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New member needs infos on AR-2ax


quebecois59

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Here is a picture of my boxes, before and after. I wet sanded by hand with 1000-grit and tung oil, wiped the fine dust with an oiled cloth, then hand buffed wiith superfine (000) steelwool with tung oil again, then wiped and buffed the surface again with and oiled cloth first and then a dry cloth.

I'm satisfied with the result, I hope for the same with the other box.

http://tinyurl.com/869gfbw

Beautiful! Looking forward to your finished product!

Kent

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Just wanted to say that you are doing a fine job with your restoration - - - asking all the right questions and then proceeding with the most comfortable and practical solution at hand. The refinishing on the walnut cabinets looks really terrific - please do include another update when the project is nearer to completion.

I fully understand those who prefer to replace the control pots with L-pads, but in my own AR speaker restorations, I have preferred to repair and replace the original pots, fussy and persnickety as they may be. While the re-wiring inside these cabinets can be a bit difficult (for me) at times, it has always been better for me to completely remove the pots. This not only allows for improved access for all of the mechanical processes, but more importantly, it makes the pots available for a full immersion in a salt-vinegar liquid bath which creates chemical action on all of the corroded surfaces. Even when there is pitted metal on the pot or the sweep, the subsequent abrasion required feels like a gentler approach after this dunk and soak. Most often, a wire bush or steel (or bronze) wool or emery cloth is required for corrosion removal, but I also like to finish scrubbing these surfaces with an old nylon toothbrush and a fine slurry of baking soda or Bon Ami (see, I speak French!) cleanser. Before final reassembly, be sure to test the results with an ohmmeter, and I also like to spray them with a silicone coating and maybe coat lightly with dielectric grease (both available from auto parts stores).

Last comment: I really liked your excellent pics showing the backside of tweet and mid viewed from inside the cabinet. I assume was done with a mirror placed inside the cabinet, and it showed me that more than one type of T-nut was used in the original manufacturing. Keep up the good work.

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Just wanted to say that you are doing a fine job with your restoration - - - asking all the right questions and then proceeding with the most comfortable and practical solution at hand. The refinishing on the walnut cabinets looks really terrific - please do include another update when the project is nearer to completion.

I fully understand those who prefer to replace the control pots with L-pads, but in my own AR speaker restorations, I have preferred to repair and replace the original pots, fussy and persnickety as they may be. While the re-wiring inside these cabinets can be a bit difficult (for me) at times, it has always been better for me to completely remove the pots. This not only allows for improved access for all of the mechanical processes, but more importantly, it makes the pots available for a full immersion in a salt-vinegar liquid bath which creates chemical action on all of the corroded surfaces. Even when there is pitted metal on the pot or the sweep, the subsequent abrasion required feels like a gentler approach after this dunk and soak. Most often, a wire bush or steel (or bronze) wool or emery cloth is required for corrosion removal, but I also like to finish scrubbing these surfaces with an old nylon toothbrush and a fine slurry of baking soda or Bon Ami (see, I speak French!) cleanser. Before final reassembly, be sure to test the results with an ohmmeter, and I also like to spray them with a silicone coating and maybe coat lightly with dielectric grease (both available from auto parts stores).

Last comment: I really liked your excellent pics showing the backside of tweet and mid viewed from inside the cabinet. I assume was done with a mirror placed inside the cabinet, and it showed me that more than one type of T-nut was used in the original manufacturing. Keep up the good work.

Thanks for your comments.

As for the pictures of from the inside, I simply held my digital camera with one hand and snap the shots hoping the camera was pointing at the right place. I had to take a few pictures before I got it right. I'd be glad if it is useful for someone else eventually. I will post other pictures of the process as it goes on.

What is the recipe for that salt-vinegar solution? I'd like to give it a try. I own a small Dremell-like tool, maybe I could use it for the final polishing of the pots...

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Beautiful! Looking forward to your finished product!

Kent

THanks Kent!

I did some work yesterday evening of the woofer, cutting and scrubbing the old glue off of the metal ring. Before I started that, I read MrSound's manual (online) to make sure I did it right. At some place in the text, it is said to save the gasket for further use. THere isn't any gasket on both of my woofers!

