stupidhead Posted February 13, 2016 Report Share Posted February 13, 2016 So I recently saw an auction site listing for these and they just spoke to me. Turns out the seller is from our home town and local sale is always good, for both parties. Buyer can see touch feel and neither party has to worry about shipping hassles/issues. We went back and forth a few times before coming to terms on price, but in the end we met and made the transaction. Not that I need another set of speakers but I couldn't resist. I have really been enjoying my first set of 5's and I have to think stacking two sets would be awesome. So without further commentary, here they are in the condition I received them. The typical old set of nice speakers that have been out of service for some time and showing signs of age. One of the grilles was off, and no frame damage, the other was still in place and the inner face of cabinet showed numerous mild prying evidence of someone trying to open the vault, unsuccessfully. After trying for a while myself, i bailed on trying to get this off intact and sliced the cloth around the perimeter and was able to get this stubborn frame off. A few observations at this point. Notice the bottom inner edge is loaded with a heavy accumulation of generic dust, I believe. Also, the glue applier was heavy handed and some of the glue was visible on the border of the cloth edge, not just the stapled edge. Was this ooze or was there a thin bead applied there also? My sense is that it was ooze from an excessive bead on the face, but it sort of seems deliberate. Either way I will clean these surfaces up before all is said and done. The surround glue was rubbery and pliable to the touch and in fact peeled away easily and completely from the cone. I happen to have an extra set of BA filled filet surrounds on hand, so full speed ahead. Here is a pic of the other set of drivers, all seems right and I am encouraged thinking I have a nice un-molested set of 5's, vintage still unknown. The serials on these are 29837 and 29844, pretty close. Cambridge full size labels. My other set has the smaller Norwood labels and were 37918 and 37919. I don't have a clue how the factory laid in the mortite as far as procedure, but you can see in the above pic that it seemed as the application was a little hap hazard and certainly inconsistent when looking at the squished out mortite from drawing the driver into place with the four screws. I said to myself this seemed a little sloppy, and began to wonder if someone (not factory) had done this. Then I remove the first woofer and more suggestion of not assembly line work! This pic is what was revealed. There was a batch of insulation between the Kimpac (thanx Kent) and the driver? Huh? and also more evidence of the sloppy mortite application. My impressions of QC for AR has always been of high standards for these vintage specimens, however I am getting a different impression with this set. Was there maybe a personnel issue in this period? It is at least curious to me. Here are the other drivers for dating purposes.. and these are adding to my curiosity about this set. Between the three drivers, there is a three plus month spread in dates! Not that I expect them to match necessarily, but three plus months seems like quite a spread. Then there is this! which clearly shows evidence that there had been a screen on this basket, but for some reason it is gone. What the heck? Geoff Link to comment Share on other sites More sharing options...
ra.ra Posted February 13, 2016 Report Share Posted February 13, 2016 Congrats, Geoff, that's a real nice-looking pair of AR-5's, and without seeing the backs or the insides, it sure looks all original to me. Too bad you had to sacrifice one of the grille cloths - - looks like they had no tears or splits in them, even if some of the usual discoloration due to age is present. It would have been nice to clean 'em up and re-use them. I hope the mids and tweets are all working at least. The dates on the drivers don't surprise me at all, but since the latest date shown is Feb '73, I suppose you can simply identify them as being from that period. More curious is the double date stamp on the mid. Remember, the model 5 employed the same tweeter as the 2ax but was not a huge seller - - assembly of the 5 probably occurred far less frequently than the 2ax and although I don't know what the actual physical or performance differences are, the 5 and 2ax woofers had different part numbers according to the 1979 parts list in the Library. Just guessing here, but yours may have been assembled shortly after a fresh batch of 5 woofers passed inspection. Yeah, the missing woofer screen is maybe a little odd and so is the afterthought blob of fiberglass, but I've read on this forum about far more odd AR specimens, and besides, both of your "flaws" can be easily corrected during your re-build. Not sure if this is the point you're getting at, but contrary to your statement about QC, I've often been underwhelmed by the build quality of these early models. Yes, I love the T-nut driver attachment detail and the general walnut+linen aesthetic and several other things about this product line, of course. However, the quality of the plywood and MDF used in cabinet assembly seemed to vary substantially; the black rope caulk was inconsistently applied (with no trimming of the over-squish); and the crossover components sometimes seemed slapped together willy-nilly with regard to component placement, stapling template, or glue patterns. And then there is the black electric tape on the baffle - - - not a terribly sophisticated design feature. Nonetheless, there is a certain charm to the assembly details I just complained about, and in my own projects, I like to make some simple improvements in some of these areas while trying to not stray too far from the spirit of the original product. I still hope to have a pair of 5's someday, and your 'new' ones look like another excellent pair for a full restoration. Link to comment Share on other sites More sharing options...
