Jump to content

Help Identifying AR3? AR3a


danacook88
 Share

Recommended Posts

I came upon a pair of AR-3s, a single AR-2ax and a single AR-2a.  Attached are photos of the unfinished pine cabinets of the AR-3s as identified via the label on the back of one of the pair, serial number 24257.  The second does not have the model label.  My question is regarding the drivers.  It seems from what I can gather, that the 3 mainly had the Alnico woofer, but these have the later version installed.  I had the skivers professionally replaced and the gentleman also inspected the spider, VC, and tested with o-scope.  Same with the pair of cloth surround ten-inchers from the 2-models - resealed, and rebuilt one of the VCs.

The mids look correct.  The tweeters have three orange-ish "nodes" and I believe are the 3/4 inch model.  From poking around on the interwebs, it seems to me that these should have the 1.25 inch tweeter which has four orange-ish "nodes."  BTW, the AR-2 models that I have deploy the latter tweeter.  

Additionally, any input on the following would be helpful as well.  The front "picture frame" bezel has been removed so that the front face is flush with the inner frame that would have supported or at least limited the grill's descent towards the drivers/baffle.  I have mixed feelings about covering up the original, in this case, non-finish, but I have some rudimentary woodworking skills and would consider applying a walnut veneer with a solid walnut "picture frame" bezel to replace.  Thoughts?  And, in anticipation, does anyone know the depth of that bezel?  I believe it is also rounded from what I could gather from photos.

Thank you in advance.

Dana

 

ar3 - 1.jpg

ar3 - 2.jpg

ar3 - 3.jpg

Link to comment
Share on other sites

Hi dc88, and welcome to the CSP forum. There are members here who are experts with the "3" series models, but I'll offer a few first thoughts.

You've mentioned that the one paper label with s/n shows an AR-3, but by all frontal appearances those appear to be AR-3a's. Tweeters are definitely the 3/4" dome; mids appear to be from early front-wired AR-3a (A.11 version shown on p.29 of restoration manual?); and foam woofers certainly look like one of the 3a variants. It is always possible that various AR drivers have been installed in AR-3 cabinets, but you really won't know what's going on until you lift the woofers and take a look inside at the crossovers - - the AR-3 and AR-3a have identifiably different crossover components - - and this may help your understanding of the history of these speakers.

The unfinished pine cabinets have become highly sought after by some collectors, and with this cabinet option, the front face moulding was fabricated from solid birch. The (rather poor) pic attached shows the profile from an old AR-3 walnut moulding, but you can begin to get an idea of the profile. I've also included a rough sketch of the approximate cross section dimensions.

Knowing that your "2" series speakers have the same woofers and tweeters, you can probably consider them as a reasonable "pair" for stereo use despite the different mid drivers found in the 2a vs. the 2ax. Show us some more pics of these and the insides of the 3's when you can, and you'll get the best advice.

AR-3 moulding pic.jpg

AR-3 moulding.jpg

Link to comment
Share on other sites

Thank you for the guidance, ra.ra.  What you describe is what I was thinking - 3a drivers in a 3 cab.  Were the crossovers the same between the 3 and 3a such that this could be done without issue?  I will get photos of the innards Thursday as I have obligations tomorrow and evening.  

Same with the 2 models - photos to come.  I have not fully tested them at this point.

Currently, the 3/3as are set up as mains in my living room in place of my Allisons.  Very musical indeed.

Link to comment
Share on other sites

Apologies, ra.ra.  Forgot to ask.  The dimensions of the profile are wonderful.  Since it is not rounded but just an angled cut will make this endeavor much easier.  If I am interpreting this correctly, the lower "tongue" that has a width of 1 7/16 inches would be the flange that supports the grill.  Therefore, the portion that I need to replace is actually the upper 11/16 of an inch.  Am I interpreting this correctly?

Again, many, many thanks.

Dana

Link to comment
Share on other sites

Other members with more experience will chime in, but if I were attempting to create this face frame for new grilles, I'd be inclined to simplify the profile and rely on velcro or friction-fit to hold the grilles in place. I believe the old AR-3 grilles were held in place only on the short ends - - - hence the deep reveal as shown. Your question about the 11/16" portion is a good one, but since it is difficult to tell from your pics what the relationship is between the clear flat frame and the inset black perimeter subframe, I cannot offer specific dimensional feedback. You want the grille fabric to sit just behind the perimeter frame while still clearing free of the protruding driver parts. In any case, if you want to restore these, I'd suggest removing that thin (1/4" thick?) clear face frame, mill up some new thicker frame stock (similar to profile shown, but without dado reveal), and then fit these new pieces (with miters) to the original side panels for the intended "picture frame" effect.

