AR6 - how to begin project?

[crumpets]

Hi All,

I have inherited a pair of AR6's that are in very nice condition, at least cosmetically. I am thinking of making them my first resto project.

From what I can tell they are the Ver. B. The tweeters are working. Both woofers have been replaced with an Arista brand. They have that cap and resistor on them that I think some refer to as a "zobel". Basically, they sound very average.

I have tried a couple of other AR woofer in them, some 1210037-2A woofers that came in a pair of beaten up AR18's, and 200001-1 woofers from a pair of AR94's. I have not tried installing the zobel on either of those woofers. Both sound better than the Arista, but still well below par. At the moment I have the 200001-1 woofers in the old AR18's(last pic) and they are now sounding great. Anyway, back to the AR6's.

My first question is what is the best driver for this version of the AR6? Would the 200001-1 woofers I have be suitable, or should I be looking for 1200001-4 or something else? Also, is it wise to connect the zobel to the replacement driver?

Secondly, given the tweeters seem to be working ok, what else should I try and replace? I must admit to being a complete novice. The extent of my speaker repairs to date is refoaming some 1210037-2A woofers, which went fine. I know this is a much bigger undertaking, but I'm keen to give it a go. Where to start?

 

[Giorgio AR]

You can purchase this as a valid substitute for the 200001-1 woofer

 

https://www.ebay.it/itm/223026926990

 

[JKent]

Welcome Crumpets!

I have no experience with the AR-6 but did find the threads below that may be a starting point. Judging by the speckled finish on the back, yours are European versions. Scroll down through the attached post and you will find 2 schematics. The 2nd one is for your speaker. Looks like the resistor and cap on the woofer ARE correct but wait for member ra.ra. to chime in here because he knows quite a lot about those.

Based on what I read in the linked post, your donor 200001-1 woofers should be the perfect match and you SHOULD install a 10 ohm resistor and 24uF capacitor in parallel with the AR woofer (I don't think it's a Zobel. From what I read a "Zobel network is a series resistor-capacitor network that is connected in parallel with a loudspeaker driver". The AR-6 has the resistor and capacitor both in parallel with the driver).

The blue compulytic (I assume) cap in the crossover is probably still good. Don't know about the cap on the woofer. What is the brand and value? Do you have a way to test it? You may not need to replace anything at all after the woofer swap, unless the grilles are shot. Are you in Europe or on this side of the pond?

-Kent

 

Here;\'s another good thread:

 

[crumpets]

Thanks for the welcome Kent, and that great information.  I am from Australia, btw. I had a close look at the second thread you posted. The cap on the woofer is identical to the one from that thread, INDUSTRIAL Royalite long life 24 uF 50V NP. In fact, my AR6 version appears very similar, except that my tweeters are rear wired and the others front wired.

So, from what I understand, the crossovers may be fine to leave as original, and I should just get 2 new 24 uF caps for the woofers, join the cap/res to the 200001-1's and see if that does the job. If not, then look at changing out the blue caps on the crossover board. Does that seem like the way to go?

Having tried the 200001-1 woofers by themselves(without the cap/res attachment) without much success, I am hoping the addition of the cap/res will make a considerable difference and bring them back to life. Otherwise, maybe there is something else to consider. I have included front and rear pics of the rear wired tweeter. The tweeters don't have any readable part numbers, so maybe somebody could tell me whether they look original to this version of AR6.

I have also attached a pic of the other set of woofers I have available, and suggested as suitable replacements above (1210037-2A). I would prefer to use these as I have the 200001-1's in AR18's. Actually, I tried the 1210037-2A's in the 18's and they didn't sound as good. Hmmmmm!

I've never purchased caps before. Does this seem like a suitable replacement for the 24uF caps for the woofers, or are there better alternatives?

https://solen.ca/products/capacitors/dayton-metallized-polypropylene-capacitors/dmpc-25/

 

[JKent]

Hi Crumpets

Those tweeters look right to me but I'm waiting for someone with first-hand experience with the AR-6 to chime in.

