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
italian OP
126 posts
 
Do you think that the addition of a sub (REL Strata III) correctly connected to the amps speaker posts could create this instability in the amp? Again, thanks.
atmasphere's avatar
atmasphere
11,625 posts
 
Italian, one other possibility to consider is that if you have been clipping (overloading your amp with too much volume) then that will also damage tweeters.

Usually tweeters only have to handle a few watts but if you overload the amplifiers, the distortion that the amp makes can destroy the tweeters in a matter of seconds.
italian OP
126 posts
 
Atmasphere, clipping. I associate this with volume, loudness. I have old ears, on a clock with six o'clock being zero volume I drive the volume no more than 1/4 (9:00). Can this low level create a clipping situation? Please know, to all, I've learned alot through this thread, you all have provided a wealth of knowledge. Thanks much, Dave
atmasphere's avatar
atmasphere
11,625 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.
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