[AMPS] Self oscillation with homebrew 3-1000Z ????

measures 2@vc.net
Mon, 7 May 2001 06:57:17 -0700


>
>Jim,
>
>I reckon there are two important steps in sorting a problem of this sort.
>
If the osc. is continuous, you cold find the freq. with a 
dipmeter/wavemeter.  

>1. Get some sort of spectrum analyser, or even a scanner, and find out what
>frequency the oscillation goes off at.
>
>2. Try to put a scalar analyser through the amp, firstly when its cold, and
>look for frequencies where there's a peak in response. You will probably
>find one around the frequency you measure in 1. You can then look for
>changes in circuit or layout that kill the peak. Once the peak is gone, you
>can repeat the test with the amp active.
>
>Ok, not everyone has a swept system, but you can do it with a very basic
>spectrum analyser and signal generator. You might have to spend a little
>time and beer money finding one to borrow, but it's a quicker and better
>route in the end.
>
I would bypass the high-tech research, cut to the chase, and try a lower 
Rp suppressor.  

cheers Steve

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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