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K77 Diaphragm replacement?


holtrp

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One of my K77 horns gave up on me.

Is there an easy way to tell if it is the diaphragm? And if it is the diaphragm, is it best to swap all of them out? I imagine it is sort of a wear and tear item that would benefit from being replaced. I swapped the entire K77 out with one on a Belle I am not currently using, so I am not in a hurry.

Crite has some good instructions and it looks simple enough to do on my own. Anyone have experience here that wants to jump in would be welcome. Ebay seems to have some good deals, but I don't know if these replacements are the same you would get from Crite.

Thanks

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An ohm meter will tell you if the diaphragm is open. I think Bob's (Crites) website will help with the diagnosis. A few years back Bob was trying get a vendor on board to make replacement diaphragms but was not happy with the quality. I don't know the status of this now. Perhaps Bob will chime in here.

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One of my K77 horns gave up on me.

Is there an easy way to tell if it is the diaphragm? And if it is the diaphragm, is it best to swap all of them out? I imagine it is sort of a wear and tear item that would benefit from being replaced. I swapped the entire K77 out with one on a Belle I am not currently using, so I am not in a hurry.

Crite has some good instructions and it looks simple enough to do on my own. Anyone have experience here that wants to jump in would be welcome. Ebay seems to have some good deals, but I don't know if these replacements are the same you would get from Crite.

Thanks

The K77 from your Belle is one of a matched pair and they are of the highest Quality that Klipsch had much better than found in Cornwall and Heresy. I would suggest that you keep your Belle parts together and intact.

You can replace both of your other K77 with a set of CT125 from Bob Crites they are an excellent tweeter better (in my estimation) then the stock K77 by a wide margin. Bob Is your go to guy. Hope this helps best regards Moray James.

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Moray, I'm always running into things written by you that I don't understand. please explain the difference between a K77 diaphragm found in a Heresy and Cornwall and those found in the big Heritage loudspeakers.

Bob has replacement diaphragms that are identical to current production. They are not capable of taking as much power as the ones with the beryllium leads found on the EV units. The K-77-M was used in all five loudspeakers.

I like the sound of the K-77, even though I know it's a dog. I like the Klipsch "house sound". The early roll off of the tweeter works especially well with the Heresy, LaScala, and Belle Klipsch, which have limited bass response. A balanced sound is preferred to an uneven distribution of acoustic energy. If I were going to upgrade the top section, there are better performing options. I very much want to hear the B&C DE120 available from Al. I have the waterfall plots for all of these drivers, and can't for the life of me can't figure out why Al doesn't post them on his site.

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Dean: I guess if the Khorn LaScala and Belle were race cars they would be stock cars. Parts selected by hand tested and matched in pairs. The Tweeters in the top three Klipsch were the best of the lot. Cornwall and Heresy got the left overs. I expect that they still select the best of inventory on those speakers and match pairs. You can check with Klipsch and check to see if you are interested. These days I expect the differential to be much smaller than in decades gone by.

I replaced my Heresy K77 with a set of Bob's CT125 and was delighted with the sound quality of that driver. Bob's ti diaphragms in a set of modified K79 drivers also makes for a very fine sounding tweeter. I have recently used a pair of EV D1506 and also DH1A's and I don't think I will be going back to any Klipsch tweeters again. The only driver I can think of that might better the DH1A is one of the Beyma drivers but the sticker price is way past what I have to invest. I could be happy with the DH1A for along time. At the end of the day with EQ the DH1A will provide the same high end and more bottom end though the Beyma might be a little cleaner I don't really know. Well there you go Dean hope that helps. Best regards Moray James.

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Dean: I guess if the Khorn LaScala and Belle were race cars they would be stock cars. Parts selected by hand tested and matched in pairs. The Tweeters in the top three Klipsch were the best of the lot. Cornwall and Heresy got the left overs.

really?

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All of the K-77 tweeters varied somewhat in output, and they were ALL matched in pairs. No speaker pair got a mismatched pair, the discontinuity in imaging (and sensitivity) would have been horrendous. However, I think I can accept that the big three would have received the most efficient pairs ...

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"really?"

A nice story (if true).

Well I figured that I should check the story out. I contacted Roy who referred me to Jim Hunter and here is Jim's reply.

Jim Hunter

To Roy DelgadoMe
Today at 11:37 AM

The K-77 tweeter was adopted in 1957. In the early years of production the level varied several dB. Paul graded these into high, nominal, and low, and had three different Klipschorn network “versions” to accommodate them. A few years into production the consistency improved significantly, and the practice was dropped. Not sure, but probably by 1960. I do not have evidence of sorting for Heresy and Cornwall. Note that the LaScala started in 1963 and the Belle in 1971.

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Is this why we have three different K500/5000 crossovers?

The Heresy went into production in '57 and the Cornwall in '59. If they stopped doing this in '60, it sure didn't last long.

Looks like Moray was for the most part correct,

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"Looks like Moray was for the most part correct,"

Only in the context of the very small quantity of drivers used prior to about 1960. Klipsch used more tweeters in any one month in the late 70's than they did in all of those early years.

EV had such a problem with diaphragms that they started internal selection prior to installation in a complete driver. The best diaphragms ended up in the T350, then the T35, then the Michigan, Wolverine, and all the other bottom-of-the-barrel models.

Edited by djk
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"Looks like Moray was for the most part correct,"

Only in the context of the very small quantity of drivers used prior to about 1960. Klipsch used more tweeters in any one month in the late 70's than they did in all of those early years.

EV had such a problem with diaphragms that they started internal selection prior to installation in a complete driver. The best diaphragms ended up in the T350, then the T35, then the Michigan, Wolverine, and all the other bottom-of-the-barrel models.

Yes but that early time was what I was referring to. My fault was that I thought the selecting of tweeters had carried on up till the time of the Belle.

Here is what Bob Crites had to say about it, see below.

"I think they always had to match up the K-77 tweeters used in the Heritage series. That was because the output varied so much between tweeters.

The ones they use now, the K-77F, are purchased with a requirement that the tweeters all match to within 1 db, so they likely do not have to do that now. I think that tweeters first use was in around 2004.
Of course all the speakers that come off the line at Hope have an FR test run on them, so they would catch an out of spec driver anyway.
Thanks,
Bob Crites
Perhaps we may hear more form some of the guys who were on the floor at Klipsch back then there are a few lurking about still I think. Always interesting to find out about these kind of things. I enjoyed the factory tour video as well worth the time. So who did the engineering on the Forte ll the Chorus ll and the Quartet. Was that Roy? Gary Gillum did the Forte and Chorus according to the QC manager in the Factory tour video. Best regards Moray James.
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I may be new around here although I am keen on facts that I have found and studied to keep as fact with the legend and what happened within and around especially the early times as that is when it all began. That said Moray...You are indeed 100% accurate and I do know how and where to back you up with those facts. Those facts and the k77, t35 klipsch history is/are actually mostly/partially stored within the archives of the klipsch forum and could not have been more accurately described than you have done all so within this very thread...Once again a great example to be up to date with facts of the legend in sound.

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