robg222 Posted May 12, 2016 Report Share Posted May 12, 2016 I just ordered replacement woofers from Vintage-AR for my AR 4xs http://www.ebay.com/itm/161807792524?euid=285e0f4bfd3e4618a9b14d23cb9c52b4&bu=43837974202&cp=1&sojTags=bu=bu and Im going to use the phenolic ring tweeter 8 ohm from Parts Express. Im cleaning the original pots now and hope to use them. What capacitor should I use to replace the existing capacitor? I don't know much about electronics, is it just a matter of getting one with the same specs as the original, or is more consideration warranted? If the woofer were only for the AR 4x I would be less concerned, but it's a replacement for so many speakers, I imagine it must be treated differently in each application. Thanks Link to comment Share on other sites More sharing options...
stupidhead Posted May 12, 2016 Report Share Posted May 12, 2016 Hi Rob and welcome. I am curious why you are replacing all drivers, pics will always be helpful and appreciated on this forum. The caps do not effect the woofer, only the tweeter. A single 20 mfd is all that you need, and I believe you need a certain resistor if using the hivi tweeter. Geoff Link to comment Share on other sites More sharing options...
robg222 Posted May 12, 2016 Author Report Share Posted May 12, 2016 Well I thought that even the speaker that worked didn't sound very good, and the the other woofer sounded like it had marbles and wooden sticks in it at medium to higher volume. My first thought would have been to try to recone the woofer, but when I was unable to find any such kit, I just figured that it would have to be replaced, and better off with matched set. With regard to the tweeters, I thought that they would just be an improvement. Having said all that Im not averse to trying to using the original drivers, more like I don't think I know enough to bring em back to life that way, any help would be greatly appreciated. The cloth surrounds are supple and in beautiful shape. FWIW the tweeters are dated jan. 1967, the woofer that is broken is the one with the cockeyed cardboard dust cover that someone obviosly tinkered with. When I tap the cone with my fingers on the broken one, I can hear/feel metal touching from below. I found a recone kit from Queensland Speaker Repairs but they say its for a AR 4x-2748 but I don't know if my woofer is a 2748, or if it be compatible. Im also waiting to hear from them as the kit comes with a cloth surround or foam. Link to comment Share on other sites More sharing options...
ra.ra Posted May 12, 2016 Report Share Posted May 12, 2016 Hard to say, but the tweeters just might be fully functional after you re-hab the pots and replace the caps. The phenolic ring tweeter has generally been regarded as a very decent replacement (look for the thread on this created by Carl), but you should first try to confirm if the originals are working. Geoff is correct about the original cap value, and any of these links would be a fine choice (you'd need two 10's per cabinet). Personally, I prefer the lower voltage (and less expensive) choices, which also have physically smaller dimensions. (The comment about the hi-vi tweeter should be disregarded - - that replacement driver is suitable for other models with a larger diameter tweeter cut-out.) Your woofers appear to have those massive alnico magnets, and it would be nice to get them both working if you could. The top one looks good, but the bottom one has two oddities: the dust cap is obviously non-original, and there is a very unusual (yellow glue?) joint between cone and surround. Maybe you could post some close-up pics of the problem woofer to get further advice. https://www.madisoundspeakerstore.com/surplus-capacitors/10.0-mfd-polypropylene-cap-10mfdp/tyee/ https://www.madisoundspeakerstore.com/carli-capacitors/carli-mylar-20-mfd/ https://www.madisoundspeakerstore.com/solen-capacitors/solen-20-mfd-fast-cap-400v/ Link to comment Share on other sites More sharing options...
robg222 Posted May 12, 2016 Author Report Share Posted May 12, 2016 I also thought the yellow ring around the cone was glue, even in person. If you look closely however you can see that it its the tan/yellow cloth surround edge, just that the black gooey stuff does not go down that far as the cover the section of the cloth that is glued and does not flex during speaker use. So I went ahead and ordered the capacitors (thanks ra) and i will hear how the original tweeter sound. Where do even begin with that busted woofer? Link to comment Share on other sites More sharing options...
owlsplace Posted May 13, 2016 Report Share Posted May 13, 2016 4x woofers show up on the auction site quite often -- a pair went out the other day quite reasonably priced. According to RoyC AR was playing around with an aperiodic design when they made the 4 series. Those dust caps need to be vented to sound original. I'd be curious to see what is under that oversized dust cap. Roger Link to comment Share on other sites More sharing options...
