AR-4 series speakers

[ligs]

Yes, I modified both AR4X with the crossover described in # 19. Initial impression was they had very smooth midrange which made voice and strings very listenable. The highs were very extended with just a touch of sibilance on some programs. The bass was very robust even when the speakers were off the ground and away from back wall. Subjectively they had a broad peak around 70-80Hz which gave a nice and pleasant foundation to many program materials. See the following graph for the elevated bass range.

http://audio-database.com/AR/amp_speaker/ar-4x-e.html

[RoyC]

Thoughts, anyone?

Those are probably standard AR-4xa's. The response of the AR-4x cloth surround woofer was not all that different from later foam surround 8 inch AR woofers. There is no way AR would have used the AR-4x crossover with the 4xa tweeter...much too low.

AR had manufacturing facilities in Europe. Cabinets varied somewhat.

Roy

[ra.ra]

Hey ligs, I enjoyed your last post because I learned a new word (sibilance) and, while my own foreign language skills are most unimpressive, I do get a kick out of the strained syntax in the Japanese translation from your attached link.

One more question about your cap value. In post 18, you seemed to make a calculation of sorts to determine the 8 mf value that you used, but in post 21 you seem to agree with HarryM that maybe a 10 mf cap would be a better choice in order to more closely replicate an original 4xa crossover. Did you decide on 8 mf because of your calculation or because that's what you had in the parts drawer, and, do you think a 10 mf cap would be a more suitable crossover change with this newer tweeter?

And Roy, thanks for the response, but I think perhaps my long-winded comments obscured the point I was trying to make and the question I was trying to pose. Forgetting about my inconsequential comments about the grille badges and the walnut veneer and the cloth woof surrounds, I was trying to make the point that I'd never before seen an AR-4xa with the rheostat tweeter control, but you seem to be stating that this probably constitutes a "standard" 4xa speaker. From what little I know about the 4xa, that has not been my understanding - - - I have only seen the switch controls in the 4xa. My interest in pointing this out can be found in my original post 1, where I expressed thoughts about converting a pair of 4x's into 4xa's while retaining the original A-P pot control.

Regarding my ill-formatted question, after trying to understand how ligs arrived at an 8 mf cap value for his hybrid experiment, I was pondering whether I might be served better - - - in my attempt to convert 4x's into 4xa's - - - by simply dropping in the new 1-1/4" tweets (with adapter rings) and reducing the capacitor from 20 mf to 10 mf. Is it conceivable that I could expect this reconstruction to perform similar to a factory assembled 4xa speaker?

[RoyC]

And Roy, thanks for the response, but I think perhaps my long-winded comments obscured the point I was trying to make and the question I was trying to pose. Forgetting about my inconsequential comments about the grille badges and the walnut veneer and the cloth woof surrounds, I was trying to make the point that I'd never before seen an AR-4xa with the rheostat tweeter control, but you seem to be stating that this probably constitutes a "standard" 4xa speaker. From what little I know about the 4xa, that has not been my understanding - - - I have only seen the switch controls in the 4xa. My interest in pointing this out can be found in my original post 1, where I expressed thoughts about converting a pair of 4x's into 4xa's while retaining the original A-P pot control.

Regarding my ill-formatted question, after trying to understand how ligs arrived at an 8 mf cap value for his hybrid experiment, I was pondering whether I might be served better - - - in my attempt to convert 4x's into 4xa's - - - by simply dropping in the new 1-1/4" tweets (with adapter rings) and reducing the capacitor from 20 mf to 10 mf. Is it conceivable that I could expect this reconstruction to perform similar to a factory assembled 4xa speaker?

AR made many changes on the fly. The cabinets are labeled AR-4xa, and do not look to have been tampered with. It is entirely possible that the early 4xa had pots and the 4x cloth surround woofer. Changing the 4x cap to the 4xa value and replacing the 4x tweeter with the 4xa tweeter = an early AR-4xa...assuming AR didn't play around with the woofer inductor as well.

Roy

[ligs]

As to why I stayed with 8 uf for the high pass, it turned out I liked the sound of this configuration right from the beginning. Also from the crude measurement in previous posts the frequency response seemed to be flat from 1600 Hz and above and the entire treble band is just a smudge lower than the woofer thus retaining the traditional AR sound.Another thing I liked about this hybrid AR x was the great detailed throughout the bass range. Typically a larger woofer could produce more or deeper bass but not necessarily more bass detailed! I am impressed by this little AR 4x woofer:)

BTW, the 1 1/4 inch tweeter is also a top class tweeter, not as bright as the 035Tia used in JBL 4406 monitors but has good details as any dome tweeters I came across.

[genek]

I hope in the next few weeks to work up a 4x mod with phenolic ring tweeters and a new xover. Will share the results when complete.

You can call it the "AR-4xb"

[ligs]

To be fair I probably should call it "AR-4-18" acknowledging the tweeter is from AR 18. I am more a tweaker than a refurbisher and there is a lot more fun trying something new(within reasons of course). To think about it even recapping should be called tweaking not refurbishing:) Long time ago I turned my AR3a's into AR11's by replacing the tweeters and crossovers even winding my own inductors (something like 70 turns on an one-inch bobbin).

