Re Post: Inherited AR-4x speakers. How much do I rebuild?

[Roland]

Hi

As suggested I am reposting my original inquiry..Where I have already received encouraging feedback.

....

have inherited a pair of AR-4x that have been in the family for years and I am interested in rebuilding. I am a total speaker neophyte. They sound a bit flat, that is, not much sparkle or depth and when the volume is turned way up on my 110 Watt/channel receiver they do distort. Is it a given that I must change the tweeter and woofer?

Attaching photos. Both speakers woofer and tweeter seems to be in the same condition.

Thanks for any advice.

...

I am now including bits of the replies the original thread received.

...

member: ra.ra.

snip

...your speakers look totally original and possibly have never been opened or received any sort of maintenance in the past. This might very well explain the "flat" sound you describe, which might indicate that the capacitors require replacement or the tweeter controls (known as potentiometers, or "pots") require cleaning or replacement. You are basically not hearing the tweeters. As long as you can confirm that all drivers (both tweeters, both woofers) are operational, there is no need to replace them. Most likely, the bulk of the restoration work is inside the cabinet, and there are many, many threads here about the AR-4x.

/snip

Thanks for that ra.ra. Yes I would agree they have never been opened..

 

member: owlsplace

snip

... You have removed the grills successfully so you are of to a good start. This speaker model is iconic and yours appear to be in great shape.

/snip

Prying with two small screw drivers. Though I did indent just a bit the edges of the box in some places. At first start I did not realize the staples showing on top of the fabric went through the framing into the speaker wood.

member:stupidhead

snip

... as others have said unlikely you will need any new drivers. Plenty of guidance here to restore these to new condition. Intrigued by the pattern of what I assume to be mold on the cone of the woofer. What do the grilles look like?

/snip

The other cone also has the same "mold". I am inserting a photo of the panels and close up of the woofer

 

 

[nefertem]

Hi it depends on how much the mold is penetrated the paper cone and if replacement of the spider would change the original sound of the woofers 

[Roland]

Hi nefertem

Is it a given that the spider needs replacing, given the age of the speakers? 

[JKent]

Roland,

Welcome!

The advice you received from ra.ra. is spot on. Don't go tearing into the woofers or replacing drivers until you have done the most obvious repairs.

The AR-3a restoration guide will provide a lot of useful information. Your best bet is to get two 20uF film capacitors and two 15w 8 ohm L-pads. Replace the capacitors and L-pads and your speakers will probably sing.

I doubt the spots on the cones have any effect on the sound but you can probably wipe them carefully with a damp (not wet) cloth soaked in diluted bleach.

-Kent

[Roland]

Kent,

Thank you.

This very encouraging news. For me, this is sounding like an excellent DIY project. I grew up with these speakers in the house. I will study the guide, thank you classicspeakerpages, and start looking into getting the capacitors and L-pads.

If I am not able to clean up the grilles much what is the conventional wisdom? Stay with them because they are original or replace the fabric?

 

Thanks!

 

 

 

[JKent]

Roland,

There is a lot of information in the 3a restoration guide, including info on the grilles. The perfect replacement fabric is Wichelt 18-count linen in "lambswool" color, available online from 123 stitch. http://www.123stitch.com/item/Wichelt-18-Ct-Lambswool-Linen-Needlework-Fabric-27x36/59-135X

Ask a lot of questions here. There are no dumb questions--we've all been there. My 1st project was the restoration of my AR-4x speakers, purchased new in 1969. My 1st attempt at replacing the grille cloth involved some "NOS Vintage Speaker Cloth" purchased on ebay that was NOT authentic for these speakers. I then came here and John O'Hanlon, RoyC and others gave me a HUGE amount of help.

If you get L-pads (which I recommend although they are not "authentic") the wiring differs from the pots, so either search these pages or just ask and you'll get help. http://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248

The old wax block capacitors can be left in place--just cut the leads and splice in a new 20uF cap. http://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-436

Try to save the crumbly paper Kimpac behind the woofer but it can be replaced with thin cloth such as crinoline. The fiberglass should be saved (wearing gloves) and put in a plastic bag until ready to re-use. Or you can get small packages of Johns-Manville fiberglass insulation at Lowes. I think each bag is about 9 or 10 oz. and 2 bags per speaker is perfect. Advantage to the J-M is it has no formaldehyde. edit: I don't see the JM now but OC is good. Just not sure about the weight per bag http://www.lowes.com/pd/Owens-Corning-R6-7-5-6-sq-ft-Unfaced-Fiberglass-Roll-Insulation-16-in-W-x-4-ft-L/50370324

