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Ibis

AR 2ax serial numbers

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Hi

Ive just picked up a pair of 2ax speakers for a pittance and with a few turns of the pots all the units seem to work fine.

I was going to use the tweeters for restoring a pair of 5s but they seem to good to break up.

I think they are quite old as they have an 11 in woofer with a cloth surround

The serial numbers are 99662 and 99965 and I was wondering if the big gap between the numbers meant they weren't an original pair ?

Also the veneer on the top is quite a few shade lighter on one than the other yet at the side its the same darker colour, I guess this could be just bleaching by the sun or someone trying to remove a red wine stain or similar. I think they are genuinely darker than the teak AR 7s I had.

The cabinets seem very good and air tight in so much the woofer seems damped, I really like the sound, nice mid and bass with a very natural sound stage.

Is there any other basic things I can do apart from removing the woofers to get in and clean the pots?

I apologise if this may have been covered in other threads but I am a bit new to navigating round here.

Any help would be much appreciated

Thanks

Ibis

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Beautiful! These projects "can" get away from us. So now you're still stuck with the problem of finding a tweet for your AR-5. ;)

Regarding the SNs, yours are very close. No problem. These were not sold as pairs since stereo was relatively new at the time. I have a pair of 2ax's very similar to yours and they are SN 41070 and 40214. No problem. As far as the difference in color, as my friend the woodturner says; "if you want uniformity buy Formica." :lol:

That stain is unfortunate but maybe with some bleach and stain you can hide it.

Inside the box: Be careful removing the delicate, crumbly Kempac (sp?) that keeps fiberglass dust out of the woofer. If it is beyond salvage you can replace it with fine fiberglass window screen or crinoline cloth.

I recommend replacing the caps. The original cap is a dual-value wax block. You can leave it in place but cut the leads and install a 4uF cap and a 6uF cap. Film caps are best and those values are cheap. If your pots don't clean up you can use L-pads. The thread (below) has a photo of the xo from my 2ax. I used two 3uF caps for the 6uF only because that's what I had on hand.

Here's the full story on that restoration:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=4466&st=0&p=73966entry73966

Good luck

Kent

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Beautiful! These projects "can" get away from us. So now you're still stuck with the problem of finding a tweet for your AR-5. ;)

Regarding the SNs, yours are very close. No problem. These were not sold as pairs since stereo was relatively new at the time. I have a pair of 2ax's very similar to yours and they are SN 41070 and 40214. No problem. As far as the difference in color, as my friend the woodturner says; "if you want uniformity buy Formica." :lol:

That stain is unfortunate but maybe with some bleach and stain you can hide it.

Inside the box: Be careful removing the delicate, crumbly Kempac (sp?) that keeps fiberglass dust out of the woofer. If it is beyond salvage you can replace it with fine fiberglass window screen or crinoline cloth.

I recommend replacing the caps. The original cap is a dual-value wax block. You can leave it in place but cut the leads and install a 4uF cap and a 6uF cap. Film caps are best and those values are cheap. If your pots don't clean up you can use L-pads. The thread (below) has a photo of the xo from my 2ax. I used two 3uF caps for the 6uF only because that's what I had on hand.

Here's the full story on that restoration:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=4466&st=0&p=73966entry73966

Good luck

Kent

Thanks Kent for your excellent advice,

It didnt occur to me that we were going back to pre stereo; because the mid and tweet apertures were not bookmatched ( mirrored) I thought I may have a couple of lefts or rights...We live and learn!

That in my mind makes their sound all the more remarkable as they integrate so well together with out the feeling that the sound is coming out of two boxes, something that I liked very much with some old Snells.

Is replacing the caps easy? I know nothing about electronics but I can solder OK, Are there significant improvements in the sound or is it a case of " if your in there its a good job to do incase they fail" ?