[ra.ra]

Thanks .... all good and interesting responses from everyone.

RoyC's speculative comment tends to confirm my recent thoughts - - - that perhaps the 4xa example shown may have been an early release, a youngster, a newbie, in the transition period between the last of the 4x and the full production changes to the 4xa. That theory would reasonably explain the points raised in my curiosity - - - the pot control (not a switch), the square grille badge (not rectangular), and the cloth woofer surround (not foam). And since my 4x's do have the #5 coil which is consistent with all I've seen with the 4xa, I feel I can eliminate that component as yet another potential variable.

The comments from ligs about tweaking vs. refurbing are fun to read and give me more impetus and confidence to experiment a bit. Regarding the cap value, I am currently more inclined to begin with a 10 mf cap for two reasons: 1) I happen to have some fresh 10 mf caps on hand slated for an AR-6 restoration; and 2) this more closely recreates the original 4xa crossover, which has been my stated objective. However, the 1-1/4" tweets I have on hand are a bit of a mish-mash and I'm not certain which I will try first or which may work best. I have four tweets of this general type: (1) p/n 200005-0; (1) p/n 200014-3; and (2) p/n 200038-0.

And genek's comment reminds me - - - with respect to a 4x mod project, what is Carl cooking up in his sonic laboratory?

[Carlspeak]

I'm still working on the PRT mod, but repair jobs keep getting in the way. Thanks to Kent I've be able to establish base line measurements using a borrowed pair of original 4x tweeters. At this point, it's clear that not all PRT's are the same. More to come. :-)

[WAROFMAN9]

I have a pair of AR4ax that have a three way switch and mismatched woofers.It looks original all soldered and looks factory.

AUdio Karma states that the switch is a S1 is a three-way (on-on-on) miniature toggle switch with sealed terminals and silver-plated contacts, C&K 7211SYZSQE or Alco MTA206PA04, available from Newark, DigiKey.

However, I can not locate this switch.

The original Switch is Carling MEXICO 6A125 VAC 3A260 VAC 1/4 HP120-240 VAC. I haven't figured out how to attach images.

I intend to re-cap 10uf and replace resistors (2 ohm 10w) but feel that the switch is the problem,

Suggestions for switch and how to determine if (on on on) is the correct configuration.?

[WAROFMAN9]

Attached Images of switch crossover & mismatched woofers AR4ax

[RoyC]

Both woofers were used in the earlier AR-4x model. They should work fine.

What makes you think the switch has a problem? They are not typically troublesome, as the previous pots were.

Roy

[WAROFMAN9]

No real evidence pointing to switch.. however no change noted as I change position.

Just thought I should replace everything. maybe switches are not necessary.

Also the two speakers had different sound levels...

Did the "listen with paper tube" test... no tweets...

How to test (battery) tweets?

[RoyC]

As much as many AR purists would like to believe otherwise, the AR-4x did use different woofers, and the response did vary somewhat. The overall sound should be acceptable once you get everything going, but there are a variety of 4x woofers floating around out there if you want to try for an exact match. (I believe I have one that matches the one shown on the left side of your photo.)

You really can't determine a problem with the switch if the tweeters are not producing sound at all. Assuming you do not have a multi-meter to test them with, scrape the paint off the tweeter terminals and, with your woofers disconnected, touch your speaker leads directly to them at low volume for a very short duration. If you get sound, the tweeters are working. No sense worrying about the switches if the tweeters are dead.

I'm betting your switches are OK. It is more likely a resistor rather than the switch, IF the problem is associated with the switch arrangement at all.

Roy

[WAROFMAN9]

OK, scrapped black paint off top of tweets ,Tested with source leads. Low - Mid volume... no response.

So, seems that replacing 2 caps & 4 resisters might fix crossover.

Suggestions for drop in replacement tweeters or is that committing AR heresy?

A question on the tweeter arrangement... why the rather complicated oval hole that the leads go over and through the cabinet?

Solen 10uF 400V Polypropylene Capacitor

Dayton Audio DNR-3.0 3 Ohm 10W Precision Audio Grade Resisto

rick

[RoyC]

OK, scrapped black paint off top of tweets ,Tested with source leads. Low - Mid volume... no response.

So, seems that replacing 2 caps & 4 resisters might fix crossover.

Suggestions for drop in replacement tweeters or is that committing AR heresy?

A question on the tweeter arrangement... why the rather complicated oval hole that the leads go over and through the cabinet?

Now that you have verified the tweeters are dead, it is doubtful the switches or associated resistors are bad. Of course there is no harm done in replacing the resistors, but it is very unlikely you will actually improve anything by doing so.

Since you are shopping at Parts Express, PE's Dayton caps will serve your purpose as well as Solen. The best bang for the buck, imo, is Madisound's 10uf "surplus" film cap.

There are no drop in replacements for that tweeter, so even if you can find one to fit the cabinet hole, it will not sound as intended. The good news is front and back wired versions of the tweeter were used in lots of AR models. It shows up frequently on Ebay.

