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AR-2ax Silent Tweeters


DesignInc

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AR-2ax Problems

I found my first pair of AR's and have done some testing/cleaning but not sure what testing to do now to get the tweeters going. I am impressed with the build quality of these compared to my Dynaco A-25.

WHAT: AR-2ax - woofer dated March 1972 – foam surrounds, 3.5” mid, .75 tweeter

NEEDS: fix silent tweeters, woofer re-foam re-cap with Sonicaps 6mfd & 4mfd

DONE: cleaned and lubricated pots, replaced small wire that connects post 2 to the “T” post with a piece of solid copper 12 gauge wire.

Before I do the refoam I need to figure out why the tweeters have zero sound (tested with paper tube} I did rotate the pots all around even though they appear fine. Is there a way to test to see if they are getting info or not. Besides de-soldering them and putting in a known good speaker? I do have a multi-meter but not very familiar with its use. I do find it odd that both tweeters have the same problem.

• If no info is getting to the tweeter could it be a bad cap?

• Is there a way to test the two cap lines to check there resistance? How?

• can I jump the pot to eliminate that possibility?

The pots look really good and (I did clean off a little corrosion on one of them) and lubricated them with a silicone spray. I only de-soldered the woofer, popped the retainer on the pots and cleaned/lubricated through the woofer hole.

I want to listen to them the way AR intended them to sound and am NOT interested in replacing pots and speakers unless they are NOS or used originals.

Thanks a lot, David

post-105752-0-81433900-1311201017_thumb.

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AR-2ax Problems

DONE: cleaned and lubricated pots, replaced small wire that connects post 2 to the “T” post with a piece of solid copper 12 gauge wire.

Thanks a lot, David

Hi David

I do believe you removed a chrome wire, actually it may be Nichrome resister wire.

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Hi David

I do believe you removed a chrome wire, actually it may be Nichrome resister wire.

uh oh ... that wire was broken or I broke it taking the post off ... see attached

Is that what you are talking about?

post-105752-0-11648800-1311217169_thumb.

post-105752-0-13947200-1311217190_thumb.

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I cleaned both pots on one speaker, but the other speaker has the same problem with the tweeter "zero sound" any ideas?

measure across the tweeter posts for continuity....of it's open, tweeter are probably toast. if you get something in the 4-6ohm range, you're probably OK with the tweets...

next up, I'd attempt to jump across the pot to see if you get sound....otherwise it could be that the cap is open...

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measure across the tweeter posts for continuity....of it's open, tweeter are probably toast. if you get something in the 4-6ohm range, you're probably OK with the tweets...

next up, I'd attempt to jump across the pot to see if you get sound....otherwise it could be that the cap is open...

Well even though the tweeter has continuity and resistance similar to some of my other speakers 10 - 13 ohm I decided to take a feed of the pot with alligator clips and when I fed it to a known good speaker (the woofer) it did get sound. Then I tried connecting the clips to the back of the tweeter ... no sound, then tried the clips on the front posts ... no sound. I'm afraid the tweeter is not working.

Anyone have working tweeters? They were also used in the AR-3a, AR-5

I guess if it was easy people would never get rid of these vintage speakers. but I am kind of bummed.

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If the original dual section square capacitor is still in the circuit it is undoubtedly bad and the tweeter will not work.

The best way to test the tweeter is to connect a replacement 4mfd cap in series with it and directly to the amplifier output. If it is going to work, that should prove it. If it works that way but doesn't work connected to the pot, it's possible the pot was reassembled incorrectly or was not rewired correctly after it was cleaned. If you did not or do not put the cap in series with the tweeter, between the tweeter and the amplifier, it will probably be badly damaged. Also the wires to these tweeters are very fragile and easily damaged both physically and with too much heat from a soldering iron. Once damaged they are next to impossible to repair. There have been no comparable replacement tweeters manufactured in recent decades. The philosophy of wide dispersion these tweeters embodied in not the fad du jour. Today's tweeters are almost all deliberately manufactured to focus their high frequency energy over a relatively narrow solid angle like a beam compared to these classic model AR dome tweeters.

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If the original dual section square capacitor is still in the circuit it is undoubtedly bad and the tweeter will not work.

The best way to test the tweeter is to connect a replacement 4mfd cap in series with it and directly to the amplifier output. If it is going to work, that should prove it. If it works that way but doesn't work connected to the pot, it's possible the pot was reassembled incorrectly or was not rewired correctly after it was cleaned. If you did not or do not put the cap in series with the tweeter, between the tweeter and the amplifier, it will probably be badly damaged. Also the wires to these tweeters are very fragile and easily damaged both physically and with too much heat from a soldering iron. Once damaged they are next to impossible to repair. There have been no comparable replacement tweeters manufactured in recent decades. The philosophy of wide dispersion these tweeters embodied in not the fad du jour. Today's tweeters are almost all deliberately manufactured to focus their high frequency energy over a relatively narrow solid angle like a beam compared to these classic model AR dome tweeters.

thanks, soundminded

I will give that a try with the 4mfd cap, I assume I can do that without desoldering the lead wires. ... David

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thanks, soundminded

I will give that a try with the 4mfd cap, I assume I can do that without desoldering the lead wires. ... David

YEAAAAAAAAAAA! I have tweeter sound! FYI: I got a cheapo 4.7mfd at Radio Shack for $2 (albiet electrolytic) just to test this out. Now I plan to order Sonicaps because of great reviews and they make exact 6mfd and 4mfd caps. Thanks again to all.

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