RoyC Posted February 13, 2016 Report Share Posted February 13, 2016 Hi Geoff, Your specimens are very consistent with all the 5's I've seen, including the fiberglass on top of the Kimpac, though the missing screen section on the woofer is unusual. Perhaps this speaker was repaired at the factory early on. The woofer's crossover inductor and one of the midrange inductors were changed in the 5 along the way, as was the woofer itself. The earlier woofer had a larger magnet than the much more common AR-2ax woofer. I'm interested to know the numbers on the coils in this pair. Based on the serial numbers I suspect it will have the later #10 and #11 coils. Roy Link to comment Share on other sites More sharing options...
owlsplace Posted February 13, 2016 Report Share Posted February 13, 2016 Congrads, Jeff on your number two set of AR-5's. I passed on a number four set recently, then changed my mind only to find out I was too late. I'm guessing these are a bi-product of the Norwood shuffle. They look great to me and I'm guessing again that they still have wax caps. Roger Link to comment Share on other sites More sharing options...
stupidhead Posted February 14, 2016 Author Report Share Posted February 14, 2016 15 hours ago, ra.ra said: Quote Congrats, Geoff, that's a real nice-looking pair of AR-5's, and without seeing the backs or the insides, it sure looks all original to me. Too bad you had to sacrifice one of the grille cloths - - looks like they had no tears or splits in them, even if some of the usual discoloration due to age is present. It would have been nice to clean 'em up and re-use them. I hope the mids and tweets are all working at least. Thanx Robert. Trust me I tried to get that off but just couldn't do it and someone before me had already dinged up the inner cab edge from previous jail break attempts. The sacrificial cloth will still be used, after a thorough cleaning from Diane. I have a set of 4x they will be used on and I will likely use some 1-2-3 linen for the 5's. Diane enjoys reviving this old linen and I am often shocked at the results she gets. As for the drivers, I have only dug into the first one so far, but all drivers are functional, have yet to extract the pots, but they are quite crusty feeling and are the non-plastic stemmed style. Black pointers intact! Quote Link to comment Share on other sites More sharing options...
stupidhead Posted February 14, 2016 Author Report Share Posted February 14, 2016 15 hours ago, ra.ra said: Quote The dates on the drivers don't surprise me at all, but since the latest date shown is Feb '73, I suppose you can simply identify them as being from that period. More curious is the double date stamp on the mid. Remember, the model 5 employed the same tweeter as the 2ax but was not a huge seller - - assembly of the 5 probably occurred far less frequently than the 2ax and although I don't know what the actual physical or performance differences are, the 5 and 2ax woofers had different part numbers according to the 1979 parts list in the Library. Just guessing here, but yours may have been assembled shortly after a fresh batch of 5 woofers passed inspection. Yeah, I was figuring first quarter 1973, and I will be curious to see the date stamps on second unit's drivers. I appreciate your other insights as well, thanx for those. Quote Yeah, the missing woofer screen is maybe a little odd and so is the afterthought blob of fiberglass, but I've read on this forum about far more odd AR specimens, and besides, both of your "flaws" can be easily corrected during your re-build. Not sure if this is the point you're getting at, but contrary to your statement about QC, I've often been underwhelmed by the build quality of these early models. Yes, I love the T-nut driver attachment detail and the general walnut+linen aesthetic and several other things about this product line, of course. However, the quality of the plywood and MDF used in cabinet assembly seemed to vary substantially; the black rope caulk was inconsistently applied (with no trimming of the over-squish); and the crossover components sometimes seemed slapped together willy-nilly with regard to component placement, stapling template, or glue patterns. And then there is the black electric tape on the baffle - - - not a terribly sophisticated design feature. My QC observation is likely influenced by my love for the resulting speakers, you are spot on that there was not a tremendous amount of sophistication to the actual build. At the end of the day I feel there were some craftsman in that factory, not just assembly line workers. Quote Nonetheless, there is a certain charm to the assembly details I just complained about, and in my own projects, I like to make some simple improvements in some of these areas while trying to not stray too far from the spirit of the original product. I still hope to have a pair of 5's someday, and your 'new' ones look like another excellent pair for a full restoration. your thoughts here very much mimic mine. You will find a set eventually, and of course I will keep my eyes open for you. Link to comment Share on other sites More sharing options...
