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K-77 Tweeter Replacement Driver while keeping the lens/horn

Lost Cause

Lost Cause

New Member
After having fun making some DIY Cornwalls and Heresys, I wound up with some extra K-77 tweeters that aren't working (even after replacing the diaphragms).

I know that there are a number of K-77 drop-in replacement tweeters (e.g. those offered by Crites). For example, the B&C DE120. But they seem to be offered with a new horn/lens.

So, I am wondering if there are any drivers that can be simply screwed into the K-77 lens/horn. For example, does the B&C DE120 fit the K-77's four-bolt pattern? Any other (cheaper) alternatives that can simply be bolted on?

Thanks in advance!
 
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soundbound said:
If you put in new correct diaphragms correctly they should be operating correctly.
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Well, for one of the tweeters, the magnet has separated from the housing (the housing itself is dented, so it probably was dropped at some point). I know it can be epoxied, but am deciding whether its worth the hassle. And for the other one, I believe the magnet has become de-magnetized (based on feedback in a past thread).

Setting aside whether the drivers can be fixed, I'm asking whether any replacement tweeters bolt into the K-77's horn/lens.
 
Lost Cause said:
Well, for one of the tweeters, the magnet has separated from the housing (the housing itself is dented, so it probably was dropped at some point). I know it can be epoxied, but am deciding whether its worth the hassle. And for the other one, I believe the magnet has become de-magnetized (based on feedback in a past thread).

Setting aside whether the drivers can be fixed, I'm asking whether any replacement tweeters bolt into the K-77's horn/lens.
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Dang... That’s not good. Ask over at the forums at Klipsch.com, they may have an answer for you and maybe Parts Express can advise you, because they sell lots of drivers and horns.
 
Most if not all drivers available for that horn are round and are too large to fit in the cabinet. You will need a square one like the ones Crites sells if you want it to fit inside your cabinet. Bob Crites criticized the simplespeakers diaphragms as not up to par but there are many they use and enjoy them. I am leary sellers criticizing their competitors products. Installed correctly they should work. The above post may be the ticket as well.
 
@Lost Cause I’ve heard nothing but negative reports about all the diaphragms made for k-77. I was going to purchase them from crites but $90 for diaphragms is crazy. Rumor is his are made in China just like everybody else’s. You might have a magnet issue, I’ve been reading up on people needing to remagnatize their k77 round magnet. I’m going to give Dave’s mahl and de-10 a go in my chorus ii and if I love them I’ll probably do the same in my Cornwalls. If you’re dead set on staying with k77 I’d recommed placing a wtb add on the Klipsch garage sell forum, they’re for sale on there pretty often and I’m sure guys have some laying around after going with crites or mahls.
 
Good morning, I 've been down this road before. I have a set of Crites in my Heresy's & now in my Cornwall's (FULL LENS). The Part express diaphragms in my Chorus ll. Dave's Mahl tweeter's sitting on top of my LaScala's ll w/dc 20 driver & Altec's 511 horn. I listen to all venues of music, & sometimes @ concert levels & none of them let me down. Now the best tweeter I have, are the JBL Baby Cheeks in which I now use on top of my Corns. w/ Altec 511 horn & K55v driver. I'd love to find a set of Altec's 311/90 horns, but haven't found any as of yet.
 
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wdecho said:
Most if not all drivers available for that horn are round and are too large to fit in the cabinet. You will need a square one like the ones Crites sells if you want it to fit inside your cabinet.
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I don't understand your point on this. The K-77 drivers came in both round and square (with the square being introduced later, I believe), and fit in Heresy cabinets easily (and more easily in Cornwall cabinets). In fact, the CT120's are round.
 
Madman1 said:
@Lost Cause If you’re dead set on staying with k77 I’d recommed placing a wtb add on the Klipsch garage sell forum, they’re for sale on there pretty often and I’m sure guys have some laying around after going with crites or mahls.
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Thanks, seems there really isn't any replacement driver that bolts into the K-77 lens, people just replace both the lens and the driver together.
 
Lost Cause said:
I don't understand your point on this. The K-77 drivers came in both round and square (with the square being introduced later, I believe), and fit in Heresy cabinets easily (and more easily in Cornwall cabinets). In fact, the CT120's are round.
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I was referring to my LaScala's. Too small a spot that the tweeter sits in for anything but the small square K-77. Never seen round magnets on a K-77 but I am sure you are right. Personally I say just buy baby cheek horn and attach Selenium D220-TI put it in a wood slide on top of the cabinet. Wonderful sounding.
 
I'm rejuvenating this post since I'm in the process of upgrading the tweeters in my Fortes.

As is well known, aftermarket horns and most drivers will not fit in the small space afforded for the K77 in this enclosure. After searching through the various 1" drivers on the market, looking at magnet diameter and mounting, the B&C DE120 still seems to be the best. However, my order at Parts Express was back-ordered many weeks, suggesting that their availability is becoming limited. The cost of the aluminum horn flare fabricated by Dave Ault is out of my budget and machined aluminum, while a masterpiece, seems like overkill in the era of 3D printing.

I found that the oem K77 horn will fit on the DE120 driver with slight modification that allows for re-using the original horn, i.e., filing the flange in two places to accept two 5mm screws that mount securely it to the DE120 magnet. The subjective sound difference is subtle but offers a bit more detail and crispness.

I do have a question regarding the K77 horn: what is the purpose of the cone centered above the opening of the driver, as highlighted in the attached photo? All of the horns on the market lack this feature. Will its removal improve the sound? Alas, I do not have the equipment to measure acoustic properties, so rely on experts for this information. Thanks!
 

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jdkinase said:
I found that the oem K77 horn will fit on the DE120 driver with slight modification that allows for re-using the original horn, i.e., filing the flange in two places to accept two 5mm screws that mount securely it to the DE120 magnet. The subjective sound difference is subtle but offers a bit more detail and crispness.

I do have a question regarding the K77 horn: what is the purpose of the cone centered above the opening of the driver, as highlighted in the attached photo? All of the horns on the market lack this feature. Will its removal improve the soun
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That's a Phase Plug. It was designed in conjunction with the driver to improve the dispersion and they typically tend to be driver specific.
 
Gigantic said:
That's a Phase Plug. It was designed in conjunction with the driver to improve the dispersion and they typically tend to be driver specific.
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That’s also not a k-77 horn….

That’s the front mounted exponential horn used in H2, forte, quartet, chorus and a plethora other 80-90’s klipsch…

And yes, you’ll need to dremel out the phase plug if using the de10 or de120 on that horn. They have a phase plug integral to the driver
 
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winglet said:
That’s also not a k-77 horn….

That’s the front mounted exponential horn used in H2, forte, quartet, chorus and a plethora other 80-90’s klipsch…

And yes, you’ll need to dremel out the phase plug if using the de10 or de120 in that horn. They have a phase plug integral to the driver
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I've been playing with my brother's Chorus II's. The DE10 is too big to fit through the front. The DE120 will but they are hard to get. I'd use the much smaller Celestion cdx1-1412. The only other issue you may want to consider is the tweeter sensitivity. The tweeter you have is around 100db vs the 106-107db of the newer drivers.
 
@jdkinase The stock Forte I tweeter is the K-75-K....not a K-77. Totally different. There are differences between most all the "plastic" tweeters...K-74, K-75, K-76, K-79, etc., mainly in efficiency and magnet size I believe.
 
Got it! Thanks for the input! I should have added that I'd already upgraded to the Crites Ti on the K75s and re-capped the crossovers.
 
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