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1978 alnico K77 tweeter rebuilt


seti

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I sent my 78 alnico tweeters to Bob & Michael Crites late last week and got them back in the mail this morning. That is what I call fast service. They got new diaphrams new hook up wire and one of them was even bent when they arrived but not after Crites fixed it. I put them back in the Khorns this afternoon and played a couple albums. It is nice to have the tinkle of cymbals back again. With vintage gear it is always refreshing when they get an overhaul. Next I'l replace the diaphrams in the K-55 and perhaps give those cast frame woofers a run.

Thanks again Bob & Michael... Top notch.

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Crimeny Crites. Why would you replace K55 diaframs unless they were blown? Crusty critter wants to know.

Ah!! There is a question I should answer. First of all I have no idea if Seti needs his K-55V diaphragms replaced or not. But, I can tell you of 4 (but who is counting) cases where I have found K-55V diaphragms to be bad but still working. The first instance of this involved a good upstanding forum member (reported as having great hearing) who sold me a pair of K-55Vs. He told me they were working great in his Khorns and that he was just selling them after getting a pair of the dual phase plug K-55Vs. Well, when I got them, I decided to test them and found that neither of them had any real output below 1 khz.

I replaced those diaphragms and then the output of both tested good.

This told me two things.

1. A K -55V diaphragm can be bad and still work.

2. Self professed audiophiles may not have very good hearing.

Since that time, I have found two more K-55Vs with exactly the same symtoms that were also fixed by replacing the diaphragms. Those two were Ebay buys, so don't have any history on those.

I really don't know how common that problem is. Can the average audio nut tell if his speakers are not putting out any frequencies between 400 and 1000 hz?

Bob Crites

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The Klipschorns I picked up spent some time with the elements. Perhaps a garage or carport. I found at least 100 dead spiders with multiple nests and 10 mud dauber nest all around the K400s. In places the veneer is slightly lifting as well. This being the case just to be on the safe side I am replacing diaphrams on my tweeters and midrange horns. It could be possible that they are ok but I want to make sure they are tip top. It is not like I am dumping a boatload of money on these. I'll also likely give those cast frame woofers a spin as welll. I'm really happy to have khorns but just want to make sure they are as fresh as can be. If this is a form of nervosa than I got it : )

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I replaced the diaphrams in my '76 CWs a couple of years ago and the difference was night vs. day. Mine still worked but I figured after 30 years they had to be worn out or dried out. I'm glad I "freshened up" mine. Sounds a bunch better.

Harry

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Krickey Crites! A confabulation of crenelated confusion confounds my cranium.

My whole world speakerwise has collapsed. The Forum Bible states in no uncertain terms: "Refreshith thy caps and thine speakers will sing like the angels without further labor until the coming of the Resurrection". Now I'm given to learn that entropy rules throughout the realm of Earth and Klipsch. Worse yet, how can I tithe the Church of Tubes it's 10 percent of hard-earned lucre if I must re-direct funds to appeasing the K55.

100omhz you say? Do I really need 1000mhz? Can I get along without it?

My corpulace is troubled.

Crapola.

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Krickey Crites! A confabulation of crenelated confusion confounds my cranium.

My whole world speakerwise has collapsed. The Forum Bible states in no uncertain terms: "Refreshith thy caps and thine speakers will sing like the angels without further labor until the coming of the Resurrection". Now I'm given to learn that entropy rules throughout the realm of Earth and Klipsch. Worse yet, how can I tithe the Church of Tubes it's 10 percent of hard-earned lucre if I must re-direct funds to appeasing the K55.

100omhz you say? Do I really need 1000mhz? Can I get along without it?

My corpulace is troubled.

Crapola.



Zonkers Thebius Maximus what are you on about? Take a couple sips of some fine california wine and let it mellow. The forum bible is subject to retranslation and interpratation. I burned mine and now try everything for myself. Except for those shitara stones that chap is on about.

Seriously my speakers were exposed to the elements long enough for spiders and wasps to make their home in the khorns. I can't even read my Klipsch labels they are so weathered.

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Seriously my speakers were exposed to the elements long enough for spiders and wasps to make their home in the khorns. I can't even read my Klipsch labels they are so weathered

Who does that with their speakers?

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Crimeny Crites. Why would you replace K55 diaframs unless they were blown? Crusty critter wants to know.

Ah!! There is a question I should answer. First of all I have no idea if Seti needs his K-55V diaphragms replaced or not. But, I can tell you of 4 (but who is counting) cases where I have found K-55V diaphragms to be bad but still working. The first instance of this involved a good upstanding forum member (reported as having great hearing) who sold me a pair of K-55Vs. He told me they were working great in his Khorns and that he was just selling them after getting a pair of the dual phase plug K-55Vs. Well, when I got them, I decided to test them and found that neither of them had any real output below 1 khz.

I replaced those diaphragms and then the output of both tested good.

This told me two things.

1. A K -55V diaphragm can be bad and still work.

2. Self professed audiophiles may not have very good hearing.

Since that time, I have found two more K-55Vs with exactly the same symtoms that were also fixed by replacing the diaphragms. Those two were Ebay buys, so don't have any history on those.

I really don't know how common that problem is. Can the average audio nut tell if his speakers are not putting out any frequencies between 400 and 1000 hz?

Bob Crites

Bob, would it work for me to use my 1/3-octave analyzer to test K400/K-55 output by unhooking the woofer and tweeter from the crossover? Should I see a relatively flat line from 400Hz - 6000Hz? Would I notice enough of a drop off between 400Hz and 1000Hz to know if the diaphragms needed replacing? Is it harder or easier to replace K55 diaphragms compared to K77's?

Can we hear it? I suspect it depends on how far the frequencies have dropped off. 3db - probably most people would not notice, but 10db - I'd like to think I would notice that.

Greg

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If they are as bad as the 4 that I mentioned above, I think I could hear it. Seems to me that I measured some frequencies below 1 khz at least down 10 db.

I would rate changing the diaphragms on a K-55 to be easier than a K-77. Just more expensive. I keep meaning to do a tutorial on changing those with some pictures. Just can't remember to do that when I have one to change. Now that I am thinking of it, I do have one to rebuild this weekend. Might do the pictures.

Bob Crites

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Guest " "

I have a set of k-55's I am using and was going to look into replacing the diaphragms in them becuase they did not sound right. I took the drivers a part and found things in a general state of crud. I cleaned everything out with brake fluid, wiped dry, and reassembled. The sound inproved enough where I decided not to replace the diaphragms. The brake fluid thing has been around for a few years on various forums. One of the few fluids that will not break down the glue used to hold the voice coil former to the diaphragm. Water based fluids will cause corrosion.

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