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WTB K77M Tweeter (NO LONGER NEEDED)


Youthman

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Update: No Longer Needed

 

Last night I ran Dirac Live on the Monolith HTP-1 and discovered one of the tweeters in my 1980 LaScalas is not working properly.

I need to test it to see if it's working at all but wanted to see if anyone has one for sale.

Thanks,

Michael

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1 hour ago, Youthman said:

If I replace the diaphragm from Bob would it still sound the same as the other two tweeters?

HI  @Youthman  , there were several diaphragms on the K77 -------and they are not all the same ,some had Beryllium leads  , some do not   -the ones sold at Crites are the cups  for the latest K77F  made in Asia , but still used on the AL5 -----there is no soldering requirement , you unscrew the magnet -  pop the cup off , replace a new cup -6 to 6.2 ohms DCR

 

----- I have a few that read a full  8ohms   -------the latest ones  are closer to 6 ohms -

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I bought a replacement diaphram on eBay and fixed my K-77M no problem.  Doesn't sound any different than the other one.  Simply Speakers in FL must have diaphrams for those you don't need a whole new tweeter body just replace the diaphram.  You will need some soldering skills though but it is pretty easy.

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These old ears could not distinguish between Alnico or ferrite (mud) T35/K77s, but, perhaps the Alnico magnets needed to be remagnetized.  Similarly, I doubt I could tell the difference between the sound of replacement diaphragms from Crites or Simply Speakers.  Nonetheless, I trust Bob Crites when he says he tested the aftermarket diaphragms and found them wanting.  If I’m investing time and money in a DIY repair, I want a part that meets Bob’s criteria.  I would also want a pair of “matching” tweeters, whatever the final selection.

 

It’s somewhat analogous to PWK’s selection of EV T35s to be re-branded as K77s. I seriously doubt if mere mortals could have noticed a difference, but PWK’s standards were different (higher?) than EV’s.  Of course, EV did not throw out PWK’s rejects, but sold them to other manufacturers or hobbyists.

 

FWIW, these old ears can perceive a difference between the T35/K77 variants and CT120 (DE120) tweeters.  That’s why the T35/K77s, whatever variant, are gone.

 

 

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The pair of 77's in my 81 LS were both toast so got a pair of Bob's 120's.  Sound great.  Speakers are fun.  They really don't eat much, it's just that first bite.  Order a couple and get that long phillip's screwdriver out.  You'll like til you light them up then they just squeak.  lol  :)

 

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15 hours ago, Youthman said:

Would the K77 and K77M sound different?

no , same tweeter - all square magnet k77 sound the same   ---the available diaphragms are aftermarkets    or aftermarkets pre-soldered on a cup  -------made in the PH  -China ----  

 

-I bought a pair of NOS EV  T-35 tweeters to avoid  the lower quality aftermarket diaphragms  , and I also have some Crites CT 125 as spares for the EV T35 --

 

-I prefer the EVT35 -K77 with  the original diaphragm   -------

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Well, I swapped the tweeters with my Left and Right LaScalas and took some measurements with REW and the issue stayed with the left cabinet so that means the tweeter is not the issue.

I'm wondering if the crossover is the issue. I'll update this thread and post in the Technical / Modifications section to see if I can get some additional eyes looking at my issue to help me troubleshoot it.

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On 8/25/2020 at 10:28 PM, Youthman said:

Well, I swapped the tweeters with my Left and Right LaScalas and took some measurements with REW and the issue stayed with the left cabinet so that means the tweeter is not the issue.

I'm wondering if the crossover is the issue. I'll update this thread and post in the Technical / Modifications section to see if I can get some additional eyes looking at my issue to help me troubleshoot it.

My money is on just a bad connection somewhere. Check connections on system and crossover. Clean with deoxit or something similar. Doubtful bad solder joint on crossover but possible. 

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