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isupreme

Restoring AR 93 speakers from my youth

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Hello to the Forums!

I have been reading related posts and look forward to hearing from you all about my project.   This will be a minimal/low cost restoration.   My main issues seem to be the tweeters  and the wood material which is shedding.   A friend came by and we ran sound tests at different frequencies.   It sounded good except the tweeters.    I am trying to keep my costs and efforts down, and i will probably not replace the crossover unless someone convinces me it has to be done.

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INFO and Questions : 

I always called them AR 93.   But i see a lot of talk about 93a  and 93q etc.    Do  i have just 93 or something else?

   A long time back i put in some crappy tweeters.  Time to put in the right replacements.    How do i find the right tweeter?   I see some for sale that say they are AR  -  are they really?  how can i KNOW i am getting the right tweeter. 

             The cabinet boxes are shedding ALOT.    Each time i brush off some crap sticking up - there is more.   I need to find a way to lock the wood down so i can sand it.   I am currently considering painting them with an oil based primer - and then sanding them some and repaint again and again.     Suggestions welcomed.   The variations in shape do not really bother me - i just want to stabilize the situation and put the socks back.

           The mid and bass speakers look pretty good.  But!  In the past replacements have been done.   I think i have two original and two replacement bass speakers.  Of these two styles which do you think is the original?      In the picture, the near one which is solid black with a rounded cone.  ( somewhat crumpled)   OR  the far speaker pictured which shows a tan paper center.  Right now each cabinet has one of each. 

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The story  :    Man i love these speakers.   I was a teenager working in a high end fidelity store.   The store manager was nice to me and helped me get set up with these and some very fine Kenwood mono amps.   Many hours of joy listening to records.   I enjoyed these speakers so much that i was truly bummed when digital music came along.    The loss of 3D sound qualities was hard to accept - although like everyone the convenience caught me.

Between the rise of digital and some troubles with the tweeters, these awesome speakers have been missing too long from my life.    My goal is to get them working well and then buy the proper equipment to drive them. 

 

Thank you for any input.

 

speakers rebuild.jpg

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The visible woofer and the tweeter in the foremost enclosure are not AR drivers. 

The two 8" midrange drivers appear to be original.

The cabinet material is a type of particle board, so it won't really sand, as you've described. 

It was originally painted a matte black, so you could do that again, using a good primer for its adherence quality. 

The drivers should be removed before you do any cabinet work, and you'll also be able to get a good look at the crossover, and replace any capacitors as needed. Plenty of members can help you with crossover advice.

Once the drivers are out, take some photos, including any printed part numbers, so we'll know what you're working with. Good luck!

 

 

 

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Welcome isupreme

You'll get plenty of help here. btw, do you still have the Kenwood mono amps?

I'll be following this with interest. I've worked on the 91, 92 and 94 but never the 93.

If you haven't found this page already, here are brochures and info for the 9 series: http://www.classicspeakerpages.net/library/acoustic_research/ar-9_series_1978-1981/  Based on what I see there, it looks like the 93 and 94 used the same 32mm/1.25" liquid cooled cone tweeter. Maybe some others used that tweeter. Hoping a member will come up with a part number. As for the 200mm/8" woofer I suspect that was common to many AR speakers and shouldn't be hard to find. As ar_pro said, take pics of the printed parts numbers on all the (original) drivers and that will help you find replacements. Did you replace the foam woofer & mid surrounds? They look OK in the pic.

oops. Just lost my edit. The gist of it was; if you look at the 9 series brochures I "think" the tweeter was the same for the 93 and 94. Pic of a 94 tweet below. I think these are fairly common but I don't have the PN. There are a couple of AR-94 tweeters on ebay for about $40 each.  If you are unable to get the correct tweeters, one CSP member recommended these: https://www.parts-express.com/dayton-audio-dc28f-8-1-1-8-silk-dome-tweeter--275-070

The 8" woofer and "mid" in the 94 are the same. AR part # 1210067-08 272TNG (the 272TNG indicates made by Tonegen).

Kent

94 tweeter.jpg

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Hi isupreme these are not original replacemement 15222064633511596960167.thumb.jpg.1930975ed85345020968c7b2b6a54757.jpgdrivers but I am very satisfied with the sound 

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nefertem,

What are they? Are they the Dayton Audio DC28F-8 1-1/8" Silk Dome Tweeters?