My understanding is that there should be gaskets there to hold the surrounds properly. I'd like to fabricate my own but I wonder what is the best material I could use. But if they are available somewhere at a low cost, I'd consider buying two of them.

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Just MSound or M_Sound. Not Mr or Monsieur ;)

The AR speakers do not have the gaskets mentioned in the instructions. You don't really need them for the refoam job as long as you use enough clamps. If you think a gasket would help, just make one from heavy cardboard.

Below is a photo of my 1st re-foam job: 2ax woofer with a cardboard temporary gasket. You could even use more clamps--the 2nd photo shows re-foaming an Ohm L woofer, which does happen to have an external gasket. That gasket really serves no purpose.

Kent

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Just MSound or M_Sound. Not Mr or Monsieur ;)

The AR speakers do not have the gaskets mentioned in the instructions. You don't really need them for the refoam job as long as you use enough clamps. If you think a gasket would help, just make one from heavy cardboard.

Below is a photo of my 1st re-foam job: 2ax woofer with a cardboard temporary gasket. You could even use more clamps--the 2nd photo shows re-foaming an Ohm L woofer, which does happen to have an external gasket. That gasket really serves no purpose.

Kent

Looking at your second picture made me wonder if lots of cloth pins all around would apply enough pressure to glue the surrounds properly?

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Looking at your second picture made me wonder if lots of cloth pins all around would apply enough pressure to glue the surrounds properly?

Yes--I believe that will work.
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Looking at your second picture made me wonder if lots of cloth pins all around would apply enough pressure to glue the surrounds properly?

Clothes pins and clamps are not necessary at all, and can actually pull the foam out of alignment. Once the cone glue edge is secure, the outer edge is very easy to glue when using shims to adjust the height of the cone..

Roy

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Good tip from Roy. I was following MSound's instructions but I would absolutely defer to Roy's experience here. As a matter of fact, some woofers (the Original Large Advents spring to mind) have the surrounds glued to the back of the frame, making clamps difficult to impossible. In that case, I just pushed the cone into place (this is where shims are really useful) and then pinched the surround to the frame with my fingers, working around the perimeter in a star pattern, the way you would tighten lug nuts on a car.

Kent

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Attach one test lead to the wiper (center terminal) and the other to either of the other terminals, then rotate the wiper and look for dropouts (you don't want any).. It really shouldn't matter which other terminal you test through, and the DCR should vary from around 1 Ohm to around 15 ohm.

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B & 2 (I think)

Thanks Ken and Genek. Now that I know that I have good speakers in hand, I feel a bit too cautious with every step, I guess!

I put the Ohm-meter on the good looking pot and I got a very gradual response between 0 and 15 ohms all over the band. With the pitted pot, I got 0 to 20 ohms with a few blind spots here in there, but not too bad. I'm not sure if I'll put the L-Pads right now, maybe I'll test the performance of the pots before. I guess I could wire all three speakers and listen to them without putting all the insulating wool back to have a rough idea?

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With what I learned working on the box #1, I was quite efficient with box #2 this evening. I removed the woofer and cleaned half of it, unpack the insulating wool and restored both pots. They weren't as bad as pot #1 in box#1, but both of them needed some attention (sanding and polishing).

I realized that a side benefit of the dielectric grease is how smooth the pots operate once greased! Both of them now show very gradual readings on the Ohm-meter without any deadspot.

I hope i'll get my foams soon!

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Can any of you guys tell me if the voice coils on those AR-2ax are that fragile? In the instructions on MSound's web site, there are several warnings as not to tilt the woofer, not to turn them face down, and this and that. Does any of you have a very sad story about these voice coils that could enlight what I should exactly avoid?

Thanks in advance

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The guide that convinced me of the value of the soak solution is here:

http://www.audiokarma.org/forums/sho...28#post3798228

This was written by a young guy in Michigan who caught the audio bug from his father, and it is a terrific and funny (and long) piece of writing with many great pics. It is directed toward the 4x speaker, but applies to all of the classic AR's with the Aetna-Pollak pot controls. The guide is excellent and rather thorough, but I would urge you not to follow Step 14, where the surround goop is applied much too heavily.