 

AR-3a frame.jpg

Link to comment
Share on other sites

21 hours ago, danacook88 said:

The mids look correct.  The tweeters have three orange-ish "nodes" and I believe are the 3/4 inch model.  From poking around on the interwebs, it seems to me that these should have the 1.25 inch tweeter which has four orange-ish "nodes."  BTW, the AR-2 models that I have deploy the latter tweeter. 

Dana

Dana,

Your specimens appear to be factory AR-3 to 3a conversions. The tweeters and mids are consistent with the serial number you provided (early 3a), but it is likely the original cloth surround/alnico magnet woofers were replaced by someone along the way.  The AR-3 and 3a crossovers are quite different, and the crossover boards would have been replaced as part of the conversion.

The AR-3, 2a, and early 2ax shared the larger tweeter.

Roy

Link to comment
Share on other sites

Attached are photos of the interior in reply to ra.ra.

RoyC - easier news with regard to crossover-component compatibility, etc if this was a factory conversion.  

ar_pro - Not to my taste as I love love love black walnut, oiled, but I can understand the allure.  Those are also unfinished pine.  I intend on repairing the framing and then sand.  Then, go from there.  

d

 

ar3 - 2 (1).jpg

ar3 - 1 (1).jpg

Link to comment
Share on other sites

Dana,

You have the first version of the AR-3a crossover. The large coil with the number "7" written on it was used with the earlier woofer...which you no longer have. You can add a 1mh coil in series with this coil, or replace it with a #9 coil (2.85mh) for your later woofers to perform as intended.

I edited your photo to show the easiest way to go, by the addition of a 1mh coil.

Roy

5942b8d48493d_ar3-1(1).thumb.jpg.b0b383230354eeb58391d4749cba6f40.jpg

Link to comment
Share on other sites

  • 2 weeks later...

The original grill frames were plastic, and would bow out so you could remove or insert the top and bottom so they would slide into the slot. Later 3a grills just fit flush and the frame molding had flat inner edges.

I recently restored my 2nd set of 3's, and made new grill frames using 1/4 inch MDF. They are cut to size to fit flush with the molding edges, and the Saran grill cloth adds enough added thickness to make them fit nice and snug, but can be removed easily if needed.

Glenn

Link to comment
Share on other sites

Attached are measurements of each speaker - right only, pink noise - left only, pink noise - 6 inches from front baffle, sliding up and down in a "skinny" ellipse.  I used the average setting in AudioTools on my iPhone 6 with internal mic (too lazy to grab my iMM-6 mic).  The one that was averaged for 19 seconds at spl = 94.9 is the speaker with the smooshed tweeter as can be seen in comparative results with the other.  

RoyC, the woofer response does not seem too bad.  I purchased the inductors but have not yet made the change.  Thought I would measure first and compare.  Would I expect woofer output to increase, decrease or the change is not about amplitude to flatten FR?  Thanks in advance.

Thank you very much, Glenn for letting me know about grills.  

All - Never had a fully functioning (less partial tweeter) ARs in house.  Weeks now with them up and acting as mains in living room.  Very understanding wife...

Regards,

dana

ar3 - 2 (2).jpg

ar3 - 1 (2).jpg

Link to comment
Share on other sites

On 6/28/2017 at 6:04 PM, danacook88 said:

RoyC, the woofer response does not seem too bad.  I purchased the inductors but have not yet made the change.  Thought I would measure first and compare.  Would I expect woofer output to increase, decrease or the change is not about amplitude to flatten FR?  Thanks in advance.

dana

It should slightly reduce the woofer's output beginning around 500Hz, and result in a cleaner transition to the mid.

Roy

Link to comment
Share on other sites

  • 1 month later...

And, so now, I understand the need for the reduction in woofer output.  In the room, the output is significant.  For those that prefer such, then great.  If not, it can overload the LF response.  Thank you again, RoyC and others.  I am going to complete a redo on one of the facia as it did not come out as well as desired.  And now, I have a pair of AR-2/2a/2ax mix and have questions.  But first, a search.

Link to comment
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.

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.

 Share

×
×
  • Create New...