New member with some AR-3 questions

[xbartx]

New member here, as I picked up a really nice pair of AR-3's last weekend along with a super clean early vintage Fisher receiver and a newer Sony CD player and tape deck.

I bought them untested, during the frenzy of an estate sale. They were in excellent cosmetic shape and all for $65, I couldn't pass on them.

I opened up one of the speakers, that I could hear had issues. The voice coil on the tweeter had popped off and one of the leads had broke right at the dome.

Here are my first questions as I'm sure I'll have more as I progress.

I've spent the last week gleaning info on the AR-3 and noticed a couple mentions that the AR-3 is a more difficult rebuild than the AR-3a,

I never came across a explanation as what made it more difficult?

As I search for a replacement tweeter on the popular auction site, The tweeter I see that looks most like mine is listed as for the AR-2ax?

-Brad

[genek]

Offhand I can't recall anyone saying the 3 is more difficult to rebuild than the 3a, but I've never been inside one.

The 3 and early model 2a/2ax used the same red dome tweeter and the drivers are interchangeable. The later 3a and 2ax/5 used smaller black dome tweeters that look the same but are different impedances.

[tysontom]

New member here, as I picked up a really nice pair of AR-3's last weekend along with a super clean early vintage Fisher receiver and a newer Sony CD player and tape deck.

I bought them untested, during the frenzy of an estate sale. They were in excellent cosmetic shape and all for $65, I couldn't pass on them.

I opened up one of the speakers, that I could hear had issues. The voice coil on the tweeter had popped off and one of the leads had broke right at the dome.

Here are my first questions as I'm sure I'll have more as I progress.

I've spent the last week gleaning info on the AR-3 and noticed a couple mentions that the AR-3 is a more difficult rebuild than the AR-3a,

I never came across a explanation as what made it more difficult?

As I search for a replacement tweeter on the popular auction site, The tweeter I see that looks most like mine is listed as for the AR-2ax?

-Brad

Brad,

If you go back through all the posts about the AR-3, you will find references to the problems that you might encounter during restoration or repair of this fine speaker. From the picture, I can see that your tweeter has a "popped" dome, a problem that is not particularly uncommon with the AR-3 1⅜-inch tweeter. There is a fiberglass damping pad under the dome which applies a certain amount of positive pressure under the dome at all times, thus eventually causing the foam suspension to give way on some tweeters. There is no repair for this problem. You can "fix" the issue and make the tweeter operate again, but the tweeter will never sound exactly right. Therefore, you should to go out on eBay or elsewhere and find an AR-3 tweeter and replace it.

The first big issue with the AR-3 is removing the grill-panel assembly without damaging the frame (most were made of molded plastic) or causing the grill material to sag. The other big issue with the AR-3 (not present in the newer AR-3a) was the use of aluminum wire for the midrange and tweeter lead-out wires leading to the tweeter-terminal-strip on the front of the speaker baffle between the tweeters. The AR-3 midrange and tweeter used massive Alnico magnets (9 lbs. 1.0 ounce structure on the early version midrange and 3.0 lbs on the tweeter) with free-standing aluminum voice coils wound without a former or "bobbin." This "formerless" voice coil was attached to the phenolic dome, suspended in the gap by the foam material and sealed by clear butyl rubber or silicone gel. This construction method resulted in drivers with very low mass and high magnetic damping, and the tweeters had very flat on- and off-axis frequency response and exceptional, "electrostatic-like" transient-response performance. When repair or replacement becomes necessary, the job is significantly more difficult (by a factor of 2 or 3 IMO) than with the copper-wire AR-3a. You should use Alumisol aluminum solder for best results, or a method of attaching the aluminum wire to copper wire by using a lug connector. Crossover capacitors aren't always defective, especially the oil-filled versions on the very early models, but the capacitors should be checked if possible. Crossover coils rarely fail unless the speaker has been abused, but the level controls are almost invariably corroded and will need to be removed and completely cleaned or replaced. The original controls work best and can usually be refurbished with a Dremel tool, but according to some folks, there are some replacement versions that match the original pretty well (16-ohm, 25-watt).

--Tom Tyson

Attachment: AR-3 in Oiled Teak

[oldguide]

Congratulations--both for your find and for getting such a deal on it--and welcome to the forum.

I was a newbie like you several years ago with a pair of AR3s and had never even been inside a speaker before although I had a lot of wiring, soldering experience. Now I have a great pair of speakers.

As for the rebuild, step one is to download what I call the Bible--the AR3a restoration manual. It is invaluable. There are a few differences between the 3 and 3a, but nothing that you cannot handle. The guide walks you through pretty much everything from cleaning pots to coating the woofers and has some great illustrations, so start with that and use it to plan your moves. When you get stuck, post your question and one of the experts will be there to help.

The aluminum wire can be a PITA. For me what worked was both using crimp connectors and also twisting the wires together such that the solder joint served as a crimp. Tinning the wires first makes it easier.

You did not mention the exterior, which means it must be in good shape--which means you REALLY have a find.

TomT and some of the others might also be able to help you date your speakers if you have the serial numbers.

As for the Fisher, Vacuum Tube Valley sells some nice rebuild kits. If you have not yet turned the Fisher on--don't. Sometimes, although fortunately very rarely--the old caps can blow. You can build yourself a poor man's Variac with a light bulb circuit that will allow you to safely test it. The principle is the wattage of the light bulb controls the current going to the amp so you can slowly step it up using low watt then higher wattage bulbs. Just search for Dim Bulb Tester. Some of those old Fishers used Telefunken and Amperex tubes, which if good can be worth well over $100 for a set of four, so even if the amp is not repairable, you may be able to sell the tubes. The valuable Telefunkens have a diamond on the bottom.

One note of caution which is in the manual, but bears repeating--if the stuffing is original it is nasty stuff, so wear a mask and gloves when working with it. Then toss it.

Also a final note, if you do the repairs recommended in the manual you won't be sorry. They are great sounding speakers.

BTW--may have some tweeters, email me. A member of the forum helped me out and this is a chance to return the favor for someone else.

[GD70]

Congratulations! You got an exceptional deal for those. Amazing condition.

I restored a pair two years ago, found them at my local SA for 19.99! They needed a ton of work, two dead tweeters, early style pots badly corroded and cabs somewhat beat up. Based on the serial numbers, seems they are from 1960. They have the oil caps, which I left in place. I've had two tweeters with slightly popped domes I was able to glue back down with Aileens Tacky glue that were successful.

Roy helped me out with some nice clean pots, a piece of wood from a donor cab for the front trip lip that was damaged online.

Anyway, they are now gorgeous, and sounding superb! 

I have a thread here with links to some of my restorations including the AR3's you may find interesting and helpful.

Cheers, Glenn

[samberger0357]

Glenn you realize that you're responding to a post that's almost 7 years old, right?

However, great info, as always. 

[GD70]

Duh, I do now!

l guess the OP didn't follow up with an outcome.

Thanks!