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Hersey tweeter replacement and infomation


Pirate

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Hi All, I'm a newbie and just discovered this site. I have a set of Heresy's that I bought new in 1977 and they have in storage for  years. One of the tweeters isn't working so not sure if it's the diaphragm or the crossover and I haven't had a chance to put a meter on them. The serial# are 25P006/7, not sure what series these are but the tweeters are K-77, serial # 51685 on the non-working one. Reading an old forum here about the same subject and people replied with upgrade suggestions and sources. Any information would be greatly appreciated, thanks in advance, Peter.

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I would not bother with an "upgrade" at this point.

 

First, go ahead and get the voltmeter out to see if the tweeter is reading "open" or not, and then check the connections to and from the crossover (if necessary, swap with the crossover section from the working side)

 

If there actually is a problem with the tweeter, then go ahead and fix, replace, or upgrade. Keep in mind that is best to do both sides at the same time.

 

Upgrading a working K-77 has never made much sense to me. However, there are plenty of competent people who would not agree.

 

Good luck,

-Tom

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37 minutes ago, mustang_flht said:

Welcome

 

Yes I confirm ask Bob Crites what he has as a solution for you: either a diaphragm for K77 or a CT125 which will repair your beautiful Heresy

 

😄

Bonjour @mustang_flht,   ,   off beat question    anyway you can check in France    , if you can purchase the Celestion CDX07-1075 , here is North America it is OEM only , so my guess is only for bulk manufacturers -tx

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Of course I agree with Preston Tom.  

 

If you don't have a multimeter, you need one.  If you don't know how to use there is a lot of how-to s on YouTube.

 

Generally, at the tweeter teminals you should get a reading of 10 ohms or so if it is good and you'll hear some scratching noise from the tweeter as you apply the probes.  If it is "open" meaning  burned out you'll get a reading of infinite ohms.   (Maybe  OL.)   Whatever you get when the meter is set to ohms and the probes are not touching.  

 

In theory you don't even have to disconned the wires.

 

One good move is to back off the screws on the cross over about one half turn and then snug them down.

 

The tweeter is the driver of the three which is the most delicate and will take 2 to 5 watts continuous.  Failures are common.

 

Check if Bob C will replace the diaphragm for you by mail.

 

WMcD

 

 

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