really happy to finally have a pair of 3s!

[rjr513]

Nice Find Fast_Eddie_72 and I think you'll be happy with the results of your future restoration project on these,also BTW you might want to send Kent a CSP member here a PM concerning some new grille material for your AR3's that we have found that is about as close to original that you'll find.

[genek]

If the mids are putting out at any volume, the lack of change is probably the pot. Any chance the seller might have bypassed them?

[fast_eddie_72]

Just looking at them, they've almost certainly never been opened. I did manage to get the mid in question to play a bit by jumping to the front lugs. Hard to get a connection there, but the driver is definitely working better than it is being allowed to show. I spent most of the evening listening to them with a little amp kit my son and I built. They're not perfect, but I did enjoy it. Can't wait to get them working well! But they likely will have to wait until some other projects wrap up. I tucked them in a corner of the family room, but I'm pretty sure when my wife gets home I'm in for an ear full.

[RoyC]

I'm a little concerned about one of the mids, but the output doesn't seem to change at all when I mess with the pot, so I'm pretty sure the driver will be okay. Otherwise, I'm sure all the other drivers are working just fine. They don't even sound like the caps are too bad, though I think they will need to be replaced.

They look like nice specimens...Congrats.

Regarding the mids...I've repaired 4 pairs of AR-3's in the past 6 months or so, and believe many AR-3 mids appear to be suffering from degradation of their domes' suspensions. Of the 8 mids in these 3's, as well as 4 used replacements, output was all over the place. The most common problem was reduced output due to stiffening suspension material. There were also obvious distortion issues associated with 2 of them.

If you have earlier 3's, you may have 600V oil filled caps. (I have never seen one of these not measure on the money.) If you have them, be sure to inspect the metal casing for leakage. They should not be confused with ordinary npe's. Folks pay big bucks for this type of capacitor today.

Roy

[fast_eddie_72]

I haven't worked on many speakers made before the mid 70s, and few that I wanted "right" more than these. So I'm taking a good bit of time to investigate before I do too much. I'll check out the caps and see what I have before I buy anything. It would be fantastic if all they needed was some work on the pots and some cosmetic restoration.

[RoyC]

I haven't worked on many speakers made before the mid 70s, and few that I wanted "right" more than these. So I'm taking a good bit of time to investigate before I do too much. I'll check out the caps and see what I have before I buy anything. It would be fantastic if all they needed was some work on the pots and some cosmetic restoration.

If it turns out that your mids are exhibiting the output issues I mentioned above, it would be easiest to convert your speakers to the last version of the AR-3. It used the later AR-3a type mid (fabric suspension instead of the white rubber compound) with a slight crossover modifcation. The schematic is in the CSP Library.

Roy

[JKent]

Hey Ed

Roy helped me a LOT with my AR-3 restoration (and many others), so listen to his advice! Those oil-filled caps are good. My AR-3s had the wax block capacitors so I replaced that with some nice Clarity Caps. If these speakers are "keepers" I recommend them. They're really high quality and not "too" expensive. Here's the 6uF: http://www.madisoundspeakerstore.com/px-cap-250vdc/claritycap-6.0-mfd-px-range-polypropylene-caps/

Another way to go would be to use a good cap like the Clarity for the 6uF but use surplus caps for the 24. You can get two 10uF plus two 2uF caps (per speaker) for under $2.00: http://www.madisoundspeakerstore.com/surplus-capacitors/

Here is the stepped attenuator I mentioned. Never used them but they seem to be good and perhaps a better choice than expensive open-back Ohmites: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7517

I should have all your grille-making parts within a month (AR logo, brass 3, original type grille material and frame), I "hope".

Those are great speakers. Good luck with them!

One last comment: As Roy pointed out, the mids may be on their last legs. IF that is the case you may want to go with AR-3a style mids. I bought a pair of AR-10pi mids for mine and I "think" they should work well in the AR-3 without any further modification. Check with Roy on this. As I mentioned, I eventually converted my 3s to 3a's but that involves a much more complex crossover and I personally think the original AR3 crossover sounded very good. Attached photo shows the AR-3 xo with Clarity Caps and Ohmite pots. I think the added inductor may be the xo mod Roy mentioned. Look here: http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/thoughts_on_ar-3_schematics/
Kent

PS: Roy was typing while I was and we're on the same page there.

