JKent

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About JKent

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  • Birthday July 14

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  • Gender Male
  • Location Northwest NJ

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  1. KLH 24 Capicitors Confusion

    17s are really nice. Be sure to find all the caps (I think one is inline with the tweeter lead). There should be a schematic in the CSP Library. Keep us posted! -Kent
  2. Again--please refer to the restoration guide. The original potentiometers are no longer available. People have used Ohmites (expensive) or Chinese knock-offs but both require fashioning some sort of enclosure to keep the fg out (see my thread). There is also a fancy stepped attenuator that some have used. Best replacement is cheap ($4) L-pads, available from Parts Express or Madisound. You should add a resistor to the L-pad, but still cheap. Caps can be found at those same sites. Common wisdom is to use film caps for low values (say under 20uF) and non-polar electrolytics for high values. You may want to use film caps for everything on these speakers but the bigguns get expensive. -Kent
  3. Hi and welcome to CSP! Be SURE to read the AR-3a restoration guide: http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/ It will explain how to repair or replace the pots (attenuators) and replace the caps and tweeters. You will also get a lot of help here. You ask a tough question. The original 3 seems to fetch a higher price and the drivers are hard to find. I have some 3s that I converted to 3a because I had one bad tweeter and one bad mid and it was difficult to find replacements. The project is described here if you are interested: As far as replacement drivers, Roy is the man to consult but I can tell you the 3 tweets can be found because they were also used in other AR speakers. 3a tweeters are unobtainium but can be replaced with Hi-Vi, a modern tweeter that works very well (I have them in mine). The mids in the 3 are ridiculously heavy, unobtainium, and connected with hair-thin aluminum leads--horrible to work on. The 3a mid is easier to work with and more available because the same driver was used in the 10-pi, 11 and others IIRC. The woofers in the 3 and 3a may be identical (cast aluminum frame and cloth surround) or, if you have a later 3a it may have a steel frame and foam surround. I love the cloth-surround woofers. Hope this is somewhat helpful and I'm sure other members will chime in. Read that restoration booklet! -Kent
  4. KLH Model Fourteen B restoration pics

    I don't think so. I believe the 2 4" drivers are wired in series and put in a bigger, ported box to give the speaker more "oomph." The "crossover" is, I believe, an LCR filter network. KLH used two 3" drivers in series in the early Model Eight radio speaker. Later Eights had just one 4" driver--the same driver used in your Fourteens. The Model Twenty-One radio also used one 4" driver. FYI, that same driver was used as the mid-range in the excellent Five and Twelve speakers. I just looked up your thread on AK (many of us are on both forums) and see you also scored a Twenty-Seven receiver. Nice find! I have one on my shelf, awaiting restoration. -Kent
  5. KLH Model Fourteen B restoration pics

    Any of those you list are fine. So are Dayton. Don't worry about the voltage--anything 100vdc or more is plenty. You could also use Erse PulseX or PEx from erseaudio.com or Carli or Bennic from Madisound. No need to spend a lot of money. Or...if you have a local electronics parts shop ask for a mylar 1.0 microfarad cap. Might be radial instead of axial but it will work. Could look like this: -Kent
  6. I used to use Antique Oil on my KLH Model Eight radio restorations because I was afraid of lacquer but I'm now a convert. I use the Minwax GLOSS in the black can. I have not tried Deft but can tell you I had terrible results with Rustoleum. You have to work quickly because it dries so fast but that also means no dust. I guess you have to get the hang of how "wet" to put it on because as you discovered you can get runs if it's too heavy. Keep the can moving but spray in one continuous line (say, left to right) then stop and start another pass--don't keep spraying back & forth. Also be sure to check the distance of the can from the surface. I think about 8 to 12" is right but read the directions. And yes--8 or more light coats is about right. I used to build model cars as a kid so maybe there's some residual "muscle memory" of the right technique You can also Google "what causes orange peel?" or similar wording. Most of the articles apply to real spray guns but I think some will be useful for your rattle can use. This one, for example: http://lumberjocks.com/topics/33594 Temperature, humidity and distance are 3 big factors. You don't want the solvent to dry mid-air, leaving lumpy deposits on the surface. And maybe it's the Satin that doesn't work well. I recommend Gloss. I think that's what the original lacquered finishes were but if it's too shiny for your taste you can can use rotten stone or very fine wet sandpaper to tone it down. btw--I would NOT put lacquer over oil--that's just asking for adhesion problems. Sorry you're having such a rough time of it. Good luck getting it right. -Kent
  7. KLH Model Fourteen B restoration pics

    That can't be right. Please post a photo.
  8. KLH Model Fourteen B restoration pics

    Hi Pierre and welcome! KLH made a couple of Model Fourteens. I've owned both and I think they were essentially the same except for shape. The Fourteens were flat (ish) and could be hung on a wall. The "B" version you have has the same dimensions in width and height as the Eleven-W, Twenty-One extension speaker and others that were used with compact systems but it's twice as deep. And while those other speakers were acoustic suspension designs the 14 and 14B were ported. The drivers are the same full-range 4" one used (singly) in the late Model Eight, Model Eleven (suitcase) and Eleven-W, Twenty-One radio etc. Nice speakers with lots of sound! Oh, and another difference: Except for the Model 708 all of those variations on the Eleven-W were run flat out with no filter. The Fourteens, as you show, had filter networks. It would be a good idea to replace the caps. Keep us posted! -Kent
  9. Repro Metal labels: KLH, Advent, AR

