Ultrasonic Oscillation


Hi. I have had recent issues with my Snell Ds, tweeters not working. Anyway this led me to test of all of my equipment including my GMA Europas. Their tweets were dead also. I dropped an email to Roy at GMA and he suggested that I may consider the possibility of ultrasonic oscillation in either my amp or pre-amp. They are the Odyssey Candela pre amp, and Stratos amp. Could you please explain what it is, and more importantly what are the causes. Soon I'll get a diagnostic locally and sending the pieces to Klaus for repairs if needed. I look forward to your insights. Thanks much, Dave
italian
Hi, thought I'd follow up on this thread. I took suggestions to have my equipment bench tested, both sets of speakers as well as pre and power amp checked out OK. Set everything up, and now five months later HF still dead. Again and again yet I swapped all equip and wires. Problem still exists. I have been told it's not likely but can it be in my house wiring? I have also ran power to other outlet elsewhere in the house via heavy duty extension cord and same problem. Any suggestions, what can I possibly be missing? Yeah, I'm totally frustrated and at a loss. Thanks much, Dave
Italian, It sounds to me like your amplifier has too little power and you are pushing it too hard. That is why tweeters fail! Its not because of a malfunction.

So you either need a more powerful amplifier or more efficient speakers.
Hi Atmasphere, thank you for your response. I appreciate it very much. And a consideration that I had not considered. I have used my GMA Europas(4 ohm/88db/7-120W @ 8 ohm amp)for years with both an Odyssey Stratos amp at 150W @ 8 ohm and a Denon POA 1500 at 150W @ 4 ohm. I don't play my sytem at loud volumes. The GMA's are known as an easy load and are known to be driven with low power amps from what I have read here over the years. That really is what is vexing, until this year system played fine. Even the Snell's that are a more difficult load are pushed by tube systems of a lesser power then the amps above from what I have read also. This weekend I'll be taking the system to my daughter's house to see if the problem persists there no matter how dumb that may sound. No stone unturned. Again, thanks much. Dave
One other thing to look at is corrosion on the ground contacts of your RCA connectors. That can toast tweeters too.
Not sure why I read this old thread but I did. A very interesting read, and now I'm curious as to how the situation resolved. ???