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Old 23rd April 2003, 05:35 AM   #1
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Default Oscillations-total newbie question

I'm a total newbie. Can someone explain in simple terms what this sounds like, what causes the various types and what precautions should be taken?

I have searched a bit for this info and really can't find anything at my level. Is there a simple answer?

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Old 23rd April 2003, 08:09 AM   #2
EC8010 is offline EC8010  United Kingdom
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Default Entire books have been written on this subject...

There are two types of oscillation that are likely in a valve amplifier, and you will hear neither of them. Motorboating causes your cones to move slowly in and out at about 1Hz, and is due to unwanted coupling in power supplies. RF oscillation happens at >30kHz, and you need an oscilloscope to find it. Meanwhile, it can cause the overall sound to be coarse and can fry output valves.

See if you can pick up a copy of "Foundations of Wireless" by Scroggie, this is a nice introduction to electronics.
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
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Old 23rd April 2003, 02:43 PM   #3
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Default Thank you

I appreciate your response. I'll keep an eye out for that reference.

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Old 23rd April 2003, 03:44 PM   #4
Joel is offline Joel  United States
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Actually, low-frequency "motorboating" is quite audible. That's why they call it "motorboating". It sounds like the tremolo on a guitar amp, cutting in and out.
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Old 23rd April 2003, 05:12 PM   #5
Gunders is offline Gunders  Norway
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You can have oscillations if you uncritically apply feedback to an amplifier, and often this is very hearable.
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