Robthomp

Instead of spending time trying to test the tweeters directly, which carries some risk, why not just proceed and replace the caps and clean the pots? You're going to want to do that anyway, and the probability is high that it will restore function. Rob

Thank you lakecat and ra.ra for the advice about grill cloth cleaning, and congrats larrybody on the AR4's. Ra.ra, that's a lot of great research on the grill cloth. Here are two pictures I took, one of the grill cloth on these 4's I just got, and one of Wichelt Lambswool linen from 123stitch. It looks like they have the same threadcount (~ 20 /inch) but the thread in the original cloth looks to be a smaller diameter than in the new stuff, so the amount of space between the threads appears to be greater. I assume that would affect the sound wave passing through the cloth, but what I don't know is if it's a difference that people can hear. I went ahead and removed the grill on the first speaker. I didn't have a dental pick, but I tried a variety of small screwdrivers, tweezers and needle nosed pliers. Unfortunately as you can see in my pictures, the cloth is not unscathed. In my defense, some of these marks, in particular the worst ones in the middle, were not due to my work, but simply are there because the staples were a little rusty and the thread was crushed under the staple, and so that's just the condition of the fabric with the staple removed. I'm not too concerned, I managed not to rip any holes, and those marks may be a little less noticeable after I clean them. A fifty year old object is bound to have some 'character'. The drivers appear to be in great shape. There's hardly any dust, and the surrounds have some suppleness.

That's what I originally thought. I just second guessed myself when this seller, who is not a hifi person per se, seemed a little concerned that I would monkey with them. Thanks for the tip on getting the grills off - that seems like it will work. I guess patience is key. How did you clean yours? When I cleaned my 4x grills I used Woolite fabric cleaner and it left some slight streaks and didn't get them much cleaner. Rob

Hi, I found a pair of AR4s on CL for not too much money so I got them. I have read that the AR4 is less common than the AR4x. I do a see quite a few 4xs on CL and the auction site, but not too many 4s. These have low serial numbers 00204 and 00221. When I went to get them I assumed I would be restoring them, but now I wonder what's more important -- getting them to sound wonderful, or keeping them original and untouched? My 4xs, after restoration, sound incredible. This seller, who has a house full of amazing vintage items, seemed a little dismayed that I might tamper with these. They certainly don't look like they've ever been opened - the grills are firmly stapled with many tiny, old staples. They don't sound wonderful - there's nothing coming from the tweeters. I presume the caps may be bad and the pots corroded. The grills are in good shape but terribly stained (although they're not as dark as they look in my bad pictures). The cabs are pretty good, they would clean up nicely. Getting the grills off without destroying the fabric seems like a challenge. I wonder what your thoughts are on restoring good sound vs. keeping a 'collectable' unmolested. Rob

Hi, I think I can ask a better question: I'm recapping these speakers. Should I replace the crossover in the 22 with the same one that's in the 22A? If the drivers are in fact identical, then presumably KLH decided the second crossover was an improvement, otherwise they wouldn't have put it in. On the other hand, if the drivers do not have the same electrical characteristics (even though they look the same to my untrained eye) or if the inductors have different values, then modifying the crossover in the 22 might be a bad idea. Rob

Well, I opened the Model 22 and Model 22A. The crossovers are different: 1) The drivers appear to be identical. The Model 22 drivers are stamped with 1968. The Model 22A doesn't have a date stamped on the drivers, but there is a stamp on the baffle board which contains the line STY 5 21 70, which I am guessing is a 1970 date? 2) The Model 22 tweeter is housed in a cardboard enclosure, the 22A tweeter is housed in a plastic one. 3) The woofer on the 22 is sealed with the usual bead of white putty seal, but the woofer on the 22A is NOT sealed with that stuff. Under the rim of the aluminum frame there is just a thin ring of foam stripping. 4) The Crossovers: the Model 22 has a simple first order crossover - a 4 muF capacitor in series with the tweeter, and a coil in series with the Woofer ( I do not know the inductance of the coil, it doesn't appear to be printed on it.) The Model 22A on the other hand in addition to the coil, has a 16 muF capacitor in parallel with the woofer, and an 8 muF capacitor and a 3 Ohm resistor in series with the tweeter. I have attached drawings I made of the schematics. I am learning a little bit about crossover design and I'm very interested in knowing what the effects would be of this crossover upgrade and why KLH went to it. Is it possible to generate the frequency response plots for these two crossover designs, assuming identical drivers, and compare them? Is the modified crossover in the 22A related to the fact that the woofer didn't seem to be sealed as well? Or is the woofer on the 22A supposed to be sealed but KLH just cheaped out by using a flimsy foam strip instead of the airtight putty? How good would your hearing, or listening training, have to be to hear the difference between these two crossovers? Rob

Also, the letter "A" on the back plate isn't part of the original lettering on the plate - it looks like it's stenciled on or something.

Hi, Today I just bought a pair of Model 22's from a guy on CL. The cabinets are in beautiful condition and they sound great. When I got home I realized that one is a 22 and one is a 22A. He advertised them as 22A. Does anyone know what the A designation is for and is there any difference? I can find references online to both but no mention of the difference, if any. The tweeter on the 22 is mounted on a white cardboard ring, the tweeter on the 22a is mounted on a black plastic ring. The woofer cones are slightly different colors. The particle board backs have slightly different colors. The cabinets and grills are absolutely identical but I don't know if the grills are original or if the cabinets were ever refinished. The serial number on the 22 is 23519 and on the 22A its 45037. Rob