mike stehr Posted December 30, 2007 Share Posted December 30, 2007 "I suggested replacing the autoformers because the winding on the originals is often not tight on the core anymore." How would the autoformer winding work itself loose from the core? Vibration from within the cabinet? It would seem they were wound rather loose if cabinet vibration changes how tightly the winding is coupled to the core........you sure they just were not wound sloppy from the get go? Quote Link to comment Share on other sites More sharing options...
Bill Hausmann Posted December 30, 2007 Share Posted December 30, 2007 OK.... I'm confused (not that hard to do)..... I would also like to do either an x-over upgrade or re-build. I have vint 81 with type B-2 x-overs. I also noticed that this was the only style to reverse polarity on the squawker and tweet. I read through all ALK's notes on his re-build. I also saw what Dean G said about "use Al's original design". Does that mean don't change out the 1.3Mhy's for 2.0 and 2.4's to smooth out the impedance mis-match? I usually drive my corns with EL34's or sometimes a Citation II so I'm not going for low volume. I know the cap's in those corns are tired. So it's probably time to do something with them. So for a re-cap (no pun intended): 1- Just a re-cap 2- Re-cap w/autoformer 3- Re-build with ALK (original) 4- Re-build with ALK (impedance improving) ....Thanks Quote Link to comment Share on other sites More sharing options...
fini Posted December 30, 2007 Share Posted December 30, 2007 "I suggested replacing the autoformers because the winding on the originals is often not tight on the core anymore." How would the autoformer winding work itself loose from the core? Vibration from within the cabinet? It would seem they were wound rather loose if cabinet vibration changes how tightly the winding is coupled to the core........you sure they just were not wound sloppy from the get go? You know, when I was young I was all wound-up tight. Now, since my crossover to vintage status, I'm a lot looser, to the core. Quote Link to comment Share on other sites More sharing options...
sherwoodhifi Posted December 30, 2007 Share Posted December 30, 2007 Zeno, Buddy, you are in luck, I have a set of Dean build modified type B network with VCaps. You are welcome to audition the crossover, send me a email. Bob Quote Link to comment Share on other sites More sharing options...
fini Posted December 30, 2007 Share Posted December 30, 2007 Bob, that's cool! You know, Josh is lending me some of his spare crossovers for my Khorns. Zeno and I will have to concoct something for you guys... Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 30, 2007 Author Share Posted December 30, 2007 Bob, that's cool! You know, Josh is lending me some of his spare crossovers for my Khorns. Zeno and I will have to concoct something for you guys... Hey fini, we could use my garage. My mom could help with the costumes. And I have that enormous box full of high voltage TV rectifier tubes! Let's concoct away..... Konconctaway....... -piypuolkpijoulipo & hdwytevyt Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 31, 2007 Author Share Posted December 31, 2007 Seriously, short of adding an Altec Midrange horn and driver on top, what are the optimum improvements that can be done to the Cornwall I while still containing everything in the original cabinet? So far I understand there is the crossover upgrades, the woofer and/or tweeter from Bob Crites, but what about a midrange horn which is the crux of the problem? Is there a practical way to replace the K55/horn with something better which can be easily retrofitted into the existing space within the cabinet? -mnbvcxz & asdfghhjkj Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted December 31, 2007 Share Posted December 31, 2007 Clip, Without a change to the box, or an external horn mount; (on top) you are very limited as to a midrange upgrade. BEC was installing a Pyle horn at one time. I thought it sounded pretty good, but it required a larger opening in the motor board. I think that that horn has been discontinued, but bet some are still floating around. Some CW motor boards are removable. If yours are, a new MB could be made so that the original could be reinstalled to stock. My ‘75’s are not. The port shelves are stapled and glued to the MB. Removal would be difficult and risky. With all due respect, the K600 is a nasty little thing IMO. Considering things mentioned in this thread, if a stock appearance is to be maintained, I think that you are stuck. (Some believe that damping the K600 helps. Some do not.) So: New Xovers New Tweeter (CT125 ?) Brace the Box Work on the room Regards,tc Quote Link to comment Share on other sites More sharing options...
BEC Posted December 31, 2007 Share Posted December 31, 2007 A bigger horn is the best thing that can be done for the midrange of the Cornwall in my opinion. That of course does include either mounting that horn outside the cabinet or at least cutting a much larger hole in the motorboard to mount a larger horn. If you don't want to do either of those things, you can try rolling off the midrange to about 4500 by a crossover mod. Then crossing to the tweeter (a different tweeter) at 4500. The original K-77 should not be used to do that because it is pretty delicate when it comes to low frequencies and needs to be crossed at around 6000. Bob Crites Quote Link to comment Share on other sites More sharing options...