Before buying caps you might try using the ones you have with the correct woofers. But to answer the question, yes--those Dayton 25uF caps would be fine. You said you've never bought caps before so a few things to consider:

• You can go +/- 5% to 10% in value (microfarad, mfd, uF) so the 25uF is a good sub for 24uF
• You should go higher in voltage rating. The originals are 50vdc. Anything above that is fine (100, 250, 400, whatever)
• Film caps, like the Dayton you linked or Solen, etc. are more expensive but last virtually forever.
• You can also use NON-POLAR electrolytic caps, sometimes called NPEs. They are smaller, much cheaper but have a finite lifespan (maybe 20-40 years). The original caps in your speakers are NPEs
• The blue Compulytic caps are excellent and last longer than most electrolytics. OTOH, they're getting a bit long in the tooth and IF you are buying caps I'd replace those. 10uF film caps are cheap: https://solen.ca/products/capacitors/polyester-capacitors/pemt160j106/   or   https://solen.ca/products/capacitors/fast-capacitors-250v-pa-series-metallized-polypropylene/solen-pa1000/
• Capacitors can be wired in parallel to make the desired value. So you could, for example, use two 12uF NPEs on each woofer, for about 2 $CAD per speaker: https://solen.ca/products/capacitors/non-polarized-electrolytic-capacitors/b05a100k126/

A couple of very basics things (forgive me if you already know this stuff):

• Make sure the cabinets are virtually air-tight. When a speaker is all sealed up you can push in on the woofer cone, using 3 fingers around the perimeter of the dust cap, and it should return slowly. If it pops right back out there is a leak and bass response will suffer. New gaskets for the woofers AND the tweeters (if they were removed) usually fixes this.
• Make sure you have the correct amount of fiberglass stuffing. I don't know how much the 6's take but maybe another member can help here.
• Check the polarity on your woofers. Very rarely (but sometimes) they are marked wrong. Take a 1.5v battery (0r 9v) and connect the + side of the battery to the + woofer terminal, - to -. The cone should move outward. 

That's all I can think of for now.

-Kent

[RoyC]

8 hours ago, crumpets said:

Having tried the 200001-1 woofers by themselves(without the cap/res attachment) without much success, I am hoping the addition of the cap/res will make a considerable difference and bring them back to life. Otherwise, maybe there is something else to consider. I have included front and rear pics of the rear wired tweeter. The tweeters don't have any readable part numbers, so maybe somebody could tell me whether they look original to this version of AR6.

Kent has provided good advice.

Your tweeters are original to the AR-6. The 1210037-2a is a later woofer, not original to the 6, and not likely to work very well. The 20001-1 woofer shown in your photo is not original to the 6 either, though it is somewhat earlier (the date stamp indicates 1980). It should be a better match. A mid 70's AR 8 inch woofer would likely work best of all. It is unlikely the caps are the reason for your disappointment in the sound, though they are easy enough to replace.

There are so many versions of the AR-6, I often wonder whether AR was ever satisfied with this model. The first version had a more sophisticated crossover than subsequent versions.

Roy

[ra.ra]

Hey crumpets, I've seen as least two pairs of this version (B) of AR-6, so I'll just show you what I've run into from my examples. I've looked at this issue a long time and still get confused about the various iterations of the AR-6, so let us know if this doesn't make sense or you have further questions.

Oops, I see that RoyC has just responded, and I've got a few other thoughts.

Your pair looks pretty good and mostly original - - -  they appear to have the narrow slimline front molding and spatter paint backsides typical of the Euro models, but it looks like they've lost their serial numbers, yes? And I think that 001 woofer is the original driver to the AR-18 and so it should probably stay there - - particularly if they are sounding so good - - what a sweet small speaker that model is! You mentioned that the 001 woofers came from a pair of AR-94's, which has me curious about the other pair of 8-inch drivers from those cabinets? Also, can we see that 037 woofer from the front side?

I agree with Roy that the tweeter is original. This series of tweeters had either a 2-1/8" or 2-3/8" diameter magnet. Two pics attached show a partial evolution of the 1-1/4" tweeter. From L to R:

• front-wired, small magnet, DCR 4.9 ohms, date 1971, from early AR-6
• rear-wired, small magnet, straight lead wires, DCR 4.8 ohms, date 1982, p/n 200005 (this one looks like yours)
• rear-wired, large magnet, curved lead wires, DCR 5.3 ohms, date 1984, p/n 200038

On one pair, I left the original 10uF blue Sprague caps (tweeter) because they sounded good and measured well. In the second pair, I replaced the original cap with a generic film cap only because the two cabinets had mis-matched caps and the smaller cap was no longer measuring well.  