stupidhead Posted February 14, 2016 Author Report Share Posted February 14, 2016 13 hours ago, RoyC said: Hi Geoff, Your specimens are very consistent with all the 5's I've seen, including the fiberglass on top of the Kimpac, though the missing screen section on the woofer is unusual. Perhaps this speaker was repaired at the factory early on. The woofer's crossover inductor and one of the midrange inductors were changed in the 5 along the way, as was the woofer itself. The earlier woofer had a larger magnet than the much more common AR-2ax woofer. I'm interested to know the numbers on the coils in this pair. Based on the serial numbers I suspect it will have the later #10 and #11 coils. Roy Hi Roy, Thanx for chiming in. So the handful of insulation under woofer was done on other 5's too, interesting. I often wonder about what motivates some of these anomalies. Maybe the second speaker will yield more info. As for the woofer, I can't see any stamping of part number on it, but here is a better pic of the magnet for possible identification. and the positive sticker WAS there before the glue app for the missing screen. As far as the inductors, I see no markings to id them either. Usually black magic marker hand written on plastic, but not on these. I could easily release the spring clip and see if there are any markings on the bottom. Here by the way is a full shot of the crossover as well. I suspect the orange and purple caps can stay but the 4uf "Industrial" cap is suspect to me and can easily be replaced if you can give some guidance there please. I am also curious about the resistor. On my first set it was an actual sand filled resistor, and on this one it just seems to be a specific length of wire wrapped and threaded through a small piece of hard board type material. Doesn't seem to be anything "electronic" about it, but what do I know. Should I cut that out and install an actual resistor? Link to comment Share on other sites More sharing options...
stupidhead Posted February 14, 2016 Author Report Share Posted February 14, 2016 12 hours ago, owlsplace said: Congrads, Jeff on your number two set of AR-5's. I passed on a number four set recently, then changed my mind only to find out I was too late. I'm guessing these are a bi-product of the Norwood shuffle. They look great to me and I'm guessing again that they still have wax caps. Roger Thanx Roger, I know you have a soft spot for the 5's. I have spent a little time on the cabs and I am very pleased with their condition. They aren't perfect, but they are far from ratty. Here is a pic of one of the bottom edges and as you can see there is only slight separation. Pretty good work by the cabinet maker as well. Link to comment Share on other sites More sharing options...
RoyC Posted February 14, 2016 Report Share Posted February 14, 2016 6 hours ago, stupidhead said: Hi Roy, Thanx for chiming in. So the handful of insulation under woofer was done on other 5's too, interesting. I often wonder about what motivates some of these anomalies. Maybe the second speaker will yield more info. As for the woofer, I can't see any stamping of part number on it, but here is a better pic of the magnet for possible identification. As far as the inductors, I see no markings to id them either. Usually black magic marker hand written on plastic, but not on these. I could easily release the spring clip and see if there are any markings on the bottom. Here by the way is a full shot of the crossover as well. I suspect the orange and purple caps can stay but the 4uf "Industrial" cap is suspect to me and can easily be replaced if you can give some guidance there please. I am also curious about the resistor. On my first set it was an actual sand filled resistor, and on this one it just seems to be a specific length of wire wrapped and threaded through a small piece of hard board type material. Doesn't seem to be anything "electronic" about it, but what do I know. Should I cut that out and install an actual resistor? Geoff, The added insulation was most likely meant to adjust "Q" (very simply put... bass character relative to "boominess"). Placing damping material up against the back of a woofer is one way to affect this parameter. The woofer's date is consistent with other items such as the Sprague caps and larger inductors (I can tell from the photo that they are the later inductors). We may know more when you open the other cabinet. The 4uf Industrial Condenser cap was used in all 5's, and actually held up very well, though it would be prudent to replace them while the cabinets are open. The nichrome wire resistor is excellent and should stay put. These are found in the vast majority of AR-3a's and 5's and have proven to be very reliable. The AR-3a's resistor is .5 ohm and the AR-5's is 1.5 ohm. If you were to see corrosion at the rivets, it would be prudent to clean them and take a reading with your ohmmeter. Yours look fine. Your 5's are very nice, and worthy of a careful restoration. I'm looking forward to your progress! Roy Link to comment Share on other sites More sharing options...
