"Sizzling" tweeters at high volume?

I have my new SFC-1 tube amp (Svetlana El34) 50wpc. my speakers are ACI Sapphire II (Focal TK-120 kevlar tweeters)rated 15-150wpc, 90db with imp. of 6ohm. On some recordings (Live at the Greek, Tim Haggans...)snare drums, and trumpet would start to "crackle", at volume level past 12 o'clock. On other CD's it doesn't(Kind of Blue)
Dragen: Try listening to it in the morning, say around 10:30:-)
Probably cross-over damage. I remember something like this a couple years ago - it was a blown cap.
Sorry to hear that, but "sizzling" is actual "ringing", asociated with Kevlar tweeters. Look to upgrade to III, with new driver and ScanSpeak tweeter. You will love it.
the focal inverted titanium tweets should be a drop-in replacement - these tweets are what's in my meret re's, & i get no ringing, even at "head-banger" volume levels in a ~25x38 listening room... there was a cheap pair here f/s on audiogon last week...
It sounds likely that the amplifier is starting to clip at that point. Clipping causes a rapid increase in distortion such as you describe. Try backing the volume off just a little bit at a time until you get to the point where this no longer happens.
I guess David was right? Not to listen after 10:30 am.
Sedond, I find the Focal titanium tweeters to be the worst of the lot. Followed next, by the tioxid(TiO2). To my ears, the Kevlar tweeters are the least offending. I have also noticed that these tweeters are very system dependent. With a laid back tube amp, the Kevlar tweeters can be OK. With more forward sounding tube amps(I heard them with Rogue stereo and monoblocks w/Rogue 66 preamp) or many ss products, they send me running as fast as I can in the other direction. Of high end tweeters, the Focals are by far my least favorite.
hi trelja,

inneresting - many folks have similar comments about these tweets, but i like 'em a lot in my meret's, driven by electrocompaniet amps. as much as comparably-priced proacs, which i also like a lot, w/their dynaudio-derived tweets.

that said, i'm considering getting gnu speks - the (less-expensive) newform research nhb645's or the r645's, or a custom-wersion w/accuton drivers...

regards, doug

Good luck with the new speakers Sedond! I presume when you say Accuton drivers, you mean the ceramic(Al2O3, aka alumina) coned tweeters and/or midranges? If this is so, I think you are fortunate. I have heard(second hand) that these drivers are quite special. Used to see them a lot in the speaker parts catalogs I read(when I was "active" in the hobby), when they first came out. Were originally called Ceratec, then had to switch name to Accuton(or vice versa?), due to another company having dibs on the name. Lately, I have read a review of Kharma speakers(which I am under the impression use these drivers), and it was positively glowing. Supposedly very laid back and liquid, yet fully detailed. Please keep us informed of your reaction to the new speakers. Thanks

the newform's have ribbons from 1khz up; below 1khz, they currently run the scan-speak revelator mid-woofs, either 5.5" or 6.5", depending on the model. ya, the accuton mid-woofs would replace the scan-speaks - also excellent drivers in their own right. but, i have to believe that the accutons, which are a couple of orders of magnatude faster than the scan-speaks, would mate w/the ribbons even *better* than the scan-speaks. and yes, the kharmas, which *have* gotten good press lately, *do* use the accuton glass drivers.

regards, doug

Best of luck with your new speakers Sedond. Please let us know of your impressions during and after break in. Joe.