Jump to content

Powerglide

Acoustic Research AR-2ax referb

Recommended Posts

I've been looking out for a set of tired vintage speakers to have a crack at refurbishing. I didn't want anything too flash but on the other hand pointless bringing something back that was never any good in the first place. Came close a couple of times with some British contenders but then a month ago these AR's were posted in need of attention. Knowing nothing about them, a quick google search revealed a somewhat cult following on the East Coast of the States and hard to find a bad review, so I forked over my $95 

 

IMG_0527.thumb.PNG.5ae20732888d235ac13c918086d23ec3.PNG

 

IMG_0528.thumb.PNG.69bdd0498ae4ca8d62e770cd7ef7aec7.PNG

 

IMG_0529.thumb.PNG.4d580f96dcd5f8baf4dfd096b72e9563.PNG

 

 

 

The speakers presented OK for 45 years old, Drivers needed assessing with bass surrounds being the only visual issue. Someone before the previous owner had cut holes in the rear panels to access the crossover potentiometers and rewired them externally. A bit of research revealed this could be catastrophic as the design for the bass relies on the box being sealed, if the speakers have been driven hard the voice coil formers could have slammed into the magnets cracking the voice coils. 

 

IMG_0533.thumb.PNG.e7e54469daa89c5f3bf982719c9bf4fd.PNG

 

I gingerly fired them up and went through the motions of testing all the drivers at low levels, to my relief the bass drivers were fine, the mids were said to be bulletproof, and I was surprised that the tweeters were sounding sweet also. One potentiometer was broken but the other 3 did as they were asked without crackle or dropouts. 

I selected a vocal track and increased the volume and it was apparent what all the fuss was about, I had a poor source and an average amp but new these speakers were worth saving and setting up properly.

 

Bit of research and theses speakers were build cira 73 in Holland, having the removable grilles. Removed the drivers and crossovers, revealed that the tweeters had been replaced in 82

 

IMG_0552.thumb.PNG.6d62f0d9c194bbafef052fb1c2b27bda.PNG

 

IMG_0553.thumb.PNG.4d0fe7340070c0cb90b283698bfffb21.PNG

 

Sanded back the old lacquer and made a few repairs 

 

IMG_0554.thumb.PNG.c0432c87f16be797764541c5d3d854c6.PNG

 

IMG_0558.thumb.PNG.db25a052230a31cbdcc73a65cdd34997.PNG

 

One speaker had lighter timber beads to the front that needed staining to match the American Black Walnut veneer 

 

IMG_0557.thumb.PNG.5b4f36add78bf2009faee07144907c05.PNG

 

IMG_0559.thumb.PNG.6887cd80fb76b85db2b4e85e0b22f387.PNG

 

sprayed a couple of coats of 25% gloss acid catalyst lacquer, final coats this morning, happy with the results 

 

IMG_0560.thumb.PNG.c5dc5f81ad72749ed5f4361d7be043c1.PNG

 

IMG_0561.thumb.PNG.06ed48fa06762ad7c68cc3d0408b3dc4.PNG

 

IMG_0562.thumb.PNG.df7e7a93e706b6db344fb7a747de3821.PNG

 

began making new crossover boards today, I will be replacing the capacitors and adding L pad attenuators, swapping the terminal to gold bananas, hopefully the new bass surrounds arrive before Christmas. 

 

Al

 

 

 

 

 

Edited by Powerglide
Date correction

Share this post


Link to post
Share on other sites

Great work on the cabinets Al.  They look like new.

Share this post


Link to post
Share on other sites

Great work; and they should sound excellent when fully refurbished!

 

I bought a new pair of these sometime around 1970 and they were indeed superb for the time, and probably still very good when in good (or refurbished) condition. They were my introduction to quality sound. I took them to NZ with me and when I left I was able to sell them for the same price I paid--free listening for seven years!

 

 

Yes, the cabinets need to be sealed--these were one of the early acoustic suspension speakers (this construction was invented by the founders of AR) and the speakers depend on the sealing to provide the required suspension spring/damping. Without the cabinet the speaker suspension is very floppy. The lack of ports also makes them quite flexible in their placement. (I still prefer acoustic suspension speakers and find the SGR CX4F-2 delightful.)

