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Blew my La Scala II tweeters - how big of a deal?


JFHSQT
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I returned from Thanksgiving travel tonight and long story short, when rebooting my Mac Mini I sent a huge burst of bitstream noise into my 6 month old La Scala IIs ... to make matters worse, I had neglected to check the volume knob on the amp... assuming as I was reconnecting everything, it brushed against my shirt and was turned to 12 o'clock. 

 

So that digital burst must have been about 125 dB. I turned it down as fast as I could, but when I finally got the Mac Mini and Roon set up and went to play music, the top end sounds like it's very lo-res, cardboard... muffled and coming out of a box. 

 

So I'm about 98% sure I blew the tweeters in both La Scala IIs. They both sound the same. I plugged my RP-150Ms into the amp and they sound fine, so it's definitely the LS II components. Not sure if the crossovers were affected but for sure the tweets.

 

How much hassle is this going to be to track down and replace? Should I call Klipsch and try to order new tweeters? I assume this will not be covered under warranty. I just don't want to send these monsters off somewhere, and I'm sure the local dealer I bought them from will keep them for weeks and charge labor, etc. 

 

Can I get the same LS II tweeters from Klipsch? Should I take this opportunity to see if there's any tweeter upgrade I may want to do that would be an improvement over the most recent LS II tweeters?

 

Thanks for any advice. 

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Easy to diagnose. You need a voltmeter.

 

Set it to ohms/resistance. Disconnect the wires from the crossover to the tweeter (first pay attention to which wire goes to which terminal so you reconnect them correctly), and put your meter leads on the each wire- alligator clip leads help here. You should read a low resistance; less than say, 10 ohms. If the meter doesn't read anything, the voicecoil is open and the tweeter is bad.

 

To check the crossover, set the voltmeter to AC Volts. Clip those alligator leads on to the screw terminals you removed the wires from. Turn the volume all the way down, and play something over the speakers. You should read 0 Volts or close to it. Now, increase the volume and watch the readout of the voltmeter. As you increase the volume, the readout should go up. It will bounce around due to variations in the music, so if you can play interstation FM hiss it will be easier for you to observe. If you're not familiar with this it will look cool that you can actually change the reading by turning the volume knob! It will also confirm the crossover is fine. If the reading doesn't respond to varying the volume control, your crossover is bad.

 

Report back with your findings, if any.

 

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If, as you suspect, you blew the tweetets, only the diaphragms i n the tweeters would need to be replaced. They should be available from Klipsch.

 

Correct diaphragms can also ne puchased from Bob Crites at critesspeakers.com

 

Bruce

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  For 300.00 and some change you can install B&C DE-120 drivers and MAHL horns. They come with wires and connectors installed. Should be smoother sounding and may have survived your test. Better sound and better power handling. 

  Just a set of diaphragms are cheap. Could be warranty item. But getting them in for check out and repair would be expensive. They would want the speakers and not the drivers. 

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I had a brainfart a couple of months ago after installing a new Sherbourn amp and I put the XLR out from my CD player directly into the amp instead of into the preamp, then on to thee preamp. Well, that scared the absolute sh*t out of me. Came on blaring at 100% of the 200 watts per channel into my garage bound Infinity SM150's. After a quick flip of the power button and a quick peek behind the stereo I thought maybe the volume of the preamp was cranked, so I turned it way down....then turned the power back on AGAIN! Same exact instant mind blowing concert in my ears with me scrambling to turn it back off again. After that I found my mistake and corrected it. No harm no foul.

 

I will never for the life of me figure out why after 70 years that Klipsch has not figured out tweeter protection. I have 1988 purchased Infinity SM150 that have it. I had early 80's Technics SB-x500 speakers that had it. How many people blow woofers?....not many. How many people blow mids?....not many...yet I see this constantly, blown tweeters. On $7000 speakers it should be a no brainer to include it. Sad, but I hope you get them fixed.

 

 

Tim

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16 minutes ago, teaman said:

I had a brainfart a couple of months ago after installing a new Sherbourn amp and I put the XLR out from my CD player directly into the amp instead of into the preamp, then on to thee preamp. Well, that scared the absolute sh*t out of me. Came on blaring at 100% of the 200 watts per channel into my garage bound Infinity SM150's. After a quick flip of the power button and a quick peek behind the stereo I thought maybe the volume of the preamp was cranked, so I turned it way down....then turned the power back on AGAIN! Same exact instant mind blowing concert in my ears with me scrambling to turn it back off again. After that I found my mistake and corrected it. No harm no foul.

 

I will never for the life of me figure out why after 70 years that Klipsch has not figured out tweeter protection. I have 1988 purchased Infinity SM150 that have it. I had early 80's Technics SB-x500 speakers that had it. How many people blow woofers?....not many. How many people blow mids?....not many...yet I see this constantly, blown tweeters. On $7000 speakers it should be a no brainer to include it. Sad, but I hope you get them fixed.

 

 

Tim

My first pair floor standing speakers were SM150's that I bought at the base exchange on Minot AFB. I haven't thought about them in many years, thanks for sharing the story about yours.

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thYou should think about removing the tweeters from the speaker box to ship them, alone, for repair.

 

In that case, it might be dangerous to the amp to run the units with the tweeter removed unless you substitute a 10 ohm resister (or close to it).  This is because the network may form a short circuit at certain frequencies without a resistive load.

 

WMcD

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If your sure its the tweeter call Klipsch tell them what happened and ask if you can have a rebuild kit ? For a K-77-D  1'' tweeter. I mean you bought a very exspensive speaker the least they could do is give you new tweeters. 

They would not help a friend of mine on a sub amp I was a little pissed about that after I recommended him to buy Klipsch for their excellent service. 

