[sdiy] Circuit noise / oscillation

[Harry Bissell]

should the oscillation get to a power amplifier, or to your tweeters, it might indeed damage them. You won't hear it but
it will still produce heat in the load...

H^) harry



----- Original Message -----
From: Justin Owen <juzowen at googlemail.com>
To: SDIY List <synth-diy at dropmix.xs4all.nl>
Sent: Thu, 27 Jan 2011 13:24:53 -0500 (EST)
Subject: [sdiy] Circuit noise / oscillation

Hey again,

I've been playing with feedback quite a bit lately - literally feeding part of an output back into an input.

I've got a curious little circuit here that, under certain circumstances, will begin to oscillate within audio frequencies - which is cool - but under another circumstance it starts oscillating right up at 130-135 KHz.

While the oscillations do appear at the outputs I only noticed it when I had the scope on the outs. There's no signal registering at my soundcard at all - even with *loads* of gain on the soundcard input and I certainly can't hear it!

It's reasonably well behaved, symmetrically shaped and it's centred on exactly 0V. It doesn't suddenly thump in from supply levels or jump around and freak out - so it's basically just self-oscillation out of audio range.

This circuit isn't meant to be linear or well-behaved - it's meant to scream and shout.

My question - can oscillations of approx. 7V PP at this high frequency range potentially damage other audio gear / modular Ins/Outs - or am I just chasing worrying about *stuff*?

Thanks.

J  

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-- 
Harry Bissell & Nora Abdullah 4eva