HarryO Posted December 31, 2007 Share Posted December 31, 2007 "Zeno, Buddy, you are in luck, I have a set of Dean build modified type B network with VCaps." I'd love to see a couple of detailed pics of the B mods if available. I like the K-600 horn with K-55 or K-51 drivers. Properly driven they are a nice horn. Just make sure they're tight against the motorboard. With fresh caps and diaphrams they can be a very smooth lens. They're a bit picky with what you drive them with though. Harry Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 31, 2007 Author Share Posted December 31, 2007 Thanks Mark, I think I see it now. You are the problem solver. Here is yet another known technique and style for making substitutions in the Cornwalls without breaking any of the Klipsch rules: -uoieroiuer & gfhasdhgfa Modding the Cornwall: 1. Remove and throwout the tweeter, midrange, woofer, and crossover. 2. Holding the serial label carefully in place, peel the cabinet off the label and discard it. (Uh, the cabinet, not the label!) 3. Holding the label vertical, glue a new cabinet to it. One that can accept much bigger horns and woofers. 4. Get a series of Altec, JBL and Crites horns and drivers and mount carefully in the new cabinet. 5. Get a crossover from Al Klapenberger and mount in the new cabinet. Enjoy your modified Cornwalls! Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 31, 2007 Author Share Posted December 31, 2007 Ok, how about that idea of changing the tweeter and Xsing over at 4500. Does your tweeter fit the bill here Bob? So is it just above 4500 where the offending frequencies live? Crossing over at 4500 will anything feel missed or does the new tweet take care of it. Have people enjoyed this approach to a solution? What type of crossover mod is necessary here? -lxcnvb & euyruery Quote Link to comment Share on other sites More sharing options...
Clipped and Shorn Posted December 31, 2007 Author Share Posted December 31, 2007 "Zeno, Buddy, you are in luck, I have a set of Dean build modified type B network with VCaps." I'd love to see a couple of detailed pics of the B mods if available. I like the K-600 horn with K-55 or K-51 drivers. Properly driven they are a nice horn. Just make sure they're tight against the motorboard. With fresh caps and diaphrams they can be a very smooth lens. They're a bit picky with what you drive them with though. Harry Nice to see a vote for the stock horn and driver, I will know more when I audition the Dean Bees and the SET with Merlin. Who knows, maybe Dean's Bees will be the Bee's Knees, in which case I will stop there. Remember, I am not expecting the ultimate here. -@ & # Quote Link to comment Share on other sites More sharing options...
BEC Posted December 31, 2007 Share Posted December 31, 2007 Well, the theory is that the K-55V is really streched out trying to make it to 6000 hz. But it has to do that because of the tender K-77 tweeter. Several have done this mod in Khorns, Lascalas, and (fewer but some) Cornwalls. And yes, my tweeter likes it fine being crossed at 4500. The mod is a change of one capacitor value in the Type B crossover and addition of one inductor in the squawker circuit. That inductor gives a gentle roll off of the squawker at 4500 and the cap lowers the crossover frequency to to the tweeter to 4500 hz. I can't say you would like it or not, or, that it cures the problem you have with the midrange sound. I can say that most (perhaps all) who have tried this mod liked it. Bob Crites Quote Link to comment Share on other sites More sharing options...
fini Posted December 31, 2007 Share Posted December 31, 2007 Bob, What specifically would be the mod for the type AA/A in my Khorns (the ones you updated a while back)? Should I send both Khorns to you, or do you just need the bass bins? Quote Link to comment Share on other sites More sharing options...
BEC Posted December 31, 2007 Share Posted December 31, 2007 Fini, The mod for a type A is exactly the same as for a type B. Change the value of one cap and add one inductor. And, of course, add different tweeters. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted December 31, 2007 Share Posted December 31, 2007 "It would seem they were wound rather loose if cabinet vibration changes how tightly the winding is coupled to the core......you sure they just were not wound sloppy from the get go?" Most of the ones that I've handled with the windings sliding around on the core were from Type A's and AA's, so it's not from vibration. Maybe you're right, maybe they were that way from the beginning -- I suppose that's possible. Quote Link to comment Share on other sites More sharing options...
BEC Posted December 31, 2007 Share Posted December 31, 2007 It is pretty easy to see some differences in construction of the new autotransformers. The T2A on the left is lots smaller than the 3654 on the right as you can see in this picture. The T2A is wound on what is called a 3/4 inch stack and the newer replacement ones are all based on a 1 inch stack. Bob Crites Quote Link to comment Share on other sites More sharing options...
BEC Posted December 31, 2007 Share Posted December 31, 2007 Also notice the thick coating of lacquer on the 3654 from being dipped and allowed to soak for a long period of time to seal and fix the winding into position. Spacers are also added to each end of the coil to perfectly center the windings. Bob Quote Link to comment Share on other sites More sharing options...
sherwoodhifi Posted January 1, 2008 Share Posted January 1, 2008 I'd love to see a couple of detailed pics of the B mods if available. A picture of my xover. My mod Type B xover is really a CornScala xover with a 8 ohm JBL 2426H mid driver. To use it as Type B, just move the squawaker tap from 2 to 3. It has one extra coil to roll off the squawaker at around 6 Khz. to the BEC tweeter. Currently, I am running the CornScala as 2 way with active crossover. Panasonic XR55-> K33 woofer, type #45 SET tube -> ALK horn/JBL 2426H for mid/high. Quote Link to comment Share on other sites More sharing options...
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