Resurrecting my AR-2x's

First off, I want to thank ozmoid for his great set of threads on the rebuild of his 2ax's! And redpackman's, Snow's, and Thom's threads, too.

I picked these up for the cabinets. Super-inexpensive, so I took the sellers word that they were horrible/scratchy sounding and presumed they were "dead". Took the grills off yesterday (not easy with 15+ staples and glue and tight fit) and found both woofers were separated from the cast baskets. Pulled the old rheostats and found they were loaded with corrosion. I was out nothing so I cleaned the rheostats to the best of my understanding and tried again. BOOM! Tweeters are both working. I glued the surrounds down and went to bed. (That process, along with getting the laundry through the washer/drier, took 5 or 6 records…written, it sounds like nothing, yet that was a real project for me.)

Fired them up and am listening now and have a pile of question:

1) The woofers have a scratchiness (like a radio station not tuned in well) that for the most part goes away with a little touch on the "rubber" ring on the cone. Any idea on what that is scratchiness is telling me? If this helps, I initially had them tweeters down (see comment e, and I had them on some other speaker cabs so the tweets were at ear level that way). I flipped them over (tweets up), and that seems to have helped get rid of some of the scratchy noise. ???

2) With the little bit of research I have done, I am not convinced there is an absolute way to preserve the surround and/or the "rubber" ring. Is there???

3) The tweeters are working and sound pretty good considering they are as old as I am!!! Is there any reason to pull them out?

4) You can see the cap that is in them (obviously original, correct?). Are they the oil filled ones I have read about that may not require replacing? And how do I test them without taking them out?

5) I am a little embarrassed to ask, but this is how we learn… Was I wrong using Elmer's white glue to put the surround back down?

Comments:

a) I just dropped the needle on the Who's "Who's Next" and man, the "performance" is deep and wide…at times like I could reach up and grab parts of the sound right by my ears!!! I know that sounded weird, yet even as rough as they are, they have a special "life" about them.

b) There was no wire mesh around the woofer's baskets like I've seen in other threads' pictures. What was there was a sheet of thin, felt'ish packing-type stuff tucked all the way around all the chunks of insulation with the wires ran right through the middle of it. Is that weird or help date them in any way?

c) The heads of the philip's recess bolts holding the tweeter in have been peened. Is that to keep me out? Were they expected to last forever? [From other threads and forums I have read, that does NOT appear to be fact. ]

d) One of the jumpers has round, washer-type ends and the other has slot types. Considering the serial numbers are X 04926 & X 04905, I was surprised to see any differences.

e) There are 5 felt pads on the tweeter end of the cabinets. Are those original? In another way, were these designed to be set up with the tweeters by the floor???

I am looking forward to everyone's input. Thanks in advance.

Very brief response here, but I just want to suggest that your problems all sound normal and very fixable for nearly 50 year-old speakers. Those woofers are terrific, but I suspect something is still loose: either the cloth (not rubber) surround is not fully adhered to the masonite ring, or the ring is not fully adhered to the metal basket. It is also possible that this noise could be caused the lower masonite ring (viewed only after woofer is removed) having become detached from the metal basket frame.

Good job cleaning up the rheostats, but those caps, which are original, are not the type which are worth testing and keeping at this point. One good quality simple 6mf poly cap for each would be a prudent investment.

More pics would be helpful. Keep us posted.

Your tweeters seem ok but if you have the phenolic ring tweets, they are available from parts express for 15$ each.

Congrats on the 2a's! They look pretty good. If they sound as good as the 2ax's I rebuilt 6 years ago, you'll be a happy camper. Not sure I will ever let go of mine. They were my first re-foam... the "gateway drug" if you will.

I believe the replacement surround kits come with PVA glue, which is similar to Elmer's Glue-All, however don't quote me on this. You probably could have done worse...

Replace those caps for sure.

Thanks for the input so far!

Ra.ra: "either the cloth (not rubber) surround is not fully adhered to the masonite ring, or the ring is not fully adhered to the metal basket."

Masonit ring???!!! Here is a pic I have on my phone of how both woofers looked having been lifted out of the cabs. I take it I am missing something since there is nothing above or below (only basket and surround)???

What appears to be seperate from the basket must be glued to the basket.
The surrounds can be resealed with the correct sealer ebay seller "vintage-ar" sells.

Is that separation complete or only partial as you pic shows. Alignment of the voice coil is critical when re gluing this to the basket. You may want to carefully cut the dust cover 95% leaving a little still attached and flip it open like a lid. Shim the VC while the glue dries. Then re glue the dust cover back in it's original position and you should be good.

Good luck!

Thanks for that info, GD70.

So the "scratchiness" could be because I glued with the one side attached and now it's not centered?!?