 

BTW the ones I had did not have any beading around the front--so I would say the grill cloth was replaced earlier too.

 

Please keep us up to date on how it all goes. 😊

 

 

Share this post


Link to post
Share on other sites
30 minutes ago, GregWormald said:

BTW the ones I had did not have any beading around the front--so I would say the grill cloth was replaced earlier too.

Hi Greg, I joined an AR forum in New England, there's a real East/West -Love/Hate thing going on, ie. don't mention JBL, anyway they have all the answers on AR vintage and restoration. 

Your old ones with the thick front edge had fixed grilles and probably ply backs, were pre cira 73 and were built in Massachusetts. The later beaded model had removable grilles and were built/assembled in Europe, England and Holland, I still have the original grilles 

 

IMG_0526.thumb.PNG.9a4437a827cc9ecc56b342176e6a34db.PNG

 

I'm slowly getting all the crossover components together, just waiting on the L Pads from the US and some resistors for the mid range L Pads that apparently will make them perform more like they did off the factory floor. 

 

IMG_0563.thumb.PNG.8c08977db0ca2f6a6ec3e3b5c3442cab.PNG

 

if anyone is interested the original Potentiometers were 16ohm - 25w the new Attenuators are 8ohm - 15w, mids will run through a 25ohm - 10w resistor  

IMG_0570.thumb.PNG.bd78e24b44cf7b89afe82c096b9ca04f.PNG

New woofer surrounds arrived on Friday so I'm going to give them a crack tomorrow

 

 

Share this post


Link to post
Share on other sites


Posted (edited)

Had my first crack at replacing a set of surrounds. Nothing too daunting, a few you tube tutorials to get some pointers. Pretty basic, but still I learnt a little more about the music chain, nothing like pulling something apart to cement how it works.

 

46 year old crusty surrounds 

IMG_0591.thumb.PNG.7cb59a13599ae30b7ad751b657ffee38.PNG

 

removed 

 

IMG_0592.thumb.PNG.195de78ef15db7b1efd1e3374e867404.PNG

 

old glue removed 

 

IMG_0593.thumb.PNG.3758d1f46555125a58fb89ef6aa8d911.PNG

 

new surrounds fitted

 

IMG_0594.thumb.PNG.b1eef935214063482ca75ab39370db12.PNG

 

can recomend Queensland Speaker Repairs for these surrounds and the bostik glue they supplied was great and easy to use, but the applicator was a hassle, needed an extra hand to keep the glue flowing.

 

IMG_0605.thumb.PNG.2549e6c9704d7fbcde07a34f3858a060.PNG

 

I didn't use the shim method, coils aligned perfectly once the cones were glued. I probably didn't need to but I ran a tone generator through the speaker at 50Hz to double check. Can share the App if interested PM me.

 

 

 

 

Edited by Powerglide

Share this post


Link to post
Share on other sites

Progess on my refurb 

 

freshened up the faces with a matt black enamel chalkboard paint

 

IMG_0635.thumb.PNG.b3b63d82beed7acb6f00877899ec896a.PNG
 

because my pots had been savagely cut out from the rear I made complete new crossover boards from black acrylic. I have access to a digital printer so I took a photo off the net of the rear panel text and had it converted to a vector file for printing. I had no accurate measurements of the L Pad location but it looks pretty good

 

IMG_0638.thumb.PNG.ef9eaafc4405f25c4afb7273ea66fc3e.PNG

 

I put a matt laminate film over the vinyl sticker after I applied it to the acrylic

 

IMG_0630.thumb.PNG.1942e7d40a35b9c4a8a415260fac85cc.PNG

 

With the new L Pads installed apparently the mids perform more to the original with these resistors fitted 

 

IMG_0634.thumb.PNG.cef92b44880719364f4d57d36ac765ba.PNG

 

Finished off the cross overs

 

IMG_0632.thumb.PNG.8ef11e6ca6c345e558af9b46c8ed9263.PNG

 

IMG_0633.thumb.PNG.664eec7e9950dfb1027ccebca720a920.PNG

 

This design of AR's relies on a sealed box, I ran a thick bead of Sikaflex around the terminal opening to create a gasket 

 

IMG_0637.thumb.PNG.e61ea9cbbd9e0b7bb00d4c0597dc0b46.PNG

 

rear view 

 

IMG_0631.thumb.PNG.263ddaf29548e40e58c33b927dc080f3.PNG

 

IMG_0639.thumb.PNG.944b21552586422f234c5b021237c482.PNG

 

got to do a little trouble shooting on one of the bass drivers, everything else is working which hopefully means my first solider job is OK even if it's not that pretty 

 

 

 

Share this post


Link to post
Share on other sites

Brilliant work! You must have great patience.