ra.ra Posted February 14, 2016 Report Share Posted February 14, 2016 Nice follow-up, Geoff, and thanks for the great pics. You have a really fine pair there. About the woofer, I know you have several pairs of 2ax's (at least one with later foam woofer?), so now that Roy has identified magnet size as being the prime identifier of the early 5 woofer, perhaps you can simply compare these AR-5 woofers with those from the foam 2ax. Roy has also pointed out the differences in coils found in the AR-5 and based on the info in Tom T's AR inductor coil chart, I would've thought that there might have been an obvious visual difference in physical size. However, after looking at these two AR-5 crossovers using different coils and then comparing to yours, it would take a sharper eye than mine to make a visual determination of which coils you have in this pair. From that coil chart: Old: #6, 1.37mh, 240 turns and #8, 3.00mh, 335 turns New: #11, 2.30mh, 300 turns and #10, 3.83mh, 370 turns. Link to comment Share on other sites More sharing options...
owlsplace Posted February 14, 2016 Report Share Posted February 14, 2016 Ah, you have the Sprague caps and the ICC 4MFD foil cap. Have to wonder how the switch to electrolytics in the later version affected the overall sound, then as Robert pointed out the coil change. I have one set with the old coils and one set with the Sprague caps. I am planning on getting back into these this year and wanted to try a little bi-/tri-amp experiment. I already picked up the electronic crossovers and the amps. A few other things to put together before getting into it. The last set I picked up are going to end up with AR-8 woofers and the HiVi tweeters. Some feel the alnico woofers sound better than the ceramic -- we'll see -- well, maybe as the alnico set has JBL surrounds and the ceramics have the Boston FF surrounds -- variables are the spice of life As for the 4MFD cap I used a Carli 3.9MFD. You can probably get some epoxy into the edge split on the cab split to stabilize it. Not much to go wrong with the 1.5-ohm Nichrome resistance wire so I don't think you gain anything by replacing it. Added: I didn't see RoyC's post. I'm pretty sure the wire resistor is 1.5 from memory. I always thought the added fiberglass pad behind the woofers was to keep the lead wires from vibrating against the magnet but I've never seen loose fill in that location. Enjoy, Roger Link to comment Share on other sites More sharing options...
RoyC Posted February 14, 2016 Report Share Posted February 14, 2016 1 hour ago, ra.ra said: Nice follow-up, Geoff, and thanks for the great pics. You have a really fine pair there. About the woofer, I know you have several pairs of 2ax's (at least one with later foam woofer?), so now that Roy has identified magnet size as being the prime identifier of the early 5 woofer, perhaps you can simply compare these AR-5 woofers with those from the foam 2ax. Roy has also pointed out the differences in coils found in the AR-5 and based on the info in Tom T's AR inductor coil chart, I would've thought that there might have been an obvious visual difference in physical size. However, after looking at these two AR-5 crossovers using different coils and then comparing to yours, it would take a sharper eye than mine to make a visual determination of which coils you have in this pair. From that coil chart: Old: #6, 1.37mh, 240 turns and #8, 3.00mh, 335 turns New: #11, 2.30mh, 300 turns and #10, 3.83mh, 370 turns. Agreed, the bobbin size can make it hard to determine the coil size when comparing photos, but in Geoff's case the later copper colored wire, the Sprague caps, and driver date stamps make the case for the later inductors. Also, AR coils were not marked as often in this time period. It appears the coil size increased in cabinets with serial numbers around 20,000. The 10 inch AR alnico magnet woofer is still somewhat of a puzzle. The earliest AR-5 woofer not only had a larger magnet, but also a dome rather than the typical flat dust cap. Another woofer with the common flat dust cap, but slightly larger/heavier magnet shows up in the early 70's. I recently worked on 2 pairs of AR-2x's (not 2ax's) having this woofer, and found it in a pair of LST-2's. It is more sensitive than the more common woofer with the smaller magnet. I haven't seen enough of them to draw any conclusions as to what models had this woofer as original equipment. By the mid 70's it appears all models with 10 inch alnico magnet woofers were being equipped with the typical AR-2ax woofer with the smaller magnet and flat dust cap. Roy Link to comment Share on other sites More sharing options...