Up until the mid-70's many AR tweeters were front wired. It made it easier to replace the tweeters without breaking the cabinet seal (or "acoustic seal" as AR called it).

Roy

[ra.ra]

I was just about to reinforce a couple of Roy's statements when I now see that you have begun some testing of your own. I agree that you first need to establish whether the tweets are still functioning, and I am also in agreement that there are several varieties of the 8" cloth surround woofer used in the 4 series - - - attached is a pic of two pairs of my 4x's, and the two pairs have different woofers which are similar to your mis-matched pair. In this other ongoing thread, you can see a third type of cloth woofer found in the 4x speaker.

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7798

Several varieties of this 1-1/4" tweeter were found in a handful of AR speaker models into the early 80's, I think, and I believe they all should work in an 8 ohm speaker like the 4xa. Later versions of this tweeter had increased power capacity with ferro fluid, and those are most likely all rear-wired and may have solderless connection terminals. I've never liked these front wired versions myself because they seem so delicate and exposed (even with the lovely electrical tape) when everything else about the speaker build quality is quite robust.

I'd agree that your best option is to find a pair of similar AR tweeters if you are certain that both of yours are indeed dead. That's too bad, they look just fine in your pics.

[WAROFMAN9]

Well inexplicably (as they do look untouched) I believe them dead.

Meter shows open. Can I move forward and replace crossover components while I look for tweets?

Kindof paid to much for this set because they looked in great shape...bought with no test...

thanks both for the help.

[RoyC]

Can I move forward and replace crossover components while I look for tweets?

I don't see a reason not to unless you plan on selling the speakers. There is generally not much interest in the AR-4xa model, but AR-4x woofers (all versions) are always in demand.

Roy

[ra.ra]

I have used both Dayton and Solen caps successfully with AR speaker restorations, and I now have two projects currently in progress where I plan to try these 10 uf surplus caps from Madisound. You've got several good choices here.

I happen to love this 4 series of speakers for several disparate reasons: sentimentalitity (my very first real speakers), size and proportion, and value (sound quality vs. cost). Roy is correct in noting that there has never been all that much interest in the 4xa, but that mostly had to do with a very poor marketing strategy by AR when they were trying to sell three different compact two-way models with 8" woofers and the very same tweeter. The lack of interest had little to do with the inherent quality of the 4xa speaker.

In fact, because I have several pairs of speakers from the "4" series, I am attempting to convert one pair of 4x's into a reasonable facsimile of a pair of 4xa's, by swapping out tweeters and adapting the crossover network.

Almost forgot to ask - - are your speaker cabinets real wood veneer? They appear to be the birch veneer that has been stained to resemble walnut. My advice: be patient, and try to find some new tweeters that will work.

[WAROFMAN9]

Appears to me as walnut veneer.... dark fine even grain. Explain what PE Phenolic Ring Tweeter 8 ohm will do to these speakers.

I read "harsness" etc may result...can this characteristic be tamed with Xover mods?

While I would like to retain original AR sound ( and parts) I guess I am wary of buying used and possibly questionable tweeters when mine look great and are inoperable.

rick

[JKent]

Almost forgot to ask - - are your speaker cabinets real wood veneer?

The photo of the label in Post #36 says "walnut grained" so I'd say plastic (vinyl).

Hate to say this, but maybe the thing to do with these is sell the woofers and buy some AR-4x's or other worthy speakers. I'm not a fan of parting out, but the tweeters are both toast and the cabinet is not wood. IMHO the only good stuff here are the woofers.

Kent

[RoyC]

Explain what PE Phenolic Ring Tweeter 8 ohm will do to these speakers. I read "harsness" etc may result...can this characteristic be tamed with Xover mods?

Rick,

The PE tweeter will not even fit in the 4xa cabinet hole, much less sound very good. It is peaky and harsh compared to the tweeter original to the 4xa.

There has been some experimentation using the PE tweeter in the 4x with 4x crossover mods, but not as a replacement for your tweeter.

My comment earlier was not to imply the 4xa is an inferior speaker, as it is essentially the same as the respected AR-6 and AR-7 models in a different cabinet, but it has never been an easy model to sell, yesterday or today. Honestly, if you want the project to be worth the effort and expense your only option (other than parting these out) is to find some used AR tweeters.

Roy

[WAROFMAN9]

OK then. Guess I made a less than optimal purchase here.. I have AR94,s for main listening room.

Purchased the 4s for office system.

Nice walnut Wood veneer cabinets / correct size for room. Definitely not plastic.

Have a marantz 2226b to drive them.

What specific AR tweeters should I look for?

[RoyC]

What specific AR tweeters should I look for?

There were basically two versions of this tweeter. The one used in your 4xa's (as well as the AR-6, 7 and 8) has a slightly smaller magnet than the other. But all versions will work satisfactorily. They all have the same appearance and same faceplate dimensions, but the early ones are front wired. Your AR-94's use the back wired version of this tweteer with the larger magnet.

"Walnut grained" means vinyl covered as opposed to walnut (wood) veneer.

Roy