When you make your shopping list you will probably also want some speaker gasket tape from PE. Alternatively, you can get a block of dark gray "duct seal" in the electrical dept of Lowes, HD, etc. http://www.lowes.com/pd/Gardner-Bender-1-lb-Pug-Duct-Seal/4595233?cm_mmc=SCE_PLA-_-RoughPlumbingElectrical-_-ElectricalAccessories-_-4595233:Gardner_Bender&CAWELAID=&kpid=4595233&CAGPSPN=pla&store_code=1512&k_clickID=4f6358bb-25c3-41fe-9b9c-69527f83a661

You could also get all your parts--caps, L-pads, speaker gasket--from online vendor Vintage AR. His stuff comes with clear instructions and he is an honest seller so there is a convenience factor but he is in business to make a profit so you will pay more than if you order the parts from PE.

-Kent

[ra.ra]

Hi Roland,

You're getting lots of good advice here. One very good cap value is shown below - - - you can find less expensive options (non-polar electrolytics, or NPE's, for example) which will work just fine, but this cap is generally very well regarded as an excellent price/performance solution for your use in the 4x. Also, you can spend a whole lot more but that is not necessary. These 20uF poly caps are sorta large - - about 1" dia. by 2" long - - but there's plenty of room inside the cabinet. And the L-pad that JKent mentioned is also attached - - use these as your guides when you begin shopping.  

http://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-436 

http://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248

And before you go spending for brand new grille cloth, read up on threads like this one. The new cloth is really great but not inexpensive, so if you think you might be able to salvage those dingy grille cloths of yours (I do!!), try some gentle cleaning methods first. Instead of the 50-50 mix, I tend to prefer a solution with a little less bleach, maybe 40% or 33%.  

 

[JKent]

 LOL! Robert and I must have been typing at the same time but he added some good advice on the cloth. Hey--you have nothing to lose.

If the cleaning doesn't work and the 123 Stitch stuff seems too pricey you can try your local Michael's craft store (if you have one nearby). In the Needlepoint section they may have a roll of Irish Linen (actually imported from Poland) in "tea" color. It's 28 count, which is finer than the authentic 18 count, but a roll is about $9 and there are always 40% off coupons so for about 5 bucks you can get some very acceptable linen.

Here is  pair of AR-2ax's with the Irish Linen from Michael's

-Kent

 

[Roland]

Thank you for all the excellent advice and the picture Kent. I have a lot to digest since I am totally new to even understanding speaker technology. I will update the thread as I go and again thank you so much.

Roland

 

[lARrybody]

I restored a pair of 4x speakers in June. I also used the Michael's tea 28 ct linen. I found it to be a little too dark for my taste, so I soaked it in a mild solution of Clorox and dried it in the sun between two bath towels. I then ironed it with some spray starch. You can see in the photo a sample of the Irish linen before treatment. You can also see the original cloth saved in a zip lock bag.

 These had the wood frames, which I reinforced with glued on poster board gussets and painted black. I used the thin black grill cloth from parts express as a first layer and then the Michael's linen. I also installed a thin ribbon pull for easy removal. 

I used ideas from post by members der and jkent on rebuilding the crossovers. 8 ohm lpads with .25 ohm resisters and 20uf Dayton caps on nylon carriages. All wiring  replaced with 16GA stranded OFC. The original wax cap box can be pushed forward a bit to allow more room to install the cap. The original solder lug can be replace with a new on from the hardware store. The cloth surrounds were lightly coated with the Vintage AR sealant. One mistake I learned not to repeat. Even after two days the sealant remains very tacky.  Do not turn them over on newspaper to solder on new leads, they will stick.

Not only do these sound excellent for there size, they are easy to move around. Have two more pair in the wings awaiting attention, one 4x and a 4xa. They appear really nice without touching the cabinets. 

[Roland]

larrybody,

Excellent photos and description!

Thank you so much!

With my lack of technical understanding, I can say I am impressed with how you got the linen covering coloring right and that the pull tab is a common sense alternative to the original staples.

