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High Frequency Oscillation hurt resistors in Magico A5 crossovers

Hi,I am looking for help understanding how HFO could blow crossover resistors in Magico A5 speakers. Equipment playing at the time of the incident is as follows...
Magico A5 speakersHegel H30 mono blocksHegel P30 preamp (lt and rt inputs on the Aux inputs from the laptop and Dragonfly Cobalt)
Dell laptopAudioquest Dragonfly CobaltAmazon Hi-res streaming
I was listening to Amazon music at a very moderate level when the application said there was an update available.I instinctively clicked accept while music was paying. It was only off for a few seconds to update and when complete and I restarted music the A5 tweeters were not on. These happened simultaneously and there was no audible noise what so ever indicating a potential issue. After multiple source tests and tweeter test, I was certain the tweeters were fine and it was an electronic issue. The cross overs were removed and sent to Magico and that was when I was told that HFO blew the resistors.
Can anyone explain how/why this happened so I can ideally avoid it happening again?
Thank you!
128x128howaanders8
fuzztone's avatar
fuzztone
5,636 posts
 
misstl has a point maybe they’re fuses in operation. Still, I would hope to get something in writing.
Good point that using a computer for source is dirty AND dangerous. Especially today with so many alternatives.
erik_squires
16,406 posts
 
Yep.  Makes sense to me.  What sent your amp into oscillation is the question.  This is one of the potential problems with very high bandwidth electronics.  If they can reproduce FM signals, you won't hear it, but your speaker wills smoke, one way or another.

I'd actually reach out to Hegel, as they may be better able to help you.

Best,

E
csmgolf
898 posts
 
The trite explanation you received sounds like it was from a low tier employee.
Maybe it was EBM.

howaanders8's avatar
howaanders8 OP
23 posts
 
"Very moderate" meant low volume that you could easily talk over jsyk.
I have emailed Hegel as well and am awaiting a reply.
audio2design
1,351 posts
 
+1 to this.  Look to your electronics, unlikely the PC put out high frequencies, but maybe it put out something that in combination with your electronics, cables and speakers started a high frequency oscillation.
erik_squires10,415 posts01-14-2021 4:51pmYep. Makes sense to me. What sent your amp into oscillation is the question. This is one of the potential problems with very high bandwidth electronics. If they can reproduce FM signals, you won't hear it, but your speaker wills smoke, one way or another.

I'd actually reach out to Hegel, as they may be better able to help you.

Best,

E

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