2. amps-preamps
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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
atmasphere's avatar
atmasphere
11,966 posts
 
Italian, the volume control has nothing to do with the actual volume. With today's super high-output digital sources (a pet peave- there is no reason to have so much output) a 9:00 setting on the volume control might easily clip a lot of amps.

IOW it depends on how much output the source has too.

Another possibility is ultrasonic noise from the digital source.
dhl93449
455 posts
 
Italian

Anything you connect to the speaker output could potentially create an unstable situation, if the capacitance of the wiring is too high.

But this is very unlikely with a sub unless you are using exotic cables.

Did you upgrade interconnects prior to burning out your HF drivers?

SEVERE clipping can do this, but it would be so loud and unpleasant I doubt if you would not notice it.

Unplugging a connection to an amp or preamp with the volume up (that results in a burst of noise) can do this. But since you have destroyed TWO sets of drivers, this is unlikely.
italian OP
126 posts
 
Yes, i did switch to a set of DH Labs special edition ICs from pre to amp. Thin wires. Have a set of MAC palladium ICs from CDP to Pre but had been using them a while. Dave
italian OP
126 posts
 
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
atmasphere's avatar
atmasphere
11,966 posts
 
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.
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