I am thinking I have the same type of grilles as yours. But I am not understanding  your description:

"  which I reinforced with glued on poster board gussets and painted black "

I do see that the wood is black but I am not understanding a poster board gusset. I am also thinking wouldn't something like that add to the depth of the grille and make it protrude from the speaker face?

Thanks!

[lARrybody]

The original wood frames were a little loose, only being held together with some old staples. I cut little pieces of L shaped and T shaped pieces of poster board and glued them with Aleene's Tacky Glue in the corners and middle joint. Then I painted the frame flat black. It really stiffened them up. No it did not add any significant thickness to the frames. Maybe you can see them in this photo.  

There are some really great people on this forum. I have learned a lot. Don't hesitate to as for any clarification. Good luck.

[briodo]

Great idea to use Michael's Tea Linen material.  For the price, it will suffice on a pair of AR2ax needing the second pair of screens due to pet issues.  While it may not be an exact match, your approach with bleaching solution gave great results and appear to match the original fabric...

I'm impressed with your results!

[JKent]

larrybody's 4x's look like perfect matches for my 2ax's--right down to the tabs on the grilles and the redwood lawn furniture speaker stands 

Mine were done several years ago, when the Irish Linen from Michael's still came from Ireland and was a better color match for the original cloth. The mild bleach solution seems like a good idea.

I would not use the double layer myself. Although KLH used a sheer black scrim behind the boucle grille cloth that was never done by AR and I would be concerned about losing a degree of acoustic transparency, especially with the more tightly woven 28 count cloth. Of course I haven't heard them so I may be way off. They certainly look great!

-Kent

[lARrybody]

I too was concerned about the loss of acoustic transparency. I just personally did not like looking at my 2ax,5 and 3a speakers and seeing the grill cutouts.  Yes I did take the idea from my KLH Model 6, 5 and 23 speakers. Even though I like to keep my  AR's as close as possible to original I made this exception.

The sheer black grill cloth from Parts Express has to be 100% acoustically transparent. I can actually read through it when back lit.

http://www.parts-express.com/parts-express-speaker-grill-cloth-black-yard-70-wide--260-335

The 28 count Michael's linen is slightly denser than the 18 count lambswool from 123stich, but not a great deal. Listening to the 4X's with the grill cloths on and off, I personally can  not tell a difference. With a little research (self education) I may be able to make measurements like Carl has posted. Anyway my conclusions are far less scientific. You can still see thru the grills.

 

 

[ra.ra]

Initially I had the same thought as Kent about the double layer grille cloth on larrybody's 4x's, but when I realized in his first post that you can actually see through both layers of fabric, I realized it's probably a moot point. Maybe with measurements there might be a slight difference in performance, but most probably not with my ears. And if it made that much noticeable difference, we'd all be normally listening with the lovely linen grilles off, looking at AR's gorgeous baffleboard layout.   Between the 4x's and Kent's 2ax's, it looks like you guys were working in tandem and trading shop secrets. Both projects are truly excellent. 

And yes, welcome aboard, Roland. In the future, you might try decreasing the size of your photo files - - - you don't need anything more than a 100 kB jpeg and this will make them more accessible for even the slowest low-powered computers to read.

 

[Roland]

 

19 hours ago, ra.ra said:

...Roland. In the future, you might try decreasing the size of your photo files - - - you don't need anything more than a 100 kB jpeg and this will make them more accessible for even the slowest low-powered computers to read.

 

 

I can to that. Thank's for the head's up ra.ra.

[Roland]

Hello,

I started on the take apart stage. 

First I have numbered the speakers and set up registration marks from the baffle board to the speaker with chalk. Most likely don't need it but I thought I was being clever. 

Following "Restoring AR-3a" pdf as a reference I took out the screws for the tweeter and woofer for one speaker. They came out easily and are the same size and did have "Mortite" (black stuff) on them. The screws have been saved in a bag which I will label.

Upon removing the woofer I ran into my first stopper. The leads are soldered.  I have a solder iron somewhere. Before I unsolder my concerns are:

• Dripping solder into the material below.
• Holding the woofer up while I work on un-soldering.
• Damaging the tweeter (still in place) and woofer while working. i.e. bump, puncture, drop, blowup

Any thoughts are appreciated.

Thanks!

[JKent]

Hi Roland

No problem.

Don't remove the tweeters. If you are nervous leaving them in you can tape a coffee can lid or some other kind of shield over them.