RoyC Posted February 14, 2016 Report Share Posted February 14, 2016 1 hour ago, owlsplace said: Added: I didn't see RoyC's post. I'm pretty sure the wire resistor is 1.5 from memory. I always thought the added fiberglass pad behind the woofers was to keep the lead wires from vibrating against the magnet but I've never seen loose fill in that location. Enjoy, Roger I corrected my typo...The resistor is indeed 1.5 ohm. A wad of fiberglass is often found wrapped around the woofer wires in KLH speakers, but I've only seen a pad of fiberglass placed behind AR-5 woofers. It isn't very much material, so your guess is as good as mine. Whatever the reason, I'm sure it was deliberate. Roy Link to comment Share on other sites More sharing options...
stupidhead Posted February 15, 2016 Author Report Share Posted February 15, 2016 So I hope to crack open the second speaker today and I am anxious to see what will be revealed. I will pay particular attention to the wad of stuffing under woofer, and particularly the orientation in relation to the wiring. On 2/13/2016 at 5:14 PM, RoyC said: Hi Geoff, Your specimens are very consistent with all the 5's I've seen, including the fiberglass on top of the Kimpac, though the missing screen section on the woofer is unusual. Perhaps this speaker was repaired at the factory early on. The woofer's crossover inductor and one of the midrange inductors were changed in the 5 along the way, as was the woofer itself. The earlier woofer had a larger magnet than the much more common AR-2ax woofer. I'm interested to know the numbers on the coils in this pair. Based on the serial numbers I suspect it will have the later #10 and #11 coils. Roy I did remove the spring clip on the two inductors and in fact they were marked with the black marker on the underneath face. They are 10 and 11 respectively. 18 hours ago, ra.ra said: Nice follow-up, Geoff, and thanks for the great pics. You have a really fine pair there. About the woofer, I know you have several pairs of 2ax's (at least one with later foam woofer?), so now that Roy has identified magnet size as being the prime identifier of the early 5 woofer, perhaps you can simply compare these AR-5 woofers with those from the foam 2ax. I love a mystery. Here is a foam 2ax (serial 267335 dated Dec. '74) which seems to have the same basket, cone and dust cap but different magnet. and here is a woofer from the other 5's (serial 37919) and you commented on the two date stamps on the previous, this one has three! I am thoroughly confused. One other observation, maybe meaningless but the woofer in the current 5s has a curious light green paint remnant on the outside surface. Sort of blotchy paint application, but definitely there. If you review the pic above with reference for better magnet identification it can clearly be seen. 19 hours ago, RoyC said: Geoff, The added insulation was most likely meant to adjust "Q" (very simply put... bass character relative to "boominess"). Placing damping material up against the back of a woofer is one way to affect this parameter. The woofer's date is consistent with other items such as the Sprague caps and larger inductors (I can tell from the photo that they are the later inductors). We may know more when you open the other cabinet. The 4uf Industrial Condenser cap was used in all 5's, and actually held up very well, though it would be prudent to replace them while the cabinets are open. The nichrome wire resistor is excellent and should stay put. These are found in the vast majority of AR-3a's and 5's and have proven to be very reliable. The AR-3a's resistor is .5 ohm and the AR-5's is 1.5 ohm. If you were to see corrosion at the rivets, it would be prudent to clean them and take a reading with your ohmmeter. Yours look fine. Your 5's are very nice, and worthy of a careful restoration. I'm looking forward to your progress! Roy Roy, I am putting together a shopping list for caps and even though not stated just want to be sure. The only thing you recommend for the crossover is the 4uf replace and obviously the pots need work, but the other two caps stay and can't be bettered? I will leave the resistor alone! Thanx folks for the interest and I will check back in this evening. Geoff Link to comment Share on other sites More sharing options...