I checked out the link to yours and I must say youve made a beautiful job,

I will post a few pics when I " go in" as I may seek your advice re the caps. In the mean time the hunt is on for some tweets for the 5s or I bite the bullet and get the HiVis and offset the shipping and import tax against my bargain 2ax

Thanks again

All the best

Ibis

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As far as I know, no 3-way/3-driver AR speakers of the classic era (up to/including the LST) were book-matched. The LST was the first 3-way AR speaker that might be said to be bookmatched though there was never a performance or benefit claim re that for the speaker. I think it is "bookmatched" just because it was logical to build it that way, not because there is any real sonic advantage to it.

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Hi

Ive just picked up a pair of 2ax speakers for a pittance and with a few turns of the pots all the units seem to work fine.

I was going to use the tweeters for restoring a pair of 5s but they seem to good to break up.

I think they are quite old as they have an 11 in woofer with a cloth surround

The serial numbers are 99662 and 99965 and I was wondering if the big gap between the numbers meant they weren't an original pair ?

Also the veneer on the top is quite a few shade lighter on one than the other yet at the side its the same darker colour, I guess this could be just bleaching by the sun or someone trying to remove a red wine stain or similar. I think they are genuinely darker than the teak AR 7s I had.

The cabinets seem very good and air tight in so much the woofer seems damped, I really like the sound, nice mid and bass with a very natural sound stage.

Is there any other basic things I can do apart from removing the woofers to get in and clean the pots?

I apologise if this may have been covered in other threads but I am a bit new to navigating round here.

Any help would be much appreciated

Thanks

Ibis

Ibis,

Just a few observations here: the tweeters in your AR-2axs are the 1⅜-inch AR-3 version -- used from 1959 until early 1970 -- until the addition of the newer ¾-inch tweeter, along with a change in the woofer. Therefore, the AR-3 tweeters cannot be used in the AR-5, which used an 8-ohm version of the ¾-inch tweeter and a new woofer. Since your AR-2ax versions have the 3½-inch midrange driver, they would have been built between 1965 and late 1969 or so. The woofers in your units are the original-style AR-2 Alnico-magnet version, and this woofer usually works fine as long as the original owners didn’t try to over-power the speakers. If your woofer cones return slowly after carefully being pushed inward around ½ inch or so, then the acoustic seal is fine. If the cone returns quickly after being pushed in (push around the inner edge of the cone with fingers around the dust cover), then the acoustic seal is not intact and will have to be dealt with accordingly.

There were tens of thousands of AR-2axs built during this period, and this speaker system received wide critical acclaim, check-ratings and excellent reviews, and was one of the most popular loudspeakers sold during those years. By the way, AR never made “sequential-pair” serial numbers for the original speakers built up until the 1990s. It is therefore coincidental that you would find any two speakers with sequential or even closely matched numbers.

As for the finish differences, this isn’t unusual. You can go through and refinish the cabinets by sanding and then you can use Watco or similar oil with Walnut stain, and at the time you can bring both speakers closer in tint. The original AR-7, however, was only available in a “Walnut Finish” Birch veneer, and then later only in a vinyl Walnut finish. It was never available in Teak.

As for the capacitors. These are the Chicago Industrial plastic-encapsulated units (they are not wax units although they are covered with some paraffin to help seal them against moisture), and although they will often drift in value somewhat over time, first fix the level controls and check to see how the speakers work. If you detect distortion or problems with the drivers, you may need to replace the capacitors. It is not mandatory that you always do this, however, and you should check the sound and operation after refurbishing the level controls. Of course, if in doubt, change out the capacitors.

--Tom Tyson

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Hi Tom

Thanks for your time making such a comprehensive reply, I really appreciate your help.

Just to confirm that you are spot on with the dates I cleaned the pots today and on the inside of the cabinet was written the date 16th Nov 1968 !