And yes, very good point about the dielectric grease - - - it does remove so much of the sweeping contact friction and helps to create a smoother gliding action.

Sounds too late for this pair of speakers perhaps, but maybe try the soak as part of the cleaning of your next pair of classic AR's, which I know you'll be looking for soon.

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The guide that convinced me of the value of the soak solution is here:

http://www.audiokarma.org/forums/sho...28#post3798228

This was written by a young guy in Michigan who caught the audio bug from his father, and it is a terrific and funny (and long) piece of writing with many great pics. It is directed toward the 4x speaker, but applies to all of the classic AR's with the Aetna-Pollak pot controls. The guide is excellent and rather thorough, but I would urge you not to follow Step 14, where the surround goop is applied much too heavily.

And yes, very good point about the dielectric grease - - - it does remove so much of the sweeping contact friction and helps to create a smoother gliding action.

Sounds too late for this pair of speakers perhaps, but maybe try the soak as part of the cleaning of your next pair of classic AR's, which I know you'll be looking for soon.

Well, thanks a lot for that great link! I really don't know if I'll restore another pair of AR speakers one day, but if it ever happens, I will have all the info needed to do it right!

I worked of tops of both boxes this evening...man, what a job! Thanks God the veneer was pretty flat, but it was almost grey and quite rough. Lots of wet sandings in circles first, then with the grain, then superfine steel wool with oil again. I spent almost one hour for these small surfaces but I'm satisfied with the result. I'll send pictures tomorrow.

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That is an excellent how-to, but as ra.ra pointed out he used WAY too much Permatex. According to Roy, the Permatex can be thinned 50% with lacquer thinner, but a MUCH BETTER solution is to buy some of Roy's formula directly from him. It is virtually identical to the original, very thin and remains pliable. It made a night and day difference in my KLH Fives and I've subsequently used it on all my old cloth surrounds.

The other curious thing--the writer spent a LOT of time and effort on those pots (which could have easily been replaced with L-pads) but left the old wax block capacitor (or did I miss something?) Replacing the old cap with a new film cap would have been cheap and easy. If I were doing it today, I'd buy four 10uF surplus caps from Madisound for $0.60 each and put 2 in parallel in each box.

Kent

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That is an excellent how-to, but as ra.ra pointed out he used WAY too much Permatex. According to Roy, the Permatex can be thinned 50% with lacquer thinner, but a MUCH BETTER solution is to buy some of Roy's formula directly from him. It is virtually identical to the original, very thin and remains pliable. It made a night and day difference in my KLH Fives and I've subsequently used it on all my old cloth surrounds.

The other curious thing--the writer spent a LOT of time and effort on those pots (which could have easily been replaced with L-pads) but left the old wax block capacitor (or did I miss something?) Replacing the old cap with a new film cap would have been cheap and easy. If I were doing it today, I'd buy four 10uF surplus caps from Madisound for $0.60 each and put 2 in parallel in each box.

Kent

Hey KEnt

Is this capacitor change you recommend really a must? Is that because the old caps would fail soon or because the new caps make a huge difference with the sound?

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If the old cap has drifted in value, the new caps will make an audible difference. And half-century-old electrolytics probably have drifted. I don't know if the wax ones fail but they do go out of spec.

The L-pads should have toothed lock washers and as long as the nut is tightened they should not budge.

Kent

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I don't know how I could tell if the caps

If the old cap has drifted in value, the new caps will make an audible difference. And half-century-old electrolytics probably have drifted. I don't know if the wax ones fail but they do go out of spec.

The L-pads should have toothed lock washers and as long as the nut is tightened they should not budge.

Kent

I don't know how I could measure if the caps have drifted in value or not (is a Ohm-meter useful for this and how?). Actually I don't mind changing the caps if I can source the right new ones around here because I don't want to pay 30$ shipping and broker fees to buy some in USA, and I certainly don't want to buy something here that will be worse than the old ones.

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