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Zener Tweeter protection


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44 minutes ago, jason str said:

Ah yes, Alligator clips.

I guess you could burn those tweeters out if you really tried but don't think it's needed here.

 

OK, the JBL Le25 tweeters are rated at 20 w RMS and 40  peak.  Should be OK.

 

I cannot find a specification for the Klipsch K79s. Does anyone here know?  Are they 5 watts or quite a but higher? 

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15 minutes ago, tigerwoodKhorns said:

 

OK, the JBL Le25 tweeters are rated at 20 w RMS and 40  peak.  Should be OK.

 

I cannot find a specification for the Klipsch K79s. Does anyone here know?  Are they 5 watts or quite a but higher? 

Power ratings are based on a set frequency and crossover slope, without knowing more information cannot really help. 

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49 minutes ago, Curious_George said:

STR - You are showing your age! I love it. He said roach...

 

Back in the day we always used roach clips because a high roach is easier to deal with than a high alligator, and if they go to sleep the roach is easier to move.

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30 minutes ago, tigerwoodKhorns said:

OK, but JBL publishes specs for their tweeters. 

Can't find anything, how are you using these ?

30 minutes ago, tigerwoodKhorns said:

 

The K79s are crossed at 5000 and 7000 and the crossovers both look like third order so 18 db slope. 

Klipsch does not publish K79 anything.

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  • 4 weeks later...
23 minutes ago, Limberpine said:

What's the best way for me to disconnect the zenner diode from my AA networks. I took the red side off and it stopped the tweeter from working. 

 

Should I just clip on of the zenner wires? 

 

Here are some pics of what I'm looking at.

20220228_151511.jpg

Just remove them from the metal mounting plate, wrap in some electrical tape. Do not let them touch anything or each other.

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24 minutes ago, babadono said:

Just remove them from the metal mounting plate, wrap in some electrical tape. Do not let them touch anything or each other.

So the zener wire is soldered together with the tweeter spades. I took the positive side off, by unscrewing the screw from the terminal block and taping the spade  so it doesn’t touch anything and the tweeter didn’t produce any sound. 

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48 minutes ago, Limberpine said:

What's the best way for me to disconnect the zenner diode from my AA networks. I took the red side off and it stopped the tweeter from working. 

 

Should I just clip on of the zenner wires? 

 

Here are some pics of what I'm looking at.

20220228_151511.jpg

 

The easiest way to remove the tweeters from the circuit is remove one diode from bracket, I believe it's a 3/8" nut. Once one diode is removed from the metal bracket insulate it with anything, I use heat shrink tube. Make sure it's covered well and then zip tie it to the bracket or a wire, anything to hold it stationary while it's out of circuit and "floating". You can remove both diodes but it's not necessary.

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And hopefully you are doing this with no input to the speaker. Those tweeters are fragile. Usually back in the day they got blown out  on an impulse, like someone dropping the needle onto a record. With the volume up too high.

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16 minutes ago, Limberpine said:

I took the positive side off, by unscrewing the screw from the terminal block and taping the spade  so it doesn’t touch anything and the tweeter didn’t produce any sound. 

 

If you look there are two wires crimped to that spade on the terminal, if you remove it you lose your tweeter.

 

The best way is just remove one diode from the metal bracket and insulate it as I explained above. The nut holding the zener on I believe is 3/8". You can wrap in electrical tape, I choose not to because if I want to use it again it all sticky from the tape adhesive. If you're going to tape it put some paper or plastic wrap around the diode before taping.

 

I may just remove all 4 and sell them in the future, if nobody has checked those things are going for big bucks.

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3 minutes ago, babadono said:

Re. The price of metal stud power zeners......yes its nuts!

 

 

It's crazy. The 1N3996 is going for $38 each ouch

 

https://www.mouser.com/ProductDetail/Microchip-Technology/1N3996?qs=%2BRKXB2WKlSeuDut61y4Atw%3D%3D

 

You could probably list all 4 for $60 and get it, that's $15 a pop. I suppose people leave them in case they sell the speakers and someone wants them stock with the protection circuit.

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