[JKent]

crumpets:

Roy and ra.ra are the two most knowledgeable guys regarding the 6 (IMHO) so you have good info here. It's frustrating that there were so many AR 8" woofers and the 200001-1 is not a perfect replacement for the 200001-4. 

Maybe see how the 001-1 sounds with all the xo components installed and keep an eye out for "A mid 70's AR 8 inch woofer" as Roy suggested. Don't know how available those are in Oz but you could get lucky.

-Kent

[ra.ra]

About the woofers, I want to offer two thoughts that are a little different from Kent and Roy, and also to show pics of the specific woofers I found in both pairs of AR-6's, version B. First pic shows backside of woofer with square magnet, sticker with unfamiliar parts number, 1974 date, and piggyback 24uF cap and 10 ohm resistor. Second pic shows close-up front view which features 1/8" thick masonite ring at spider and similar thickness cardboard ring at outer basket perimeter. This is shown just for information.  

Kent's advice is all good except that I would recommend you might not want a film cap for the woofer circuit. This is a parallel and not a series capacitor and therefore seen by many as not as critical. There is the higher cost issue for film, too, but mostly there is the physical size issue - - see generic comparison of film and electrolytic caps of roughly the same uF values. A film cap will function just fine - - no question - - but hanging a huge cap off the back of the woofer will be awkward. I'd say to select film only if you locate it remotely inside the cabinet. I've used only dimensionally smaller electrolytics here (sorry, no pics), and be forewarned that you'll probably have great difficulty locating a cap in 24uF value - - - 25 would suffice or as Kent has suggested, pair up two 12's or similar. 

Roy's advice is also very good but I'm going to suggest that the 037 woofer just might be a suitable component here. The only reason I say this is because I have a pair of AR-7's (which used 001 woofer) that had factory replacement woofers like yours (see pic), and these particular Tonegen drivers were stamped with 037 designation and covered with 001 paper labels. This leads me to believe that at some point these two woofer numbers were deemed to be interchangeable as replacement parts. Although I prefer the look of the original AR-7 woofers, these 037 replacements sound terrific. I also have 037 woofers in a pair of AR-18s and they are excellent as well, but in both of these cases, the 037 woofers are used with no coil, no cap, and no resistor.   

I'd like to see you to get these up and working well without having to go on an international shopping spree for new drivers. Since the 037 installation did not sound good without the piggyback components, try it out with the R+C on the woofer backside.

[ra.ra]

2 hours ago, RoyC said:

There are so many versions of the AR-6....

 

1 hour ago, JKent said:

It's frustrating that there were so many AR 8" woofers.....

Ain't that the truth - - you guys are right - - it's confusing trying to sort this out 35 or 45 years later.

[Giorgio AR]

Here is my AR6 woofer with the masonite ring under the spider, together with the photo of the AR6 speaker

[crumpets]

Kent, that info about the caps is making more sense, thanks. And, I see what ra.ra means with fitting the larger caps on the woofers being a tight squeeze.

This is what I’ve come up with...
https://www.wagneronline.com.au/non-polarised-axial-electrolytic/capacitors/electronic-components/22ry100-589/57/pd/ . Them, with a 2.2uF to bring it up to 24.2uF, for the woofers.

And these to replace the 10uF compulytics.
https://www.wagneronline.com.au/metalised-polypropylene-mpt/capacitors/electronic-components/mpt-10-0-58263/971913/pd/

Kent, thanks for those tips re stuffing, sealing and polarity. I'll do that with the battery and hopefully someone can help with the stuffing mass. There is a lot of stuffing in these AR6's. Chock a block, actually. Also, I had only recently been looking into sealing cabinets effectively. After plenty of reading I decided to try the rubberised cork for the gaskets on the 18’s because it is so user friendly. After reading your post I went over and tried the rebound test on them. I’m not so sure they are slow to return. I did notice a slight noise on one woofer though and, wouldn’t you know, it turned out to be some air escaping through one of the unused screw holes(8 holes, only 4 screws). So thanks for the reminder. Although I can’t really say if they are passing the rebound test, the woofers are certainly moving in/out more than previously during play, and I do keep getting a surprise at how good they sound now.

I have a feeling I have not tested the 1210037-2a woofers since changing the gasket, so that might account for me favouring the 200001-1’s. RoyC, would you happen to know the part numbers of any of the mid-70’s woofers offhand, apart from the 200001-4?

ra.ra, I have included a photo of the front of the 1210037-2a woofer. Also a photo of the remaining original woofer in the 94 cabinet, the 200027. I believe I have seen an AR94 build sheet on here which led me to believe all the 94 drivers were original. The 94’s definitely sounded fine, just not in the same league as the 18’s for my ears, or what I expect these AR6’s should sound like with some tlc. I can live with the 94’s being sidelined for now.