    Send me a PM through CSP -Kent
  10. Thanks guys. This is a great and friendly forum and I'm very happy that I could help a member's widow. I happened to be close by but I know many of our colleagues here would do the same. Off on a tangent: Since we moved to a log cabin 12 years ago I've been without a basement or garage, hence no workshop. As I became more involved in this hobby I took over the rec room and turned it into the wreck room My wife was tolerant but exasperated so she suggested dividing the room so we could keep a guest area in one half and I could have a shop/storage room in the other. Fortunately the room is large. Still organizing the space. My bro-in-law is building some 4' high bookcases to define the space and provide more storage without walling me in. There are still more KLH radios and some speakers to be stored while awaiting restoration. Almost everything will be restored and sold (to finance the purchase of more vintage stuff of course! It's a great hobby). So here's another shot, showing the bench (built for me by my dad when I was about 12 and building model cars), one of Kathy's speakers on the bench and the other on a tarp, and a groovy 1960s KLH sign.
  11. Finished! I wantto get them back to Kathy ASAP so ... It went pretty smoothly. Here are some notes: Joe had retained the original dust cap. Maybe he used a test tone. I cut the dc back and shimmed, then glued it back when finished with the re-foam so the woofers would both look the same. I goofed when I went through Joe's box of caps. Thought I had everything I needed but the 24uF had already been removed. No big deal--I had a couple of 16uF and 8uF caps on hand so just paralleled them. Some of the poly stuffing was missing from one speakr but again, I had some on hand. Also missing were the 4 woofer screws from the open speaker. A trip to my local hardware store turned up some nice socket head 10-24 machine screws so I replaced all 8. The foam gaskets were totally flattened so I replaced those with PE's stick-on gaskets. You can see the old gasket in this shot of the new capacitors. No bonus points for neatness--there are some things my arthritic fingers refuse to do (I'm sure some of you can identify with that). I checked the old caps and found the 24uF was seriously out of spec (measured 33.9) but the 80uF cans were OK (81.4 and 85.4) and, surprisingly, so were the 4uF and 8uF black and red Callins PVC caps, which are notorious for leaking. But I think the new film caps were a good idea. These will go to Joe's daughter and, maybe, to the next generation as well. Finally, the foam diffraction rings on the tweeters were missing so I made some new ones from PE foam speaker grille. Probably not needed (Idon'thave them on my 91s) but I wanted to do these right. A little WD-40 removed an old label from the vinyl cabinet. Cabinets were otherwise in excellent shape so I cleaned them and applied some Armor-All. The grilles are perfect so I left those with Kathy. They sound great! Can't resist showing a bit of my new workshop. I compared the AR-92s with my AR-91s and the slightly smaller 92s do well in the comparison. In fact, they seem to have more bass. I'll check my 91s for air leaks but I suspect the perceived bass is actually midbass, giving the illusion of stronger bass but I can tell you on rock music the kick drum is moreprominent through the 92s. That's it! Plan to return them to Kathy & daughter in a day or 2. -Kent
  12. Picked them up today and got started on them (there was a little extra delay because we were having our rec room/my shop remodeled. These are the first project in the new shop!). Joe had refoamed one woofer and had all the caps. Had to decide whether to use 80uF NPEs or paralleled 40uF film caps. Kathy had all the caps and since these are to be heirlooms for their daughter I opted for all film caps. Today I refoamed the other woofer and started the re-cap. Will post photos after I make a bit more progress. -Kent
  13. Glue removal tips

    Stan makes a good point. If you were on this side of the pond I'd say send them to Bill LeGall. I had a pair of AR 12" woofers that looked awful, with a sloppily glued surround. The solvent-based glue was thick and gloppy. I decided not to tackle them and sent them to Millersound. Bill did his usual outstanding work! -Kent
  14. AR-2ax refurbishing and use question

    ooops. I wrote a reply about how you need to put in new caps. Then discovered that you did. Aleene's isn't strong enough to hold the caps. Best bet is either the nylon cable ties and mounting blocks or GOOP. Also, although respected members have warned against hot melt glue others have found no problem with it. I've used hot melt from time to time but still prefer the ny-ties. -Kent
  15. Korina Korina

    Congrats on a great score! See this thread: I "think" the newer tweeter ("mid") may have been factory installed in some cases while they were using up the old cabinets. You may want to listen to them as they are and see what you think. The double angled tweeters were meant for wide dispersion when the speakers are placed horizontally. You may also have oil caps in there. I'd suggest re-sealing the woofers with Roy's goo and clean or replace the pots. Tom would be the expert here but I suspect the Korina finish was not available on the "real" 2ax and it was rather rare on the 2a. A real collectible and another reason to consider leaving them as they are. Anyway, congrats on those! -Kent