Gregavi

You obviously didn't read my original post where I state "I replaced the crossovers a few years ago with a B&K Sound (AK 3) Xovers". You'd be right if they were the originals. That would make them the likely cause. I've recapped x overs that made a huge difference, especially in the high end. I've done more testing including swapping x overs and using a tone generator. I'm pretty sure it's a non working tweeter. I misdiagnosed at least once on this matter but I think I've got it nailed down to the problem being the tweeter and not the x over.

I've been driving them with the same amp for almost 20 years and it's the first time I've had a problem with the tweeters or any other speaker I've driven with this amp. I'm considering going with the CT120s. "Ferrofluid is a cooling / damping compound used in the magnetic gap of many tweeters to increase power handling and smooth out the frequency response; it has a tendency to thicken with age, gradually reducing tweeter output to zero."

Was there in improvement in SQ with the titanium in your opinion? Also, Simply Speakers has an option to add Ferrofluid. I know it's supposed to keep the coil cool but is it necessary? I drive my La Scalas with 300 Watts of super clean power so I'm wondering if it's necessary. Do they come from the factory with FF? I was under the impression that very few have FF.

Is it advisable to replace the diaphragm with titanium type if available? The ones I've seen don't list the K77 as one of the tweeters it fits so I'm guessing the replacement for the K77 isn't available in titanium.

6 Ohm. As I stated, I swapped x overs and the same tweeter does not work, which points to the tweeter and not the x over. Sorry for the confusion but my tests produced inconsistent results. Very frustrating. I have determined that the problem is with the tweeter. Now my question is, should I replace the diaphragm, the entire tweeter or replace them both with an upgraded tweeter like the Crites CT 120 or the Smahl V2? Anybody compared these tweeters and your thoughts?

I swapped x overs and the problem tweeter stayed with the same speaker which indicates a bad tweeter. The reason why I was assuming it was a bad x over is because the non working tweeter passed the Ohm and battery tests.

I swapped x overs & the speaker with the tweeter problem didn't swap with it. Looks like a tweeter issue. Was thinking it wasn't the tweeter bc I got results consistent with a good tweeter when I connected a battery to it got popping sound and it measured at 6 ohms. In your opinion, can the tweeter be blown even if it passed those 2 tests? I'm assuming yes.

I chatted with Michael Crites last night and he wants me to send it to him for repair. I am doing a full swap tonight as a last test before I ship it to him. I'm still not totally convinced that it is the x over that's the problem. He said, concerning the difference between the AK 3 vs the AL 3 "the AL-3 has a different tweeter circuit and slightly different woofer circuit. its not earth shattering changes, but likely does sound slightly different"

I did this. Tweeter is working.

Sounds great, when the tweeter was working.

Yes

I ran wires +/- from the known working xover tweeter connection to the non working tweeter and have verified that it is not the tweeter that has failed (the tweeter worked). Checked all the connections in the xover and they all seem to be tight.

I took the X Over out, cleaned it up a bit, tightened all the connections and re-installed it. (I wish all speakers were as easy access). Still the tweeter is not working.

I did this and it appears that the Xover is the culprit. On the speaker that is OK, the numbers jump around as you suggested. On the dead tweeter speaker, the number remained at Zero. BTW, on my volt meter I tried both V (volts) and mA (milliamps). The numbers went between 3 and 4 on V and of course higher numbers on mA. I checked most of the connections on the Xover board but I need to turn my speaker around to better access the Xover board. I will report back. Many thanks guys.