They are all back together, the wine stain almost gone with a combination of bleach, burnishing cream and wood reviver .... quite a smelly day.... the linen fronts are in the washing machine ( just an experiment as one is ripped and Ive ordered some more fabric)

Will post some pics soon

Thanks guys for your invaluable help

Ibis

Ibis,

Just a few observations here: the tweeters in your AR-2axs are the 1⅜-inch AR-3 version -- used from 1959 until early 1970 -- until the addition of the newer ¾-inch tweeter, along with a change in the woofer. Therefore, the AR-3 tweeters cannot be used in the AR-5, which used an 8-ohm version of the ¾-inch tweeter and a new woofer. Since your AR-2ax versions have the 3½-inch midrange driver, they would have been built between 1965 and late 1969 or so. The woofers in your units are the original-style AR-2 Alnico-magnet version, and this woofer usually works fine as long as the original owners didn’t try to over-power the speakers. If your woofer cones return slowly after carefully being pushed inward around ½ inch or so, then the acoustic seal is fine. If the cone returns quickly after being pushed in (push around the inner edge of the cone with fingers around the dust cover), then the acoustic seal is not intact and will have to be dealt with accordingly.

There were tens of thousands of AR-2axs built during this period, and this speaker system received wide critical acclaim, check-ratings and excellent reviews, and was one of the most popular loudspeakers sold during those years. By the way, AR never made “sequential-pair” serial numbers for the original speakers built up until the 1990s. It is therefore coincidental that you would find any two speakers with sequential or even closely matched numbers.

As for the finish differences, this isn’t unusual. You can go through and refinish the cabinets by sanding and then you can use Watco or similar oil with Walnut stain, and at the time you can bring both speakers closer in tint. The original AR-7, however, was only available in a “Walnut Finish” Birch veneer, and then later only in a vinyl Walnut finish. It was never available in Teak.

As for the capacitors. These are the Chicago Industrial plastic-encapsulated units (they are not wax units although they are covered with some paraffin to help seal them against moisture), and although they will often drift in value somewhat over time, first fix the level controls and check to see how the speakers work. If you detect distortion or problems with the drivers, you may need to replace the capacitors. It is not mandatory that you always do this, however, and you should check the sound and operation after refurbishing the level controls. Of course, if in doubt, change out the capacitors.

--Tom Tyson

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Just a few observations here: the tweeters in your AR-2axs are the 1⅜-inch AR-3 version -- used from 1959 until early 1970 -- until the addition of the newer ¾-inch tweeter, along with a change in the woofer. Therefore, the AR-3 tweeters cannot be used in the AR-5, which used an 8-ohm version of the ¾-inch tweeter and a new woofer. Since your AR-2ax versions have the 3½-inch midrange driver, they would have been built between 1965 and late 1969 or so.

--Tom Tyson

Hi Tom,

While I don't advocate tearing apart a pair of AR-2ax's or 3's to transplant the earlier orange dome tweeter into a pair of AR-5's, it would be interesting to see how those tweeters would fare in the 5's. The early AR-2ax used virtually the same crossover as the later, and both versions of the 2ax were considered to be 8 ohm speakers. Further, the simple 4uf capacitor tweeter crossover was the same for all iterations of the 2ax as well as the 5. The only variable would be how the early 2ax tweeter interacts with the later woofer, the crossover circuit of which (in the 2ax) was very nearly the same (#5 coil vs #7 coil).

Roy

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Hi Tom,

While I don't advocate tearing apart a pair of AR-2ax's or 3's to transplant the earlier orange dome tweeter into a pair of AR-5's, it would be interesting to see how those tweeters would fare in the 5's. The early AR-2ax used virtually the same crossover as the later, and both versions of the 2ax were considered to be 8 ohm speakers. Further, the simple 4uf capacitor tweeter crossover was the same for all iterations of the 2ax as well as the 5. The only variable would be how the early 2ax tweeter interacts with the later woofer, the crossover circuit of which (in the 2ax) was very nearly the same (#5 coil vs #7 coil).