RoyC Posted February 15, 2016 Report Share Posted February 15, 2016 1 hour ago, stupidhead said: So I hope to crack open the second speaker today and I am anxious to see what will be revealed. I will pay particular attention to the wad of stuffing under woofer, and particularly the orientation in relation to the wiring. I did remove the spring clip on the two inductors and in fact they were marked with the black marker on the underneath face. They are 10 and 11 respectively. I love a mystery. Here is a foam 2ax (serial 267335 dated Dec. '74) which seems to have the same basket, cone and dust cap but different magnet. and here is a woofer from the other 5's (serial 37919) and you commented on the two date stamps on the previous, this one has three! I am thoroughly confused. One other observation, maybe meaningless but the woofer in the current 5s has a curious light green paint remnant on the outside surface. Sort of blotchy paint application, but definitely there. If you review the pic above with reference for better magnet identification it can clearly be seen. Roy, I am putting together a shopping list for caps and even though not stated just want to be sure. The only thing you recommend for the crossover is the 4uf replace and obviously the pots need work, but the other two caps stay and can't be bettered? I will leave the resistor alone! Geoff Geoff, By 1974 AR was using woofers with ferrite magnets as shown in your photos. Multiple dates stamped on them may have had something to do with inventory control and/or testing along the way. My experience suggests you could get away with all of the caps, but the prudent things to do while the cabinets are open would be to replace the 4uf caps, and measure the Spragues if you have a meter. Roy Link to comment Share on other sites More sharing options...
owlsplace Posted February 15, 2016 Report Share Posted February 15, 2016 I read somewhere recently that the 2ax switched over to the 5's woofer around serial number 125000. Looks like the 5's used three different woofers during their run which may be the reason for the inductor change. Need a look at the early woofer as I haven't seen one and I would imagine the serial numbers would be from the first two years of production. Roger Link to comment Share on other sites More sharing options...
ra.ra Posted February 15, 2016 Report Share Posted February 15, 2016 Agreed, the history and development of this first 10" foam woofer is a bit confusing, and there do appear to be several variants. Roy's mention of an alnico woofer in the LST-2 was surprising, but unless I am missing a fourth alternative, these can be summarized as: 1. dome cap, large alnico slug magnet 2. flat cap, smaller alnico slug magnet 3. flat cap, square ferrite magnet Digging thru the drawings in the Library provides some further material for conjecture, much of which seems to support Roy's comment that changes occurred in the 1973-74 period. The earliest drawing for the 10" 200004 woofer (ferrite) has an early '73 date, as does the model AR-8 speaker assembly drawing which lists the 200004-1 version of this woofer. By mid '73, the 04 woofer drawing has a revision note which suggests that the 04-2 and 04-3 part numbers were added for AR-5 and AR-2ax usage. This same drawing includes mention of this driver being used in the LST-2 as well as the AR-12 and AR-14, models which were brought to market a few years later. Another revision note from early '77 denotes the 04-1 assembly has been deleted, suggesting to me the end of production for the AR-8 speaker. Small segments of AR literature attached. The first is a good pic of an early AR-5, with domed cap. Second pic is from '71 literature, also with domed cap. Third pic I think is from a Euro publication, and shows the flat dust cap and configuration we are most used to seeing. One curious item is that second '71 pic - - it shows mid and tweeter in-line much the way the 2ax baffle board is formatted. Link to comment Share on other sites More sharing options...
RoyC Posted February 15, 2016 Report Share Posted February 15, 2016 2 hours ago, ra.ra said: Agreed, the history and development of this first 10" foam woofer is a bit confusing, and there do appear to be several variants. Roy's mention of an alnico woofer in the LST-2 was surprising, but unless I am missing a fourth alternative, these can be summarized as: 1. dome cap, large alnico slug magnet 2. flat cap, smaller alnico slug magnet 3. flat cap, square ferrite magnet ra.ra, The "larger" magnet woofer I was referring to had a larger alnico (not ferrite) magnet and flat dust cap. I have two of them here with date stamps of May 11, 1971 removed from a pair of AR-2x's. I don't know if it is the same as the one with the dome dust cap. Also, the very first AR-2ax foam surround woofer had a wider basket (but the more typical smaller alnico magnet), with the same size mounting flange as that of the cloth surround woofer that preceded it. It would have been the woofer the AR-2ax was equipped with at the time of the introduction of the AR-5. These woofers would technically make at least 5 versions of the 10 inch woofer with a foam surround used in the 70's Roger, It would be more accurate to say the AR-5 began using the AR-2ax woofer...not vice versa. Where did you read this was done at AR-2ax serial number 125,000? Most AR-5's are equipped with the smaller alnico magnet 2ax woofer. At some point, near the end of production of each model, both were using the ferrite magnet version of the woofer (and changes were made to the 2ax midrange to compensate). Geoff's 37919 AR-5 with the ferrite woofer would likely have been manufactured in the last year of AR-5 production, as there were less than 50,000 manufactured. The response of the later ferrite magnet woofer and the large alnico magnet/flat dust cap woofer is very similar....much more so than the smaller alnico magnet woofer. Roy Link to comment Share on other sites More sharing options...
