82nd-EOD Posted April 10, 2021 Report Share Posted April 10, 2021 Hi, I am trying to find what is the truth as to what drivers are used in the KLH model #12's? I have a one set that has been rebuilt, And sound GREAT. A second set I just found for next to nothing, One of the woofers has been replaced with a newer 12 inch KLH driver. So now I am looking for a #12 woofer. I have people that say the drivers are the same as the #5, I have also other people that say the #5 and #12 are not interchangeable? After looking at the drivers I found that the tweeters for the #12 have M12 stamped in the front of the basket, Need to look close but they are on the model#12 tweeters the model #5 tweeters are not marked. The mids look the same on the #12 and #5. The woofers look the same except the ones in the model#12 are marked with a 12 and 24.6 or 26.6 in marker on the cone, The model #5 has no marks on them. Quote Link to comment Share on other sites More sharing options...
JKent Posted April 10, 2021 Report Share Posted April 10, 2021 Welcome 82nd I'm a fan of the Fives and Twelves and although I've restored a couple and recapped many I don't have any right now. KLH always spelled the model numbers out but let's use shorthand and call them 5 and 12. The driver question has been kicking around fo a long time and has not been fully resolved IMHO. Let's start with the mids because that's easy: They're the same. KLH called their 4" full-range driver the "Twelve point five" (no idea why) and started using it in the Model Eight tube radio when they ran out of 3" drivers. It was used as a mid in the 5 and 12 and as a full-range in the later 8, 13, 14, 15, 19, all 5 versions of the 21 radio and a few compact systems. The tweeters all look the same, with metal grilles, but some are painted black. That's not the difference. Model 5, 12, and 23 have a thin top plate above the magnet, all others have the same thickness plates above and below the magnet. The M12 tweeter was used in the Model Twelve. But in real world application it probably doesn't matter as long as the pair matches. This very long thread may give some clues about the difference. The thickness thing is hard to spot unless you compare them side by side. Color does NOT matter. https://www.audiokarma.org/forums/index.php?threads/klh-tweeter-id-and-repair.492609/ The 12" woofer: Of course it's not really 12" but that's what they called it. More like 10.75" Some 5s had woofers with square magnets and I have no first hand experience with those but they are not for the Model 12. Other Model 5s had round magnets, as did the Model 12 but the Model 12 woofer's magnet is about twice as thick. So no--they're not the same. There is a knowledgeable member on Audio Karma who claims later Model Twelves did use the same round magnet woofer as the Five. I have no way of confirming this but I do think that so long as the woofers match in any given pair of speakers it "may" not be a big deal. The markings in ink on the woofer cones are test measurements from the factory. I forget what they measured--mass or something. Check out this thread: btw--We like pictures but yours isn't showing up. Maybe too big. Resize jpg images to about 100kb or so. Kent Quote Link to comment Share on other sites More sharing options...
JKent Posted April 10, 2021 Report Share Posted April 10, 2021 One last comment (for now): Check out this KLH Service Bulletin http://www.classicspeakerpages.net/library/klh/other/klh_schematicsservice/klh_service_bulletin_60.pdf Re-sealing the cloth surrounds on KLH woofers can make a HUGE difference. Our RoyC makes the ONLY sealer you should ever use and it's sold by ebay seller Vintage-AR. Experience has shown that it's helpful on some AR woofers but not necessarily all (the AR-4 for example benefits little) but I can tell you it turns a KLH Model Five from a pretty good speaker into a great one. Quote Link to comment Share on other sites More sharing options...
JKent Posted August 2, 2021 Report Share Posted August 2, 2021 I'm going to hijack this thread for my latest KLH Model Twelve project. A fellow CSP member picked up a very nice pair and will be doing the cosmetic work himself but he sent me the contour boxes to rebuild. I'll let him chime in if he chooses to. He reported that one box was dead in the midrange. I've ordered new capacitors and resistors and am waiting for delivery but decided to tear apart the dead crossover while waiting. I tested the woofer, mid and tweeter outputs by connecting a full-range driver to the woofer and mid outputs and a tweeter to the tweet and found that the woofer output was OK but the mid and tweet were very weak. Pulled all the caps. Some were doubles but wired in parallel. I was amazed this crossover worked at all, given the readings. I even replaced the battery in my Capacitance meter and checked it on a new capacitor. So here are the readings: Marked Reading 3 MFD 0.02 2x2 MFD .001 .001 2x4 MF .002 .002 2x4 MFD .001 .002 2x4 MFD 1.02 0.62 50 MFD 2.9 50 MFD 4.4 Quote Link to comment Share on other sites More sharing options...
JKent Posted August 5, 2021 Report Share Posted August 5, 2021 The 2nd xo's caps weren't nearly as bad. Mostly off by 20-25% although one 2x4uF measured 0.18 and 0.13, and the 50uFs both measured in the 70s. I've mentioned this many times--I always replace the 5w resistors in these crossovers with 10w. Second photo below shows a resistor I found in a Model Twelve years ago. There are 7 resistors per box and at two bits each (Erse) it's cheap insurance: 2 15ohm, 2 10 ohm, 2 6ohm and 1 5ohm per contour box. Caps used this time were mostly from Erse: 2 50uF NPEs per box. The rest are all mylar: one 16uF mylar, three 4uF and one 3uF (a TI that I happened to have on hand). Tested the finished boxes with a full-range driver to make sure everything worked and they're both now loud & clear, ready to return to the owner. Quote Link to comment Share on other sites More sharing options...