They were about 80% separated. I take it I would want 100% separated, shim, and then glue down, correct?

tt: your pic in post #5 is what I suspected (your finger appears to be resting on the edge of the ring) - - - that old glue has finally given up and the rigid masonite ring has become detached from the metal basket. GD70 makes a great point, though - - you want to be certain that everything is fully centered before re-attaching the surround ring to the basket.

80% separation is pretty substantial, but I suppose it's possible that the VC could remain properly centered. Still, with that much already dislodged, I'd probably be inclined to fully separate the parts, shim and then re-glue the entire perimeter with many small clamps.

or instead of shimming, while the glue is wet, run a 30hz tone at low levels through the woofer, and adjust the surround to remove any scratchiness, and use spring loaded clothespins around the perimeter of the surround to clamp the surround to the basket while it dries

tube tied said:

e) There are 5 felt pads on the tweeter end of the cabinets. Are those original? In another way, were these designed to be set up with the tweeters by the floor???

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I have a set of 2ax's that I got a GW a few weeks back. Mine have the felt pads on the tweeter end of the cabinet as well. Look forward to someone providing some insight to this also!

I'm not aware of any felt pads from the factory. They might have been mounted upside down if they were sitting on a shelf, and the owner wanted the tweeters at ear level.

RxDx said:

I'm not aware of any felt pads from the factory. They might have been mounted upside down if they were sitting on a shelf, and the owner wanted the tweeters at ear level.

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Actually AR did include felt pads, with instructions...see attached photo.

Roy

There were 4 square pads on mine - one on each corner of the top. You could tell by looking at them that they were quite old. I would guess as old as the speaker itself.

Never thought of placement on a shelf and being oriented so the tweet and mid were at ear level. That makes sense.

I second the glue from vintage-ar. I just refoamed my 2ax's with his kit, and the glue tacks up well, but you have a minute or 2 to repositon if needed. I took a chance and used the battery method because I wanted to keep the original dust caps intact. It was only my second foam job and went surprisingly smooth.

ra.ra said:

tt: your pic in post #5 is what I suspected (your finger appears to be resting on the edge of the ring) - - - that old glue has finally given up and the rigid masonite ring has become detached from the metal basket. GD70 makes a great point, though - - you want to be certain that everything is fully centered before re-attaching the surround ring to the basket.

80% separation is pretty substantial, but I suppose it's possible that the VC could remain properly centered. Still, with that much already dislodged, I'd probably be inclined to fully separate the parts, shim and then re-glue the entire perimeter with many small clamps.

Click to expand...

On these woofers, both the surrounds and the spiders are glued to Masonite rings that are glued to the cast baskets. It is very common for both rings to become detached from the baskets. They have a relatively long throw voice coil. When the glue attaching either of the Masonite rings to the baskets begins to fail, as the rings pull away from the baskets, more linear stress is placed on both rings, accelerating the failure of attachment on both surfaces. More often than not, I will lift the entire moving diaphragm from the basket, clean the residue out of the area that is under the spider and in the voice coil gap that is the result of the spider ring detachment, and re-install the entire moving diaphragm. While I can understand a desire to keep the original dust cap intact, you absolutely want that voice coil to be on direct center. All the dust cap does, at least in this case, is keep dust out of the VC gap. You don't necessarily have to destroy the cap to shim the voice coil - it can usually be lifted out after softening the glue with acetone, but doing that can also compromise the integrity of the voice coil and spider glue joints at the cone. Be careful if you take that road!

Good luck with your restoration! :thmbsp:

This has become "fun"!

I now have two more questions.

1) It appears from the research I did last night, that I will have to get a 5.6 uf & a .33 uf to get the 6.0 uf capacitor replaced. Correct? Or will any poly work, because I also saw this: "Wired CBB60 6uF AC450V Polypropylene Film Motor Capacitor" on Amazon.

2) While I am at this, should I wire in some sort of protection circuit? And what would that "look" like?

Putting the 5.6 and the .33 in parallel will get you right where you need to be.

To replace my 6uf, I got a 6.2uf poly from Parts Express. A little on the high side but I think it will be close enough. I'll check it first. If it's much over 6.2, I may go a different route.

Never used caps designed for motors. Don't know enough about the differences between the two to have an informed opinion.

What is the tolerance on the original? 6 to 6.2 is less than 5% difference anyways; the tolerance on the original caps was probably more than that!

MacNoob said:

What is the tolerance on the original? 6 to 6.2 is less than 5% difference anyways; the tolerance on the original caps was probably more than that!

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Exactly. Not sure what the original's tolerance was but I would be surprised if it was less than 10%.

The 6uf I am replacing reads 9.4uf now

Attached are some links to 6mf caps that I like to use in AR speakers.

http://www.erseaudio.com/Products/PulseX250v/MPX25-03-6-00
http://www.erseaudio.com/Products/PEx250v/6uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor
https://www.madisoundspeakerstore.com/carli-capacitors/carli-mylar-6-mfd/