I think I’ll go with your suggestion ra.ra. Leave the 200001-1’s in the 18’s and modify the 37-2A’s when I get the new caps. If someone could let me know whether those parts in the links are suitable, I’ll go ahead and order them. I spent quite a bit of time scouring the web to find them here in Aus, so hopefully they’re right.

Thanks again you guys for taking the time with your replies. I’ll have another read of your posts when I get a chance to see if I missed anything. Your support means a lot, and I feel like I can get this done now. It seems like this project is a good place to start. I won’t mention the state of my AR5’s….Anyway, one thing at a time.

[crumpets]

Very different hey, Giorgio. Much more like the AR5's/2ax's I've seen. Any idea which incarnation seems to be preferred?

[ra.ra]

Looks to me like Giorgio's AR-6's are the early version (A), having that woofer with ribbed cone and huge alnico slug magnet. I would suspect these would also have the dual coil crossover and potentiometer control.

crumpets, you seem to be on the right track here, as long as you accept that the use of the 037 woofer is still in the "experiment" stage. Those cap choices look absolutely fine to me, and essentially identical to what many of us would find and possibly use if purchased in the USA. That Dayton poly cap is a favorite for many restorers, and a very good value. The 100V NPE is pretty much what I was suggesting, and along with the 2.2uF cap (and re-used resistor), it all should fit well enough against the woofer magnet and basket along with a little hot glue. Just to re-iterate my earlier point, take note of dimensional differences: 10uF poly cap (250V) measures 22 x 46 mm; while the 22uF NPE cap (100V) measures 10 x 24. This results in a factor of 9x for comparative cylindrical volumes. For situations such as this where physical size is critical, it often makes good sense to use a smaller NPE cap, particularly if its use in the circuit probably does not benefit from a more costly cap.  

Re: stuffing, all AR-6 cabinets I've seen have been tightly stuffed. However, in the USA I've only encountered fiberglass fill, and it looks like yours may contain the multi-color fiber fill found in many Euro models, similar to what can be seen in your AR-94's. I have never weighed the fill - - I simply make certain to keep each speaker's removed pile segregated and then later returned to original cabinet. 

About your 94's - - - all of those drivers look excellent. The tweeter (038) is the same as one I showed in earlier post; and you are correct that the 027 drivers are original. These are noted as lower mid-range drivers - - not knowing more about their specs, but I doubt these could ever work well as stand-alone woofers. And yes, the 001 woofer is original to the 94, too.    

Your 037 woofers look like anticipated, with that heavy textured cone and spongy flexible dust cap. Re: rubberized cork, I like that material a lot but have never used it for speaker gaskets - - - as long as it is noticeably compressible, it should work fine. 1.6mm thickness is very similar to the 1/16th inch craft foam I've often used for speaker gaskets. Keep us posted.

[crumpets]

Thanks, ra.ra. That's good news re. cap selection. I will go ahead and order them. I'll try the 037 first. I may be able to get my hands on some other 200001-1's if needed.

Yes, the stuffing in the AR6's is the multi coloured fill. I have it in separate bags.

Had a thought last night that it may be worth my while ordering what I need for the AR5's that will be fixed up next(assuming the 6's go ok). I will start another thread on them and see if anyone can suggest what I might need. Would you mind casting your eye over it when you get a chance.

 

[ra.ra]

1 hour ago, crumpets said:

....it may be worth my while ordering what I need for the AR5's....

This is always a good idea to combine parts orders when you can, and there are plenty of members here with plenty of experience and advice on the AR-5's, so it's never too soon to start a new thread just to show (pics!) and explain what you are working with. As you probably already know, AR-5's typically require primary attention in three areas: foam surround replacement, capacitor replacement, and potentiometer maintenance or replacement. That Wagner source looks like a very decent AUS supplier - - always good to avoid international shipping when you can.