[RoyC]

Just for the sake of clarification, implementing the later mid and associated AR crossover modification simply changes an earlier AR-3 to a later version, which had that mid as original equipment. It is not a conversion to an AR-3a, which as Kent pointed out, is a more complicated matter.

Roy

[fast_eddie_72]

Thanks guys. Feeling very confidant about getting these sorted with this kind of help available!

I'm fighting my urge to tear them apart and get to work until I have time to really concentrate on them and do it right after the holidays. But I am really enjoying them just as they are.

Thanks!

Ed

[fast_eddie_72]

Moved them over so I could hear them with a better amplifier. I did a little work with Rocky Mountain Lustre finish restorer. Love this stuff. They cleaned up pretty well. There were some paint splatters here and there so I did a little work with a toothbrush and soap. A couple of stubborn spots I had to use some acetone. But I got it all off. Really happy to see the condition. Not perfect, but really, pretty darn good.

You can see the damaged finish on the one. The other has a similar, but not as bad area. The flash makes it look much worse than it is, but it's there. Otherwise, not bad!

(edit) After listening for a few minutes, dog gone, they sound unbelievable for having done nothing at all to them. They must have the oil filled caps you mentioned, Roy. I've never heard a pair of unrestored speakers of this vintage, or even a good bit newer sound this good without a recap. Sorry for posting over and over. I'm really excited about these. I can't believe how good the bass is. I knew it would be good based on my LST-2s and the 5s I did for a friend, but these rival the 9s. It is almost imposible to believe that speakers this good existed 50 years ago. Well done, Edgar. Well done indeed.

[dynaco_dan]

Hi there

Thanks to a recent revelation by, Roy F Allison, we now know that the 1 3/8" dome tweeter was the same for the AR-3, AR-ST, AR-2A's and early AR-2AX speakers.

This is the only single tweeter used in all 4 and 8 ohm systems.

For decades we all thought that they were separate tweeter drivers with 4 and 8 ohm impedances.

This also kept the AR-3 tweeter at a much higher asking price due to it's assumed rarety.

Now we have more tweeters available to buy at a much more reasonable asking price.

Sad for all the buyer's of older and much higher priced tweeters.

[fast_eddie_72]

Welp.

After listening for a couple of days, the "new" wore off and it became clear to me that they, at least, needed caps. I pulled one woofer last night just to get a look inside and, indeed, no oil caps. Tonight I pulled the other woofer and was finally able to test all the drivers after the pots. Not good news. One midrange does seem to be totally dead. So I'll have to decide on what to do there. The other mid seems to be working well, but looking back at Roy's observations, may be prudent to replace them both. Found the late AR3 schematic in the library you mentioned. Easy enough mod and probably a better idea in the long run.

The other sort of odd thing - when I pulled the woofer last night, I made a note that the solder lug on the "flat" side was the positive lead. Tonight when I pulled the other one it was the opposite. I guess it's possible that that's right, but it seems odd. I'll have to test them with a battery to be sure. The one I pulled tonight looked to me like someone had be at it before. The solder to the speaker terminals wasn't done as well. So who knows. It's also the one with the dead mid, so maybe someone went in hoping to fix that.

Oh well. If it was easy, everyone would do it!

Thanks,

Ed

[fast_eddie_72]

You know, now that I look at them, the cage on the front of the mids doesn't look exactly the same. The brighter one is the working mid. I wonder if it has been replaced at some point in the past. Who knows?

[RoyC]

Ed,

It is not unusual for the woofer polarity to vary with these old beasts. The battery test will likely confirm the AR labels to be correct.

Other than the usual level control and capacitor issues, there are two other common problems relative to the AR-3. These concern the midrange (discussed above) and the woofer. While your woofers are out of the cabinets, make sure the areas where the surround and spider masonite rings are glued to the aluminum basket are OK. It is not uncommon for the rings to be fully or partially detached from the basket due to failure of the glue joints.