stupidhead Posted February 15, 2016 Author Report Share Posted February 15, 2016 Thanx rara for the info. I am thankful it lives in this thread for future reference. A thought occurred to me about all these variations, and the similarities but varying part numbers depending on the actual model being assembled. Possibly the 2ax and 5 ten inch woofer are actually identical and the part number difference is a parts dept. thing where the part number of woofer was a "kit" which got the requester the driver and proper coil as well? Wouldn't it be nice to come upon a stash of 8207002-0, I could find something to do with some of those! Roy, I just saw your above response and your reference to basket variations has me wondering something. When replacing the surround, which was filled filet BA from Larry, it just seemed like I didn't have the depth of contact of the surround to basket as I have on others. A tiny difference but I recognized it, I think! I was able to get into the second cabinet today and while there is much the same, there are definitely some detail differences. Also a little more commentary on my impressions of the assembly process at the factory. First off, I hadn't really given this more than a glance and hadn't really looked close. A closer look tells me the mortite application was cleaned up after woofer installation, but then on the last screw I saw a snap under the frame edge and realized it was foam! out pops the driver and I was anticipating the wad of insulation.... but it wasn't there. Dinner is ready, I'll be back. Link to comment Share on other sites More sharing options...
owlsplace Posted February 16, 2016 Report Share Posted February 16, 2016 3 hours ago, RoyC said: .... Roger, It would be more accurate to say the AR-5 began using the AR-2ax woofer...not vice versa. Where did you read this was done at AR-2ax serial number 125,000? Most AR-5's are equipped with the smaller alnico magnet 2ax woofer. At some point, near the end of production of each model, both were using the ferrite magnet version of the woofer (and changes were made to the 2ax midrange to compensate). Geoff's 37919 AR-5 with the ferrite woofer would likely have been manufactured in the last year of AR-5 production, as there were less than 50,000 manufactured. The response of the later ferrite magnet woofer and the large alnico magnet/flat dust cap woofer is very similar....much more so than the smaller alnico magnet woofer. Roy Hmmm, the new woofer was one of AR's ad points for the 5 when it came out in 1968. The new 2ax happened around 69-70. I am assuming the new 2ax used the 5's woofer from that timeline. The devil must have my ear as I'm also remembering an AR-5 label wit a serial over 50000 ... it should be here. I can't find the reference I mentioned at the moment but it must be here somewhere as this is the only place I read about vintage AR's. Here is TomT's timeline: Here is another mention of the 2ax transition. I'm assuming that the 5's dome tweeter was also used after 125000 in the new version. I just looked at the last 5's that I didn't rebuild yet, serial 11000+, circa 1970, that had the serial stamped into the cabinet under the label. One woofer was fried and the other showed signs of overheating so I decided to use the AR-8 woofers. These would have been made towards the end of the second year of production. They appear to be the same as the alnico woofers in the unfinished pine cab 5's that started this whole odyssey for me. Roger Link to comment Share on other sites More sharing options...
RoyC Posted February 16, 2016 Report Share Posted February 16, 2016 1 hour ago, owlsplace said: 1 hour ago, owlsplace said: Hmmm, the new woofer was one of AR's ad points for the 5 when it came out in 1968. The new 2ax happened around 69-70. I am assuming the new 2ax used the 5's woofer from that timeline. Hmmm, the new woofer was one of AR's ad points for the 5 when it came out in 1968. The new 2ax happened around 69-70. I am assuming the new 2ax used the 5's woofer from that timeline. Roger, The first 2ax woofer with a foam surround had a wide basket flange and a smaller magnet than the AR-5 woofer. The 2ax cabinet hole was larger than the 5's, so it was not even possible for the woofers to be interchangeable at that time. In fact, below is what Tom said about the AR-5 woofer in the link you provided....though he fails to mention the basket size difference. I'm sure he meant to say "mid-70's" in the last sentence, as these models were distant memories by the mid-80's "...the 1970-version AR-2ax actually did not use the same woofer as the AR-5. There were some subtle differences in the cones and voice coils between the two and the crossover frequencies, of course, were different. The AR-2ax woofer was #200004-2 and the AR-5 (and LST/2) had #200004-3 (later #1200004-2 and -3). By the mid-80s, however, all the 10-inch woofers for the AR-2ax, AR-5, AR-8, AR-12 and AR-LST/2 were all the same, and all by this time had the ceramic magnet structures." We should also bear in mind that the 1979 parts list being referred to in this thread was published around 5 years after these models were discontinued. By that time ALL service replacement woofers were the ferrite/ceramic magnet version regardless of part number. I have worked on many of both models and have had a number of discussions with Tom since that 2003 thread. The AR-5 started out with a different woofer, which was later dropped (according to Tom) in favor of the 2ax woofer by sometime in late '71 or early '72. That woofer was essentially the same as the wide-flange/smaller magnet 2ax woofer mentioned above, but with a standard size basket. These woofers are very common and I've seen many of them in both models. This also appears to be when the AR-5 woofer crossover coils were changed. The 2ax began using the same tweeter as the 5 upon the introduction of the wide flange/foam surround 2ax woofer in 69-70. I agree, Roger, I should have said around 50,000 AR-5's were manufactured. I recall seeing one listed on Ebay a few years ago with a serial number just over 50,000. Up until that time Tom had assumed there were less than that based on information in his files. Roy Link to comment Share on other sites More sharing options...