JKent Posted May 13, 2016 Report Share Posted May 13, 2016 Welcome Rob Where to begin...... If your woofers have cloth surrounds they should not need to be re-foamed and certainly not re-coned. But that off-center oversized dust cap is something to think about. It may be that whoever worked on that just used the wrong dust cap and didn't know how to install it (OTOH that person should not have been working on speakers). Does that woofer have a cloth surround? From the photo it looks more like a foam-surround cone but I'm not sure. You could probably get someone (Roy maybe, or Bill LeGall) to repair that. The AlNiCo drivers are desirable. The phenolic ring tweeters are NOT an improvement. They're "OK" if the originals are shot but the originals are superior, The 2 things that will hurt the sound are the capacitors and the potentiometers, although neither of those affect the woofer. The caps should be replaced with any of the ones ra.ra. recommended and the pots "may" be able to be cleaned or you can replace them with L-pads (see the AR-3a restoration booklet for more on pots and L-pads). I would suggest you slow down, get help here and try to preserve and restore as much of the originals as possible. They are excellent speakers and well worth the effort. -Kent PS: Just re-read your post. Both woofers have cloth surrounds and it seems the bad one may have VC scraping. I don't know if Roy would be willing to tackle it. Bill LeGall at Millersound could fix it. If you decide to replace it be sure that the one you buy looks like your good woofer. As has been mentioned, AR used several different 8" woofers in the 4x and you do want a matching pair. Link to comment Share on other sites More sharing options...
RoyC Posted May 13, 2016 Report Share Posted May 13, 2016 Rob, Your speakers will no longer be AR-4x's with the new drivers. These are items of last resort that happen to fit the cabinet holes, and do not match the sound character of the original drivers. If all you have is one bad woofer, the best advice is to find a decent used 4x woofer to replace it. Any iteration of original 4x woofer would be a better choice than the new one. Roy Link to comment Share on other sites More sharing options...
robg222 Posted May 13, 2016 Author Report Share Posted May 13, 2016 OK...I'm going to keep these speakers intact and original. The tweeters work, the correct caps are on the way and I will try to fix the broken woofer while I look for a replacement. I will take that crooked cardboard dust cover off this weekend, and take a look see and report back. thanks you guys Link to comment Share on other sites More sharing options...
owlsplace Posted May 13, 2016 Report Share Posted May 13, 2016 14 hours ago, owlsplace said: 4x woofers show up on the auction site quite often -- a pair went out the other day quite reasonably priced. Actually, that auction didn't close yet: 371620249665. It is pretty common to see these color variations and even different cone types in AR-4x sets Roger Link to comment Share on other sites More sharing options...
robg222 Posted May 13, 2016 Author Report Share Posted May 13, 2016 Im watching them...thanks Link to comment Share on other sites More sharing options...
robg222 Posted May 13, 2016 Author Report Share Posted May 13, 2016 I attempted to remove that cardboard dust cover without damaging the cone, but its not going to come off so looks like I will have to buy another woofer. Inside however I can clearly see that a part of the cone has been torn out, probably when someone removed the original dust cover. How do you go about removing a dust cover without tearing the cone anyway? I tried to use a sheetrock knife blade in my fingers, but its impossible to get the right low angle. Also, would this tear be the cause of the woofer sounding bad? Link to comment Share on other sites More sharing options...
JKent Posted May 13, 2016 Report Share Posted May 13, 2016 Normally, when removing a dust cap you would slice around it, as you did, but with an X-Acto knife held at a low angle and cutting close to that flange. Then when installing a new DC you go a tad bigger to cover the the old remains. That hole may have a lot to do with the bad sound but also push down on the cone and see if there is any scraping in the voice coil. If there's no scraping you "could" try to repair the hole, if only for practice. You can glue a patch on there, using Aleene's Tacky Glue (best) or white Elmer's glue (will also work). For the patch, I like the reinforced paper lens wipes used for glasses or cameras but other paper will work. I think some guys use paper towel. Tear the piece instead of cutting to leave a ragged edge. You can then test the repair without a dust cap and if it's good you'll need one porous dust cap of whatever size you can fit on there. You'll probably have to cut the old cap down flush with the flange and glue the new dc down centered, with some of the off-center old flange showing. Before installing the new dc use a vacuum to suck out any dust or dirt that may have gotten lodged in the vc. Best bet is to get a used AR-4x woofer on ebay but you could get lucky with this one and practice some speaker-repair skills at the same time. Kent Link to comment Share on other sites More sharing options...