They certainly look like they will sound incredible.

Cheers, Rob

Share this post


Link to post
Share on other sites

Thanks Rob,

 

had a little teaser today, I'm taking some flack files and a DAC in to work tomorrow, hopefully I can sort this woofer out and crank them both up 

Share this post


Link to post
Share on other sites


Sorted my Bass driver issue and restuffed the cabinets 

 

IMG_0647.thumb.PNG.0b4b7cf446632a98913aabf9672f891d.PNG

 

IMG_0645.thumb.PNG.3655c47f5f41a9bb654649da2da7ddbb.PNG

 

finally got to open them up and for what they are they sound great, the first thing you notice is the amount of bass they possess for a small bookshelf. 

 

IMG_0649.thumb.PNG.08af1754318856be0d7477a16987f92b.PNG

 

Looking forward to putting them against something else in a proper room with better gear.

 

IMG_0646.thumb.PNG.1beada69f368ed5c2542d2a8c9182ba9.PNG

 

super happy with the results, thanks to @evil c for his advice and original comments about these speakers that sparked my interest,@MGO for the cap selection's and candid comments about my lack of soldering skills, hey sometimes ugly can work too! 

 

Share this post


Link to post
Share on other sites

@Powerglide been watching your AR rebuild project with interest - haven't needed to comment as you have surpassed my level when I rebuilt my pair of AR2ax .

Credit to your dedication and professional manner, one of the best results I've seen! 👍

Share this post


Link to post
Share on other sites

Hi Al, I haven't really been on over Christmas/New Year and somehow completely missed the message you sent me earlier about these. Absolutely fantastic to see your restoration - the end result looks brilliant.

 

Really puts a smile on my face seeing them get the care they deserve.

Share this post


Link to post
Share on other sites

Thanks @Timepop surprisingly the most work, or should I say time, was in the research around getting the correct attenuators and understanding wiring the caps. It looks like pretty simple stuff but for a first timer there's still a few wires that could have gone wrong.

One thing that was a bit confusing is the bass woofer is wired reversed polarity to the other drivers, so the most basic rule is broken, negative is connected to positive inside the box. 

 

Ive had them home now for a few weeks and it took a few different line ups to get the best out of them. Maybe the mids and tweeters have deteriorated somewhat but I found it hard to get some life out of them with my mainstay vinyl set up, they are heaps brighter through digital. I have 3 Amps, two TT's and two Phono stages so plenty of combo's later and the best for vinyl was 

 

Ortofon Rohmann with ruby cantilever - Sansui SR525 - Exposure XXVI - Cambridge Audio Azur 351r 

 

They are definitely a great listen, and when you dedicate an entire evening to them they have moments of brilliance, they perform well with blues and vocal tracks, they especially like layered seventies soft/folk rock, Steely Dan, Little Feat, Allman Brothers, Fleetwood Mac, CSNY ect. 

I find them a little too polite for heavier rock and the separation is not quite there for Floyd and detailed modern recordings, which is why I think the mids and highs could be a little fatigued (not that I've ever heard another pair) All that said I could easily live with them but for a set of 4313b's prowling in the background, not that there was a contest but even my listerning companion agreed the JBL's are from a different league. 

 

IMG_0664.thumb.PNG.3aa2d156ba8f2c0e5ff87f555f2697ac.PNG

 

IMG_0663.thumb.PNG.27cf5059e3e72c7bbb418bc5dea986ca.PNG

 

 

 

Share this post


Link to post
Share on other sites


@Powerglide I’m speechless, that is “beautiful work” you did there and your photography is to be commended too.

This thread put a smile on my face for sure, Thank you 👍

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...