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Test the specific drivers using a cardboard tube, Play the speakers take said tube (one from a paper towel roll works great) hold it up to each driver you will instantly know which driver is playing or not. Then its just a matter of ordering the correct diaphragm for the blown driver / drivers

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8 hours ago, teaman said:

I will never for the life of me figure out why after 70 years that Klipsch has not figured out tweeter protection. 

There is a polyswitch in parallel with a 100 ohm resistor. I’m surprised this combination didn’t save the diaphragms. 

 

I would physically inspect the networks. 

 

I would just call Bob. Klipsch isn’t going to send new tweeters, and will probably just send you to simplyspeakers for the diaphragms. 

 

You could change tweeters, but keep in mind that there is probably an LCR or two in the network to adjust the tweeter’s response - which will effect the new driver. OTOH, the room may have more of an effect than the response correction. 

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Thanks for all the great advice, it's been very helpful.

 

A couple of things...

 

I haven't opened the cabinet and done any testing with voltmeters, etc...

 

But I did the "cardboard tube" test, and it does appear that it's actually only the RIGHT tweeter that is blown. This would explain why I was able to hear the cymbals, etc in a recording like Chick Corea Trio's "Trilogy" but the recording still overall sounded muffled and lo-fi. 

 

One big fear I have is that I have never opened a speaker before, I am not really electronically inclined. I'm sure I can unscrew tweeters and horns and replace them, but things like inspecting networks, etc is totally greek to me. Dean, what you are saying makes sense but I have no clue how I would go about inspecting crossovers, networks, etc. If I just swapped out both tweeters would this still be necessary?

 

So I am thinking the easiest (not the cheapest) thing to do would be would be to simply order new K-77 tweeters and unscrew the old ones and screw in the new ones and plug them in, correct?

 

Then a possible "upgrade" option would be to call Crites and order a pair of new CT-120s, which would provide (according to reviews I've read) a smoother high end than the stock K-77.

 

What is the difference between the CT-120s and the B&C DE 120s on Parts Express?

 

Also, the final BIG question - I cannot see how in the world the top cabinet comes apart to access the tweeters. It looks like a big molded veneer box, even the front grill seems to be built into the box. Is this a simple job that I am missing somehow? Can I do this myself with a screwdriver in my living room?

 

The last thing I want to do is get a service center involved where I have to move these or wait for weeks for repairs.

 

In the meantime I've put my RP-150Ms on top of the LS IIs and I'm using them instead along with my SB-16 Ultra. I wish I could say "Wow, there really isn't THAT much of a difference between the RP-150Ms and the La Scala IIs!" Hahahaha! But that is not the case :(

 

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Quote

In the meantime I've put my RP-150Ms on top of the LS IIs and I'm using them instead along with my SB-16 Ultra. I wish I could say "Wow, there really isn't THAT much of a difference between the RP-150Ms and the La Scala IIs!" Hahahaha! But that is not the case :(

 

 

No, you really don't wish you could say that.............

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36 minutes ago, JFHSQT said:

Thanks for all the great advice, it's been very helpful.

 

A couple of things...

 

I haven't opened the cabinet and done any testing with voltmeters, etc...

 

But I did the "cardboard tube" test, and it does appear that it's actually only the RIGHT tweeter that is blown. This would explain why I was able to hear the cymbals, etc in a recording like Chick Corea Trio's "Trilogy" but the recording still overall sounded muffled and lo-fi. 

 

One big fear I have is that I have never opened a speaker before, I am not really electronically inclined. I'm sure I can unscrew tweeters and horns and replace them, but things like inspecting networks, etc is totally greek to me. Dean, what you are saying makes sense but I have no clue how I would go about inspecting crossovers, networks, etc. If I just swapped out both tweeters would this still be necessary?

 

So I am thinking the easiest (not the cheapest) thing to do would be would be to simply order new K-77 tweeters and unscrew the old ones and screw in the new ones and plug them in, correct?

 

Then a possible "upgrade" option would be to call Crites and order a pair of new CT-120s, which would provide (according to reviews I've read) a smoother high end than the stock K-77.

 

What is the difference between the CT-120s and the B&C DE 120s on Parts Express?

 

Also, the final BIG question - I cannot see how in the world the top cabinet comes apart to access the tweeters. It looks like a big molded veneer box, even the front grill seems to be built into the box. Is this a simple job that I am missing somehow? Can I do this myself with a screwdriver in my living room?

 

The last thing I want to do is get a service center involved where I have to move these or wait for weeks for repairs.

 

In the meantime I've put my RP-150Ms on top of the LS IIs and I'm using them instead along with my SB-16 Ultra. I wish I could say "Wow, there really isn't THAT much of a difference between the RP-150Ms and the La Scala IIs!" Hahahaha! But that is not the case :(

 

Hi, I'm in the same boat as you, I blew my right tweeter last week. ATM I'm waiting for my replacement to arrive.

I can walk ya threw the disassembly of the top-hat.

First remove the grill , I used a butter knife slipped between the grill and faceplate frame and gently pried it out. Theres 4 lil magnets holding it.

Once the grill is off you can see 4 screwheads (what the lil magnets hold onto) remove these and the faceplate comes off. Now you can see all the motor-board screws, leave them for now.

Next flip the box face down so you can see the back screws, remove all the screws along the edges. Gently lay the box flat like it would be on the bass-bin.

The crossover is mounted on the backplate so gently pry it off and lie it down(crossover up) and then pull the bass wires up threw the  bottom hole.

Disconnect the mid wires at the driver and then the tweeter wires at the  crossover circuit board. You can now move the backplate off to the side.

next flip the box face up to get at the motor-board crews and remove them. Then flip box face down and lift the box off the motor-board.

You now have easy access  to the tweeter screws.

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