owlsplace Posted May 14, 2016 Report Share Posted May 14, 2016 7 hours ago, robg222 said: I attempted to remove that cardboard dust cover without damaging the cone, but its not going to come off so looks like I will have to buy another woofer. Inside however I can clearly see that a part of the cone has been torn out, probably when someone removed the original dust cover. How do you go about removing a dust cover without tearing the cone anyway? I tried to use a sheetrock knife blade in my fingers, but its impossible to get the right low angle. Also, would this tear be the cause of the woofer sounding bad? Okay, take the tape/cover off the sides of the magnet/pole piece and press down on the cone with all five fingers of one hand until you can get a good look at the voice coil. If the coil looks good you can take a shot at the cone repair. The vented 4x dust caps tend to go south when they are cut and normally there is no reason to since the cloth surrounds rarely fail. I've patched worse than this and they sounded great although a purist would cringe. Roger Link to comment Share on other sites More sharing options...
owlsplace Posted May 14, 2016 Report Share Posted May 14, 2016 On 5/12/2016 at 8:34 AM, robg222 said: Well I thought that even the speaker that worked didn't sound very good, and the the other woofer sounded like it had marbles and wooden sticks in it at medium to higher volume. My first thought would have been to try to recone the woofer, but when I was unable to find any such kit, I just figured that it would have to be replaced, and better off with matched set... Is it the angle of this photo or are those magnets larger than usual? Can you measure them with a ruler? Roger Link to comment Share on other sites More sharing options...
robg222 Posted May 14, 2016 Author Report Share Posted May 14, 2016 Owl, here you go, they measure 3.75 by just under 3. I think Ive seen these more than others while searching for them etc., it must just be the photos. I was able to nab those two woofers, hoping they're in good shape. Im not giving up on the broken one though, if only for the experience. Ive removed the yellow/tan cloth dust cover material and the magnet/pole looks OK, and seems to slide inside the voice coil without contact of any kind. I have watched a video about how to patch the cone with paper towel material and ordinary yellow glue, but that was a patch to a cone that had a cut, and all of the cone material was intact. My woofer is actually missing a peice, what about using something like thin paper plate or something like that? Link to comment Share on other sites More sharing options...
JKent Posted May 14, 2016 Report Share Posted May 14, 2016 Quote what about using something like thin paper plate or something like that? I think that's too thick/stiff. I like the lens cleaners--something thin but with reinforcing fibers. After you apply the patch (Aleene's Tacky Glue works best) you can thin the glue with water and paint it on the patch to make it stronger. You could also use a black marker to blacken the patch. Kent Link to comment Share on other sites More sharing options...
robg222 Posted May 15, 2016 Author Report Share Posted May 15, 2016 OK, now I get the idea. I don't have the lens cleaner tissue here at the house, I'll pick them up when I'm out. I really appreciate all your help. Link to comment Share on other sites More sharing options...
owlsplace Posted May 15, 2016 Report Share Posted May 15, 2016 10 hours ago, robg222 said: My woofer is actually missing a peice, what about using something like thin paper plate or something like that? I can send you a piece of AR-5 cone which is probably close enough if you want to try that. Just PM me with the size you need and a place to send it. Normally the VC attaches to the cone with epoxy so you may want to evaluate the cone to see how strong it is in that area. Someone may have tried to launch it into space with a high-powered transient or similar and stressed the cone/VC junction. Roger Link to comment Share on other sites More sharing options...
robg222 Posted May 16, 2016 Author Report Share Posted May 16, 2016 You are a step ahead of me. Looking closer to the damaged cone where it meets the VC, I can clearly see another small section that is just about broken and ready to fall out. I appreciate the offer, but I’m thinking its probably not worth the effort for this particular speaker, but thank you. Ill use the lens tissues and several coats of glue. It will probably take a number of test cuts to get a real good fit. Again thanks, awful kind of you. The wires inside the speaker look like 2 different gauges, what are they? They look like ordinary wires, nothing fancy. Im curious, sometimes forums like this ask for a donation towards the upkeep expenses of the forum. As a newbie to classicspeaker I’m not in a real good position to contribute based on my experience, but would be happy to throw in toward expenses if Im able to. If it is not clear, the dark area indicated by arrows left of box is the hole in the cone, while the lighter area inside the box is chunk of the cone which is creased/broken and will have to be reinforced as part of the hole patch repair. Link to comment Share on other sites More sharing options...