RoyC Posted August 6, 2021 Report Share Posted August 6, 2021 19 hours ago, JKent said: Caps used this time were mostly from Erse: 2 50uF NPEs per box. The rest are all mylar: one 16uF mylar, three 4uF and one 3uF (a TI that I happened to have on hand). Nice work as usual, Kent. I typically don't comment on capacitors, but I would avoid Erse npe's in the future. Relatively recent measurements show them to be inconsistent, and never as good as their physically larger counterparts sold by Parts Express and Madisound (MDL brand). Erse mylar caps continue to be an excellent value. Roy Quote Link to comment Share on other sites More sharing options...
Troll Posted October 21, 2021 Report Share Posted October 21, 2021 I have two early (1968 vintage) KLH Model 12's. Both b ase speakers blown out. Any suggestions as to finding replacements? Quote Link to comment Share on other sites More sharing options...
JKent Posted October 21, 2021 Report Share Posted October 21, 2021 Ebay. Watch for Model Twelve woofers with the double magnet. A pair of Model Five or Twenty-Three woofers would probably be OK. Quote Link to comment Share on other sites More sharing options...
82nd-EOD Posted October 22, 2021 Author Report Share Posted October 22, 2021 Hello JKent, Are you able to rebuild two #12 boxes? And if so about what would a total rebuild cost. Thank you Chuck Quote Link to comment Share on other sites More sharing options...
JKent Posted October 22, 2021 Report Share Posted October 22, 2021 PM sent Quote Link to comment Share on other sites More sharing options...
jseehusen Posted December 16, 2021 Report Share Posted December 16, 2021 JKent Any chance you can email me the schematics for the KLH Model Twelve controllers? My speakers pro is updating my pair and this will save a couple hours of work for him. Thanks and Happy Holidays! Joe jseehusen@yahoo.com Quote Link to comment Share on other sites More sharing options...
JKent Posted December 17, 2021 Report Share Posted December 17, 2021 Sorry. I have never seen a schematic for the Model Twelve and it is certainly not needed for replacing caps and resistors. I do recommend replacing the 5watt resistors with 10 watt. Quote Link to comment Share on other sites More sharing options...
Zbigniew59 Posted January 27, 2022 Report Share Posted January 27, 2022 Hey guys ! My name is Zbigniew and I am from Poland.I have bought these wonderful speakers. They have beautiful chests,and fantastic sound.They are very rare in Poland, I waited six months for a friend to sell them to me. So far, I have listened to the model five,very good sound too, but that's not it Now I am getting on with the renewal of these speakers, I saw that the potentiometers are disconnected, I asked my friend what was going on( I attach photos), says he made them for a permanently flat sound, I'd like to go back to the original and be able to adjust the sound relative to my room. i watched all the photos on this forum but it's hard to see all the capacitor connections. maybe someone make a freehand drawing of what and how to connect ?? the capacitors used in one case are: 2x3,9 1x15 1x47 Thank you in advance for your help and best regards from Poland Quote Link to comment Share on other sites More sharing options...
JKent Posted January 28, 2022 Report Share Posted January 28, 2022 Oh dear! Great speakers but your friend made a mess. I've worked on a lot of these contour boxes and they are very complex. I've never found a schematic and I'm afraid you will never be able to re-wire everything correctly. You could watch ebay to see if some contour boxes come up for sale. That happens once in a great while. In the meantime the only thing I could suggest is that you try using a separate equalizer. Kent Quote Link to comment Share on other sites More sharing options...
Zbigniew59 Posted January 28, 2022 Report Share Posted January 28, 2022 Hi Kent thanks for the reply I have been looking for and watching ebay for quite some time in search of these crossover boxes. I know I know freehand drawing of connections is difficult and laborious I will think about using an external graphic equalizer. Best wishes Zbigniew Quote Link to comment Share on other sites More sharing options...
Zbigniew59 Posted January 28, 2022 Report Share Posted January 28, 2022 Hi Kent I have the Klh five undressed,will try to use these crossovers, What do you think about it? Quote Link to comment Share on other sites More sharing options...
JKent Posted January 28, 2022 Report Share Posted January 28, 2022 7 hours ago, Zbigniew59 said: I know freehand drawing of connections is difficult and laborious and unfortunately I don't have any Model Twelve boxes to look at. I sold mine and have restored some for others but I have none here. Model Five crossovers "should" work but they won' give the flexibility of the Contour boxes (or an EQ). Good luck. Kent Quote Link to comment Share on other sites More sharing options...
Zbigniew59 Posted January 28, 2022 Report Share Posted January 28, 2022 ok I understand, Thank you for your help Zbigniew Quote Link to comment Share on other sites More sharing options...
JKent Posted February 3, 2022 Report Share Posted February 3, 2022 There are 2 contour boxes on ebay today. Quote Link to comment Share on other sites More sharing options...
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