AR-2Ax Version? & Rebuild Results

[2s56p94imp]

I am trying to determine where my AR-2Ax speakers fit in the chronological order of this model series. The units I have were purchased as part of a speical offer to service technicians while I was working for a Hi-Fi dealer in Austin, TX in the 1964-1966 time period. The serial number sequences are 36974 and 36981. These were the typical oiled walnut finish with name plates saying just "AR Inc." and a separate brass "a" script plate that was pinned to the grill cloth on an opposite corner. These units still used the 10" woofers with the cloth surround, but had the 1 3/8" red-brown dome tweeters with the aluminum voice coil leads, and the phenolic ring type mid-range driver behind an expanded metal cover.

I see pictures of AR-2Ax speakers that had two angled mid-range drivers plus a smaller dome tweeter. The tweeters on my units had 4 foam dots around the periphery not three like I see in pictures of some similar AR-2 series speakers.

Unfortunately, the tweeters on my speakers were popped loose from their thin clear rubber surrounds. One was far enough out that the voice coil could clearly be seen. I managed to get them back into relatively correct position and used a thin layer of clear silicon caulk to reseal the edges of the domes. The speakers were lying on their backs with a suitable weight to keep the domes in correct position over-night while the caulk I used cured. However, the tweeter output level did not seem right - too low. I concluded that the combination of my repair attempt and the deterioration of the foam rods that seem to center the voice coils of the tweeters had reduced the ability of the voice coils to move the assembly through a normal range of motion. Accordingly, I decided to replace the tweeters with the HiVi Q1R tweeters following instructions found on this web site.

I also replaced the original level controls with 8-ohm L-Pads and used the 0.05mH coils added to the tweeters. The original level controls were too far gone with corrosion and the moving element of one was corroded completely through. The mid-range drivers were in good shape and the only change there was to add the 25-ohm 10 watt wire wound resistor across the L-Pad to keep the cross-over frequency knee at the same point as the original design. The cross-over circuit was modified to 3mFd polypropylene capacitors for the tweeter circuit and the 6mFd polypropylene capacitors for the mid-range drivers. The tweeters were installed with the leads connected with reverse polarity following the instructions on this web site.

I did away with the separate "T" tweeter connection and elected to just use the "1" and "2" connections. I used new gold plated binding posts which will accept bananna plugs or stripped wire ends. The parts all came from Parts Express. The holes left from removing the "T" connection point were filled with the original screw and nut from the OEM binding post. The old binding hardware was corroded almost as bad as the original level controls.

The woofers had to have their masonite rings re-glued to the speaker basket or frame. The old glue had separated from the basket in both speakers. I used the Aleene's Tacky Glue recommended.

The result has restored proper operation and they are again outstanding speakers! I have enjoyed them now for several days and still am amazed how good they sound.

[2s56p94imp]

I thought I would add some illustrations of the re-wiring inside the cabinets of my AR-2A^x speakers. These were originally done in AutoCAD and exported as image files which were converted to *.pdf format. I forgot to add these with my first post.

Joe

AR_2AX_Crossover01.pdf

AR_2AX_Crossover02.pdf

AR_2AX_Crossover03.pdf

AR_2AX_Crossover04.pdf

[Steve F]

I have written many times on the succession of the AR-2 family. Long-time readers will no doubt be bored by this, so I apologize in advance:

The AR-2 series was indeed a complicated, drawn-out affair.

This is a reasonably accurate chronology of events. The order of model introduction shown below is pretty accurate; the actual dates may be off a little here and there.

1957—AR-2 intro’d as follow-up to 1954’s AR-1.

AR-2 has 10” w, (2) 5” tweeters, x-o 2000Hz.

1959-60 AR-2a added, includes 1 3/8” brown-colored dome tweeter of AR-3. x-o is 2000, 7500 Hz.

1964—First-generation AR-2ax replaces 2a. Dual 5” drivers replaced by single 3 ½” midrange (not a "phenolic ring," BTW. Just a regular 3 1/2" cone.). Retains 1 3/8” tweeter.

AR-2 replaced by AR-2x. Again dual 5” drivers replaced by single 3 ½” driver.

AR offers factory upgrade kit to customers who wish to upgrade their older 2 to 2x or 2a to 2ax status.

2x and 2ax live side by side until 1970.

1970—“New” 2ax and 2x replace the first-generation 2ax and 2x.

2ax uses 5’s 10” woofer with foam surround, retains 3 ½” mid, uses new ¾” dome tweeter (black in color), also from the 5. x-o is now 1400, 5000 Hz. Logo badge is changed from “AR” square and brass “a” to 3a-styled logo with red de-bossed “AR-2ax” on a rectangular brass field.

2x changes to 5’s woofer and 4x’s 2 ½” tweeter. X-o changes from 2000 Hz to 1200 Hz.

New 2ax and 2x live side by side.

2x quickly fades away, but 2ax lives on until 1975 or 76 when ADD series is intro’d.

Steve F.

[2s56p94imp]

Steve;

Thanks for your response. Then my speakers were the first generation AR-2A^x series. I saw a comment elsewhere that made me think the mid-range driver was a phenolic ring type - sorry for the misunderstanding. I just finished replacing the grill cloth with a medium gray color using a synthetic material that should resist stains better than the original linen type material. The glue is still drying. I plan to put velcro tabs on the grills to permit removal if service or changes are desired in the future.

It appears from looking at other member's posts showing pictures of their AR-2A^x speakers that the badges varied considerably over time as well.

There are two printed lables on the back of the cabinets. One is printed on card stock and is quite yellow with age. The other was printed on a thinner paper that is still quite white in appearance after 40+ years.

Thanks to everyone on this site for all the detailed work in evaluating various drivers for these speakers. The response curves of before/after tests are quite helpful.

Joe

[Steve F]

Hi Joe,

Yes, you have first-generation 2ax's. Both gens were great speakers, and in my estimation represented the best performance-per-dollar ratio of the entire Classic series (we refer to the original 1954-1974 speakers as the 'Classic' ARs).

The logos changed once, from first-gen to second-gen:

"1970—“New” 2ax and 2x replace the first-generation 2ax and 2x.

2ax uses 5’s 10” woofer with foam surround, retains 3 ½” mid, uses new ¾” dome tweeter (black in color), also from the 5. x-o is now 1400, 5000 Hz. Logo badge is changed from “AR” square and brass “a” to 3a-styled logo with red de-bossed “AR-2ax” on a rectangular brass field."

Enjoy them.

Steve F.