JKent Posted May 16, 2016 Report Share Posted May 16, 2016 Wires should be the same gauge: 18 ga tinned wire. Pretty ordinary. Marine wire works well. Very gentlemanly of you to ask about financial support. Years ago there was a "contribute" button but it didn't work! The site is owned by Mark Spencer, who pays for it himself out of a love for these old speakers. Once in a while you may see an ad for "Arsenal" pop up, and I believe that's his business but he really doesn't make the ads intrusive. Keep us posted on your progress! -Kent Link to comment Share on other sites More sharing options...
ra.ra Posted May 17, 2016 Report Share Posted May 17, 2016 Your photos are very good and helpful, and it looks like a multimeter can be spotted propping up one of the woofers, but I have not yet seen any DCR measurements reported on any of the drivers. Are they, in fact, all functioning "properly"? Let's establish that first before trying any delicate physical repairs. Kent's suggestion to try a patch repair using a strong, light, fibrous paper and a simple water-soluble craft glue is very good advice. He prefers a lens tissue while I prefer a coffee filter - - mostly because I always have them on hand but also because they accept all sorts of colorants (marker, paint, dye) very well to help conceal the repair, and their texture more closely replicates the paper cone. Roger's comment about the magnet size is astute, and exactly the point I was trying to make in my first post. I surmise that those may be the largest slug magnets found on 4x speakers, and because you have a matching pair, it is well worth trying to get them both up and running properly. (I have a pair of AR-6 woofers with huge alnico magnets, but mine measure a smidge smaller at 2-3/4" x 3-3/4".) Would be curious to know your 4x speaker serial numbers or a date stamp if you can find any on the backside of the drivers or inside the cabinet. Very interesting to see that unpainted ring on the inner diameter of the cloth surround - - - thanks for clearing that up. Link to comment Share on other sites More sharing options...
JKent Posted May 17, 2016 Report Share Posted May 17, 2016 Quote He prefers a lens tissue while I prefer a coffee filter - - mostly because I always have them on hand but also because they accept all sorts of colorants I had forgotten about that. Great suggestion! Link to comment Share on other sites More sharing options...
owlsplace Posted May 17, 2016 Report Share Posted May 17, 2016 Yes, outside of the flagship 3-series, I think the 4's pretty much defined AR during the late 60's and early 70's. The 4's seem to have given Timex watches a run for their money. Of course, Timex watches are long gone while the 4's are still ticking ... I think AR upgraded their internal wiring after the Norwood move to 16 gauge 105 C class wiring or maybe it was 18 gauge. To me the garage-build quality of the Classic-era was part of their charm. Roger Link to comment Share on other sites More sharing options...
robg222 Posted May 22, 2016 Author Report Share Posted May 22, 2016 OK, I now have the new capacitors, and the wire was just delivered. In addition the pair of woofers I was able to get on the auction site have also been delivered. They were packed with the surrounds flat against cardboard which flattened them some, but not too bad. Note that the magnets on this pair are smaller, measuring about 2.75” both ways, while the original pair are 3.75 x 3.0. There are no dates on the original woofers, only 8W-5020 stamped on back of the cone. The tweeters however are both dated JAN 28 1967. The auction site woofer cones also have some numbers stamped on them, but I can not read them. The DCR on the original pair is 4.8, the auction site pair are 6.0 and 6.2. My plan is to use the auction site pair, what does it mean that a 0.2 DCR variation exists between these two woofers? Im about ready to start putting them back together. One pair came with a white foamy gasket material, I also have electrical putty that i used on a pair of smells that i re-faomed, or i have the sealer that i bought from vintage-AR on eBay, which should i use? Link to comment Share on other sites More sharing options...
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