nmerrill Posted February 28, 2011 Report Share Posted February 28, 2011 Hello y'all.New member, but I've read plenty here for a while. Hope someone can educate me a little.I seem to find surprisingly little info on the AR5, compared to the other models.I've finally found time to dig into a pair of AR5s I acquired several years ago. I've found a discrepancy in the crossovers from the standard diagram. The coils are not the 10 and 11, but a 6 and 8.Was this an earlier version? The caps are all as expected.The speakers are serial numbers K 13582 and K 13589 (nearly sequential!)Also, one woofer has a slightly different construction - there is no round circle on the back of the magnet, and the electrical connection is different. One is clearly stamped Apr 2 1970The other one actually has two date stamps - Dec 9 1960 (?) and then Apr 2 1970 The double dated driver does not have the little circular mark on the rear of the magnet, and has a different electrical connection than the other two drivers I have - I also have a newer cab that I found as an orphan.What do these stamps actually represent?Any way to tell if one of these was a replacement at some time? Here's a few pics.This is the first step in my full AR system restoration - I've got an Amp, and turntable waiting.Thanks!Nat Link to comment Share on other sites More sharing options...
genek Posted February 28, 2011 Report Share Posted February 28, 2011 The Dec 9 date looks to me like 1969. Link to comment Share on other sites More sharing options...
RoyC Posted February 28, 2011 Report Share Posted February 28, 2011 Hello y'all.New member, but I've read plenty here for a while. Hope someone can educate me a little.I seem to find surprisingly little info on the AR5, compared to the other models.I've finally found time to dig into a pair of AR5s I acquired several years ago. I've found a discrepancy in the crossovers from the standard diagram. The coils are not the 10 and 11, but a 6 and 8.Was this an earlier version? The caps are all as expected.The speakers are serial numbers K 13582 and K 13589 (nearly sequential!)Also, one woofer has a slightly different construction - there is no round circle on the back of the magnet, and the electrical connection is different. One is clearly stamped Apr 2 1970The other one actually has two date stamps - Dec 9 1960 (?) and then Apr 2 1970 Welcome to CSP, Nat!You have early versions of the AR-5. Somewhere before serial number 20,xxx, the coils where changed to #10 and #11. It is not unusual to see two (or more) dates on AR drivers, but I don't know the significance of this. I suspect they indicate date of manufacture of the woofer (1969...not 1960) and the date of use (1970). The dates do correspond with the time AR-5's with your serial numbers would have been manufactured. Foam surround woofers were not used in AR speakers before 1969, and some changes occurred as they evolved. It is very likely your woofers are original, or identical to those originally used in cabinets with your serial numbers.Roy Link to comment Share on other sites More sharing options...
Steve F Posted February 28, 2011 Report Share Posted February 28, 2011 Remember in their 1974 lit, AR changed the x-o specifications of the 3a from 575 to 525, and on the 5 from 650 to 550.When I wrote to AR to question that, they responded to me that those specs "reflected a change made some time ago," or something to that effect.Their actual quote may be found in the Library under "Letters to Steve F."Steve F.P.S.-- The very sharp-eyed among us (or the totally obsessive, 'get-a-lifers' among us, take your pick) will be quick to point out that the LST-2--which was based on the AR-5's drivers--had a woofer-to mid x-o spec'd at 525 Hz, which doesn't correspond to anything logical. Obviously an internal editing error that went forever uncorrected. Feel free to peg me into whichever category you like. Link to comment Share on other sites More sharing options...
nmerrill Posted February 28, 2011 Author Report Share Posted February 28, 2011 Now that y'all mention it, that does look like a 9! And clearly makes more sense.Thanks for the info. I'm glad that the pair appears all legit.Is there a known reason for the change in the coils?I was rather bummed when I opened one cabinet up. Several years ago my then girl friend placed a bag of frozen rhubarb on the face of the speakers laying near the freezer (not unusual since I had about 12 pairs in the house).She then forgot to put it back in the freezer, and it melted all over the speaker (no grills on them).Well, I can't recall what I did at the time, or how much water I thought got in...When I opened that cab I found a horror show. The cross over pad was all green with mold. Everything metal was corroded...Luckily, I did score an orphan a while back that I'm going to use as a donor. I already managed to pull the crossovers out complete - was able to pull most of the staples out with only one bloody knuckle!Yes, I did still marry her!Next I'll swap over the coils so they match. Already have new caps to go in, and new surrounds.Any idea what type of glue they used to glue down the crossover pad?Thanks again!Welcome to CSP, Nat!You have early versions of the AR-5. Somewhere before serial number 20,xxx, the coils where changed to #10 and #11. It is not unusual to see two (or more) dates on AR drivers, but I don't know the significance of this. I suspect they indicate date of manufacture of the woofer (1969...not 1960) and the date of use (1970). The dates do correspond with the time AR-5's with your serial numbers would have been manufactured. Foam surround woofers were not used in AR speakers before 1969, and some changes occurred as they evolved. It is very likely your woofers are original, or identical to those originally used in cabinets with your serial numbers.Roy Link to comment Share on other sites More sharing options...
RoyC Posted February 28, 2011 Report Share Posted February 28, 2011 Is there a known reason for the change in the coils?Next I'll swap over the coils so they match. Already have new caps to go in, and new surrounds.Any idea what type of glue they used to glue down the crossover pad?Thanks again!Nat,AR changed woofer inductor coils in most of their models in the early 70's (2ax, 4x, 5, and 3a). The AR-5 also had one of the midrange coils changed. There were several iterations of the AR-6 crossover. All of the reasons for doing so are not clear, but there was certainly some tweaking to the original designs going on.The resistor wire shown in your photo is 1.5 ohms in series with the midrange. Its counterpart in the AR-3a is .5 ohms.AR used hot glue for the crossover boards.Roy Link to comment Share on other sites More sharing options...
RoyC Posted February 28, 2011 Report Share Posted February 28, 2011 P.S.-- The very sharp-eyed among us (or the totally obsessive, 'get-a-lifers' among us, take your pick) will be quick to point out that the LST-2--which was based on the AR-5's drivers--had a woofer-to mid x-o spec'd at 525 Hz, which doesn't correspond to anything logical. Obviously an internal editing error that went forever uncorrected. Feel free to peg me into whichever category you like.Hmmm...just doing your job as a very excellent AR historian and hobbyist, Steve! Roy Link to comment Share on other sites More sharing options...
dynaco_dan Posted March 1, 2011 Report Share Posted March 1, 2011 Hmmm...just doing your job as a very excellent AR historian and hobbyist, Steve! RoyHi thereIt is great to see Roy and Steve contributing so much to this topic, thank you. Link to comment Share on other sites More sharing options...
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