Roy

[fast_eddie_72]

Thanks, Roy. I'll go over the woofers carefully tomorrow and see how they're doing. Guess that glue is getting pretty old and brittle after all these years. Kinda like me! And I think you're right- the polarity had to be right. The bass was outstanding.

I spent a little time on the bad midrange and managed to get it removed without breaking the leads. Figured it would be good practice for the other one. I'm thinking I'll do the update and change them both out, but want to get the good one out in good shape so it could be used by someone else.

The Fluke tells the tale. Likely suspension issues aside, this mid is dead.

[fast_eddie_72]

So, does it matter if I use front wired mids or rear wired? Seems like it would be easy enough to run jumpers internally from the posts to the mid. Is there a reason not to do that? Obviously, front wired would look more original and I'd probably rather go that way if I can source the drivers somewhere.

[JKent]

Does not matter one bit. I prefer the rear wired myself but you can run jumpers from the rear terminals to the front of the baffle if you wish.

Kent

[RoyC]

Does not matter one bit. I prefer the rear wired myself but you can run jumpers from the rear terminals to the front of the baffle if you wish.

Kent

Here is the link to the AR-3 schematics in the Library.

http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/thoughts_on_ar-3_schematics/thoughts_on_ar-3_schematics.pdf

The one you would use with the later mid is in section "D" pertaining to 70,229+ serial numbers. Since you are replacing the caps, simply use a 30uf cap for the mid and a 6uf cap for the tweeter. Note that the additional inductor for the new mid is the same value (.4mh) as the one used in the woofer circuit.

Roy

[fast_eddie_72]

Thanks again Roy. That's making more sense now. I really need to try to set this aside for now (though I'm clearly having a hard time letting them alone). Just too much going on. I had to stare at that schematic entirely too long to figure out why I didn't have 16 ohm resistors in my speakers. I'll get back to them after the holidays when I'm (hopefully) less distracted. Though I may pull my "16 ohm resistors" and start cleaning them up. Several parts to source.

Kent, thank you as well! You guys have certainly been generous with your time and I sure haven't been going out of my way to understand anything very readily. I really appreciate the help.

Flying to Cincinnati on Monday. I'm hoping to sneak out of holiday festivities long enough to take a trip up to Parts Express. I think it would be fun to look around the showroom.

Happy Holidays everyone!

Ed

[fast_eddie_72]

Life has kept me plenty busy! But I finally turned some attention to the AR3s this weekend. I did get grills made with the help of JKent. Today I'm digging into crossovers and mids with the outstanding help of RoyC. I can't thank you guys enough. Glad to be bringing these classics back and you guys should both feel good knowing you had a hand in their revival!

Here's what I came up with for the crossovers. I think it should work out just fine. I tried to keep as much of the original wiring in place, and plan to leave the original cap mounted. I haven't mounted my crossover board yet, but plan to just attach it with a couple of dabs of hot glue.

I oriented the coil on end to reduce cross-talk with the other coil. I've made that modification in other speaker crossovers and had good results in the past. Coil is held in place with epoxy and the caps are in place with a general purpose clear adhesive. I wanted to be sure there was nothing lose to rattle in the cabinet.

[fast_eddie_72]

The yellow wire had a section of insulation stripped and was just wrapped around the terminal on the pot and soldered. I used that spot to add my own wire to go to the additional coil.

[fast_eddie_72]

One speaker together for a quick audition, and....

Everything seems to be in order! I did not take out the pots, which I know was a lazy move, but they seem to be in surprisingly good shape.

Well, so far it sounds great, but I've only been playing it for a minute. The bass is outstanding (no surprise) and I now seem to have mids and highs that are working right.

Going to take a break, but hope to get #2 together today as well!

[fast_eddie_72]

And the second together. They sound super! Really enjoying this! I have some new sealing putty on the way, so they'll be "naked" until I get that in. I think they're sealed reasonably well, but no point rushing at this point. I think I'll pull the pots out at some point too, so I don't want to wiggle the grills in place just yet, but I'm very happy with the progress I made this weekend.

[ligs]

Nice close-up pictures. I do have a question about the midranges. They look to me very much like those service replacements for AR 3a's, with 1.5 inch domes!