You don't "have to" solder. Cut the wires, leaving some room (like maybe mid-way). When you put it back together you can use small wire nuts. KLH did it all the time.

You WILL need to solder the l-pads and caps though.....

-Kent

[briodo]

Just a note to follow up on the Michaels Tea Linen, as I had to repair some grills for a family member with high strung puppy who tore through the original linen.  It turned out to be a close enough match for me.  I've included a picture with (left to right) original AR7 and AR3a linen, AR2ax with new Michaels covering, and the original linen from the AR2ax with holes from the puppy paws.  Fortunately the dog is no longer a puppy, so I'm hoping they should be safe from another incident.

[Roland]

Hello list

I finally got the capacitors and l-pads for the rebuild of my AR 4x speakers.

My woofers look good, as far as can tell.The spiders look good.

My understanding is the wires that came from round spool (resistor ?) to the woofer, which I cut to get the woofer out, will now go to the capacitors which will be mounted somewhere. The l-pads look more like a straight forward replacement if I get the wires right.

The Restoring the AR 3a has this solder shopping list (I have not soldered before) "Solder 0.032 or 0.065-in diameter rosin core / solder wick finely braided copper". All I could find at HomeDepot is in the photo. The solder is .040". Will this do?

 

 

Any pointers and/or references to the "Restoring the AR 3a" or links would greatly be appreciated. Thanks!

 

[ra.ra]

Hi Roland. The round spool is not a resistor, it is an inductor (or coil), and it is part of the woofer circuit. The red (positive) and blue (common) wires should be re-connected to the appropriate woofer terminals. The yellow and green wires, along with the capacitor and L-pad, are part of the tweeter circuit. Schematic diagram is attached, and you should be aware that the woofer and tweeter are not wired in-phase, meaning that the pos wire (red) of the woofer is connected to terminal 2 while the pos wire (yellow) of the tweeter is connected to terminal 1. You will need to snip the blue and green wires going to the original wax block capacitor, and connect them to your new cap.

edit: you also need to be aware that the new L-pad wiring is different from the original pot shown in the original schematic attached.

 

 

 

 

 

[JKent]

Hi Roland

The schematic Robert posted is good but you are a novice, as I once was, and maybe the schematic isn't that helpful. Notice the "jfo" in the bottom corner. That's John O'Hanlon, one of the authors of the AR-3a guide.

When I was working on my 1st speaker rebuild--also AR-4x's--John sent me this helpful photo with labels. The item marked "Zen" is the 20uF capacitor (I happened to use Zen brand caps). Don't worry about the "Gray" and "White" leads. Your caps have bare wire leads. Just be sure not to let any bare wire touch any other metal.

-Kent

[JKent]

And I apologize for not posting this earlier. You CAN do this job without soldering. Here is my 1st xo rebuild--the 4x--with crimp connectors used. 

Note that the pot shown in the schematic and the photo has terminals marked 1, B and 2. On your L-pads the markings are 3, 2, 1. So Pot terminal 1 = L-pad terminal 3. Pot B = L 2 and pot 2 = L 1.

Wish I had used color-coded wires to match the schematic but I think you can follow the wires. 

So looking at your crossover, and using L-PAD (not pot) lugs:

Terminal #1: One lead from the coil and a green wire from L-PAD lug #3 are attached to terminal 1.

Terminal #2: Red wire from + or red on the woofer and one end of the capacitor are attached to Terminal 2.

other connections:

L-PAD lug # 2 has Yellow tweeter wire attached. 

L-PAD lug #1 has the other capacitor wire and the Green tweeter wire attached.

 

The other coil lead should have been left attached to the rivet on the old capacitor bracket, as is the Blue woofer - wire.

-Kent

[Roland]

Excellent! The supplied photos help a lot. Regarding JKent's photo: "Clip old capacitor wires, solder new cap as shown". and his first rebuild. What happens to the old capacitor wire? Do they just sit there? It's not clear to me.

The second photo also shows me how I can get more slack in my wiring. Speaking of wiring what size wire would I use? Not that I am up to the challenge but would best practice say replace all the wires?

Also, do I need to hold down the capacitor with something? In one photo I see what appears to be a pink/red tie down holding down a capacitor. Regarding the capacitor, I see the Zend capacitor has its wiring coated should I wrap mine with electrical tape just to be safe?

Thanks for all your help.