(Parenthetical note: If this current plan of attack for your AR-6's ultimately does not deliver satisfying results, I've got one more harebrained idea - - even though I've got no hands-on experience here. My thought is that it just might be worth, as a last resort, trying to implement the simpler AR-6 version (C) crossover - - using the 037 woofer - - but keeping your three-position switch in place. You'd have to eliminate the piggyback components on the woofer, and abandon the coil as well, and maybe even try a 6uF tweeter cap. This configuration was presented to this forum my member KlausDK from Denmark, and the general simplicity of this circuit seems to have been adopted with great success in subsequent AR two-way models with 8-inch woofers.) 

[crumpets]

Hi all,

A quick update on the AR6 recap....Had a go at it last night.

First, I removed the old resistors from the non-ar woofers and soldered them onto the 037 drivers with the 2 x 12uF caps. Being my first attempt at soldering, it was a bit tricky. I was worried that some hot solder might drop onto the cone, so I was a bit anxious. Anyway, it seemed to work in the end. I didn't bother using hot glue for this because all sat nice and secure with plenty of room (thanks everyone for the advice re. using the NPE caps for this).

Replacing the blue caps on the crossover board was a fair bit easier. I used the connectors for this and will probably go this way in future, wherever possible. The only issue was that the black wire going to the cap was very short. I managed to strip it back enough to enable the connection, so all good. Used a hot glue gun for the first time to secure the 10uF Dayton caps.

All back together now. Was it worth it?

Sure was ! The 037 woofers seem to be a very nice match, now that they have the r/c added. I was nearly going to take the 200001's out of my 18's, but in the end I went with ra.ra's suggestion of giving the 037's a try. The bass is very pleasing. Much better than without the r/c components. In fact, much better than I had hoped.

The new Dayton caps have made a huge difference. The sparkle is definitely back. I don't feel like I am missing any of the ambience anymore. Vocals sound sensational.

Thanks everyone for your help with these. I'm so glad to have my first venture into speaker restoration under my belt. Now I can tackle the ar5's with a bit of confidence.

[ra.ra]

Glad to hear things have worked out well. Even though the original blue Compulytic caps are sometimes still performing well, it sounds like your new Dayton caps have made a noticeable difference, and it's great to hear these 1-1/4" tweeters when they provide full output. 

With the woofer experiment, you were treading into uncharted territory, so I'm pleased to hear this arrangement has proved satisfying. There is still some confusion regarding similarities and differences among the various AR 8-inch woofers, so trying the 037 woofer in lieu of the original was a bit of a crapshoot. Added to that, the R+C components riding piggyback on the woofer are an unusual configuration, so this experiment was largely a mix-n-match attempt to assemble some high performance speakers with available parts at hand. A properly working AR-6 should produce surprisingly deep bass from an 8-inch woofer, so continue to audition your new speakers with some bass-heavy source material to confirm this.  

I just noticed the "Fleetwood LTD" stamps on your x-o panels, and I think this also confirms the speakers were originally assembled at the facility in England. Great project....congrats. 

 

[crumpets]

Thanks, ra.ra. I  will do some comparisons between the 18's with the 001 woofers and these ar6's when I get a chance. My initial thoughts were the 6's bass was maybe a little deeper, whereas the 18's have that fantastic precision. I haven't looked into the figures at all so I have no idea what each should be capable of. I do remember reading a thread about what models people loved the most and someone said they wouldn't be surprised if the 6's or 7's got a mention. I may still have access to another pair of 200001-1 woofers, so will probably be tempted to give them a go now I am a little more confident. It might be a while though. The ar5 project has really turned out to be the big winner for now.

At some stage I should start a new thread to get some thoughts on recapping my 9LSi's. From what I've read the configuration of the crossover board sounds fairly daunting. Are they bit too tough for a novice?

[ra.ra]

On 3/8/2019 at 6:22 AM, crumpets said:

..... recapping my 9LSi's.... Are they bit too tough for a novice?.... now I am a little more confident.

You're no longer a complete novice any longer, and I think you've answered your own question here . The larger speaker will indeed be more of a challenge but if you go slowly and work carefully and ask questions, you can tackle this project, too. I think this model has been well documented in these pages, and I believe it may have some unique assembly issues that you may want to research beforehand. 

Is it possible to post a pic of the completed AR-6's showing the 037 woofers in place?

[crumpets]

ra.ra, my apologies for taking so long to reply.

Here is a pic of the completed AR6 with the 037 woofer. I have been listening to the recapped 5's pretty much exclusively, but have the AR6's playing at the moment. I think new seals are required to get the best out of those 037's, but they are sounding very nice.