Roy

To my way of thinking, the newer 3/4" tweeter might be more usable in the older 2ax than the other way around. The new tweeter crossed over at 5000 Hz, so it would be relatively "safe" crossing over at the higher (7500 Hz, right?) crossover point of the earlier speaker.

The reverse may not be true: Would the 1 3/8" orange dome from the 'old' 2ax be happy crossing over at the 5000 Hz x-o point of the new 2ax? Maybe not--depends on the two drivers' parameters, and I don't have those in front of me.

This is quite apart from any system tonal or driver blending considerations, which could be another matter altogether.

Steve F.

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To my way of thinking, the newer 3/4" tweeter might be more usable in the older 2ax than the other way around. The new tweeter crossed over at 5000 Hz, so it would be relatively "safe" crossing over at the higher (7500 Hz, right?) crossover point of the earlier speaker.

The reverse may not be true: Would the 1 3/8" orange dome from the 'old' 2ax be happy crossing over at the 5000 Hz x-o point of the new 2ax? Maybe not--depends on the two drivers' parameters, and I don't have those in front of me.

This is quite apart from any system tonal or driver blending considerations, which could be another matter altogether.

Steve F.

Regardless of the published/stated crossover point, both tweeters were used in 2ax cabinets with exactly the same system crossover components and midrange! In other words, AR removed the orange dome tweeter and dropped in the 3/4" tweeter, and swapped in a foam surround woofer, changing nothing else. This somehow resulted in a new tweeter crossover point spec. I don't see either tweeter being more or less at risk. If that were the case the orange dome tweeter would have been "at risk" in the earlier 2ax. A 4uf filter is a 4uf filter. I agree, the sound differences are another matter.

I suspect the resistance presented by the level controls have something to do with the determination of the published tweeter crossover points. The midrange and its associated crossover component (6uf cap) were also the same for both versions. The woofers differed (cloth vs foam), but the original woofer crossover coil (#5) did not change when the 3/4" tweeter was introduced. That was changed to the larger #7 coil after the smaller, standard flange foam surround woofer was introduced.

Roy

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Regardless of the published/stated crossover point, both tweeters were used in 2ax cabinets with exactly the same system crossover components and midrange! In other words, AR removed the orange dome tweeter and dropped in the 3/4" tweeter, and swapped in a foam surround woofer, changing nothing else. This somehow resulted in a new tweeter crossover point spec. I don't see either tweeter being more or less at risk. If that were the case the orange dome tweeter would have been "at risk" in the earlier 2ax. A 4uf filter is a 4uf filter. I agree, the sound differences are another matter.

I suspect the resistance presented by the level controls have something to do with the determination of the published tweeter crossover points. The midrange and its associated crossover component (6uf cap) were also the same for both versions. The woofers differed (cloth vs foam), but the original woofer crossover coil (#5) did not change when the 3/4" tweeter was introduced. That was changed to the larger #7 coil after the smaller, standard flange foam surround woofer was introduced.

Roy

what's the nominal impedance of the 1 3/8" orange tweet vs. the newer 3/4" dome? a 4uf filter is a 4uf filter, but for an 8ohm impedance it's a 4970hz crossover point, for a 4ohm impedance, it's a 9940hz crossover point....

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what's the nominal impedance of the 1 3/8" orange tweet vs. the newer 3/4" dome? a 4uf filter is a 4uf filter, but for an 8ohm impedance it's a 4970hz crossover point, for a 4ohm impedance, it's a 9940hz crossover point....

DCR is a bit less than 2 ohms. Between that and level control settings, crossover points differ from that of the later 6 ohm (dcr) 3/4" tweeter. My point regarding the 4uf cap is it will have the same effect on the orange tweeter regardless of the speaker (early 2ax, later 2ax, or 5) the tweeter is installed in. Risk to the driver is the same.

Roy

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My AR2ax after a bit of a tidy up, the pots now work fine and the bad stain on the top is almost gone, just waiting for the grill cloth.

I am really enjoying the sound. A £10 bargain if ever there was one !

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