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Hi JKent Vifa tweeter and scanspeak midbass classic from Madison sound

Ps I just picked up a luxman hybrid intergrated amp 105u and it really opened up the bass even when I had these speakers new all my other components could not perform like the luxman 

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Good Job ❤🥰

What are you using to drive them?

One thing I used to experiment with was putting small books under the front when I had the original drivers in the speakers 

After Dr frankenspeakers finished his operation the soundstage was more forward 

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I have maybe 3 of those AR tweeters in excellent condition that I have no use for. All harvested from AR94 cabinets.

PM me if you're interested.

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The original model numbers for the AR-93 woofer, midrange and tweeters are:

200035 - woofer

200036 - midrange

200034 - tweeter 

The 210035, 210036 & 210034 are the same as the above, but manufactured by Tonegen for AR.

Note that the AR made a 200038 tweeter that has the same specs as the 200034, but with different metal work.  I would note recommend mixing the two, but it looks like either model will work. 

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Thanks for the welcome and responses.

ar_pro   thanks for the speaker ID

j kent.   I wish i still had those amps. I  they were great and i can't believe i ever let them go....   I will have to find an affordable amp to make this go.

Nefertem     a tweeter option.  nice.      re: putting books under.    When my friend and I tested these out we found a big difference from on the floor to raised up some.  We also tried them against the wall and 3 foot in front of the wall.     Each change altered the bass in different ways.

          I wonder if these were designed to be place right in front of a wall?   Seemed like it.  

David R.. msg in your box  :)

AR 55    good info, TY.    Yes in fact those are the numbers i am seeing now that i have them out.

Today's big Question.     Opinions on the two replacement woofers I have  ?     They seemed ok to my old man ears, but i would like to KNOW that i am rebuilding a true fidelity sound as sometimes that confidence is pleasing.

RE: Crossover.   I just want to skip this.  But maybe you all should talk me into dealing with it.    When we ran different frequencies during the sound check, the speakers seem to work well.    The soundstage presence is working well.      I have done some soldering and so its not the end of the world to do, but it is a bit over my head.

 

drivrs out.jpg

speaker replacements.jpg

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The replacement car stereo woofers won't be the same as the original AR drivers.

As per AR55's information, you'd need a pair of the 200035 or 210035 (Tonegen) 8" woofers to bring everything to spec.

There is a pair of "tested & working" 200035 woofers currently on eBay, at about $100/each.

Don't fret over the crossover -  this sort of soldering is very easy, and you could teach yourself how-to with a YouTube video with maybe an hour's practice. If you did any work on the crossover, it would just be to replace three small capacitors, as everything else should still be just fine.

Prior to painting or doing any crossover work, it would be a good idea to remove the polyfill stuffing into a pair of trash bags. Wear a mask, as it will put particles in the air.

Here's a link to an AR-93 restoration page, with helpful photos & schematics:

https://www.audiovintage.fr/leforum/viewtopic.php?f=20&t=59580

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I may be pilloried here but if those Nippon America woofers sound good to you for the side-firing woofs, leave 'em. If the crossovers seem OK, leave 'em (but I'd replace them if they were mine).

I'd go with original tweeters but there are options. Once you put in Dayton or Vifa tweeters these will no longer be AR-93s but if they sound good to you, what the heck. OTOH, you won't KNOW they sound good until you buy the tweeters and install them. Then it's too late. DavidR's offer is a no-brainer. I bought a preamp from him and it was very nice, at a fair price. Why take chances with wrong tweets or ebay pig-in-a-poke?

Those speakers probably like power. One option (of many) would be a Crown like this https://www.amazon.com/Crown-XLS1002-Two-channel-Power-Amplifier/dp/B011TI97VE/ref=sr_1_5?dchild=1&keywords=crown+xls&qid=1594674869&refinements=p_85%3A2470955011&rnid=2470954011&rps=1&s=musical-instruments&sr=1-5  Gobs of power, brand new, low price. There are similar amps from Behringer and QSC. For my 91s I use an Adcom 555 II and the aforementioned Adcom 565 but I had both checked out by a pro before putting them into service (both were fine btw)

Kent

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On 7/13/2020 at 5:14 PM, ar_pro said:

Don't fret over the crossover -  this sort of soldering is very easy, and you could teach yourself how-to with a YouTube video with maybe an hour's practice. If you did any work on the crossover, it would just be to replace three small capacitors, as everything else should still be just fine.