djcheung Posted February 16, 2016 Report Share Posted February 16, 2016 I refoamed a pair of AR5 last year. Looking at the woofer connection, the polarity seem to be different from yours. Any thoughts ? There is a problem uploading the pic. Link to comment Share on other sites More sharing options...
owlsplace Posted February 16, 2016 Report Share Posted February 16, 2016 2 hours ago, djcheung said: I refoamed a pair of AR5 last year. Looking at the woofer connection, the polarity seem to be different from yours. Any thoughts ? There is a problem uploading the pic. RoyC recommends checking the polarity markings of these using a battery as they were not always marked correctly. It seems a 10" woofer collection would be of some interest if anyone were to put together an AR museum I will definitely be keeping an eye out for the early AR-5 woofer that RoyC mentioned. Roger Link to comment Share on other sites More sharing options...
djcheung Posted February 16, 2016 Report Share Posted February 16, 2016 Thanks Roger, I will check it this evening. Still can't upload any pictures !!! Link to comment Share on other sites More sharing options...
stupidhead Posted February 16, 2016 Author Report Share Posted February 16, 2016 Good morning folks. Sorry 'bout not finishing my post last night but dinner and then some CL transaction activity last night as well, and then this morning I had 2" of snow with a 1/2" of an ice crust on top. Wasn't expecting that and I hadn't positioned vehicles in my normal snow blow configuration. Weird winter so far and I'll be glad when it is over. I seem to be liking winter less and less the older I get! So I see more insights about these various progressions of drivers with AR and links to some great threads with much interesting info. Has anyone actually tried to piece all of this info into some sort of a spread sheet? As for the current project, there are more observations. As my previous post showed, the date on this second woofer is Nov. of '72. More in line with the dates on the mid and high from first. This supports Roy's previous suggestion of the mortited woofer was worked on early on at the factory, possibly a final QC failure as the dates on first woofer are a couple months later? I also see the green splotches on this second woofer, similar to the first. I wonder if this was deliberate or is this just some sort of oxidation and in fact not paint? Keeping with the dating theme, here are some shots of the other driver's dates. I have no idea what the time line from driver production to speaker build was in this era, but all drivers in this one are dated Nov. of '72. These specimens are only 7 apart and I would assume were built at pretty much the same time frame. Something I noticed on the first which I didn't document was the way the xover was thoroughly stuffed with insulation, I assume to prevent any rattling and to have as much material in there reducing any open spaces. This picture is after removing any and all loose insulation. After digging out all this stuffing, there is nothing different about this board than the first. A little corrosion evident on one of the pots terminals, but no surprises. One additional observation however, the 24uf cap is blue on this one and orange on the other? Probably means nothing but figured I would mention it. One final observation for now, I almost didn't notice but the dust cover on this second one was clearly (but subtly) identified with a contrasting marker. With all the variants of the 10" maybe this was a way to keep things straight, at least at that moment in time. Putting a shopping list together and will extract the pots and inspect. Roy, I do have a Fluke 115 which can measure caps but I am dubious about cutting wires that I don't need to. Seeing as the Spragues are strapped down and sturdy I suppose de-soldering would be pretty easy. I will probably effort that unless there is a simpler way. Geoff Link to comment Share on other sites More sharing options...
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