Yeah--looks like just 3 electrolytics. 4 decades old. I'd ditch 'em.Lowest cost: Buy 2 of these https://www.erseaudio.com/Products/PEx250v/4uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor   and 6 of these  https://www.erseaudio.com/Products/NonPolarElectrolyticAll/ANP10-05-60-0-PB  (put two 60uFs in parallel to make 120uF)

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Those ERSE npe are really low end. IIRC Roy ended up saying he no longer would recommend them.

I've measured many brands of caps for ESR, CAPACITOR DISSIPATION FACTOR/QUALITY FACTOR/PHASE ANGLE. ERSE  measure the worst, Parts Express/Black Beauty measure the best.

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2 hours ago, DavidR said:

IIRC Roy ended up saying he no longer would recommend them.

I don't think so. Roy can speak for himself but I'm sure he has no objection to Erse. One reason I recommended them is, besides the low price, they actually have 60uF. Finding 60 and 120uF ain't easy.

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1 minute ago, JKent said:

I don't think so. Roy can speak for himself but I'm sure he has no objection to Erse. One reason I recommended them is, besides the low price, they actually have 60uF. Finding 60 and 120uF ain't easy.

Hi Kent,

Given the availability of the clearly superior Parts Express and Bennic electrolytic caps, I stopped recommending the Erse NPE's some time ago after, like David, doing some basic tests and dissections. :) I frequently work on cheaply made old speakers, and I wouldn't have a problem using an Erse electrolytic as a repair part for the really crappy 35v capacitors found in many of these...but there is really no compelling reason to choose them when better electrolytic caps are readily available.

There were some negative comments made along the way in the forum about Erse film caps. I don't have a problem with any of those.

Roy

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that explains my confusion. I have only used the Erse film caps, not the electrolytics.

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When checking film caps of the same size and different brands they all measured very much the same, except for maybe ESR having some differences BUT not huge differences. I found the Clarity had the higher ESR values.

MDL measured better than Bennic but I hate their very thin leads that come on even the large value caps. Bennic have become hard to find lately.

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Still hard to find the 60 and 120uF electrolytics. PE has neither value. You'd have to cobble them together using 50 + 10 and 100 + 22. It would be even more of a challenge at Madisound. Maybe an MDL 125 for the 120, or parallel an MDL 100 'lytic & 20 film. For the 60, maybe 2x31 or 40 + 22. No simple solution. That's why I suggested Erse. If the Erse 'lytics aren't great, there's this 62uF film: https://www.erseaudio.com/Products/PEx250v/62uF-250-volt-Metallized-Polyester-Mylar-Film-Capacitor for $7.29.

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While painting the cabinets today i saw the sticker on the bottom  - they are 93Q.

Does the crossover age due to use or time?   These speakers have been sitting around a long time.

What would i hear that would indicate they are not working well?

I am sorely tempted to put in new drivers and roll on... but....

does this look like an original crossover?

speaker crossover.jpg

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39 minutes ago, isupreme said:

I am sorely tempted to put in new drivers and roll on... but....

does this look like an original crossover?

Yes original.  Those look like Unicon caps and they are probably still good.  It could be worth it to listen  before you replace.  Replacing caps can be a low payoff activity. 

Adams

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26 minutes ago, Aadams said:

Yes original.  Those look like Unicon caps and they are probably still good.  It could be worth it to listen  before you replace.  Replacing caps can be a low payoff activity. 

Adams

I agree. Those 80's Japanese capacitors actually held up quite well. Give 'em a try.

Roy

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A friend came over with his sound equipment.  We ran different frequencies and everything seemed ok....    It was a pleasant surprise to hear them crank at 40hz. 

Its amazing how much lighter the cabinets are without the speakers/magnets.  

The cabinet wood responded well to the first layer of paint.   It really did a good job of binding the wood.   I can now do some light sanding and another coat - then color.    I don't know if the pictures show it well, but the surfaces are REALLY rough.   In some areas the material just fell apart.   From what I am seeing it is very apparent that the wood is falling apart because ultra violet light has destroyed the glue holding the wood particles together.   The sides that would have seen window light are the most damaged, and inside where the light does not go there is very little.     I could do some bondo  work to bring back the edges but since I am lazy I will hope the sock covers these sins acceptably.1401661332_firstpaint.thumb.jpg.f60aeb5a9d87e66a000ce07bc3ed0f05.jpg

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