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Quad 909 oscillating. Why?

Something strange is happening with my Quad 909. It had been working fine but the other day I turned it on and even with no musical signal going through it and even with the preamp turned off I heard a loud oscillating sound coming out of my speakers. I immediately turned it off, grateful that it wasn't hooked up to my Quad 2805s when that happened.

Any idea what might cause this? I won't be trying to fix it myself but am thinking that it's a good idea to have a sense of what might be wrong before I take it in for a repair.


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georgehifi's avatar
georgehifi
10,312 posts
 
Was it HF "squeal" type oscillation, or LF "motor boating" oscillation.

If LF you may not of heard it through the ESL’ as they are transformer coupled and may not go low enough to produce it.
Try disconnecting the pre and interconnects and shorting the inputs of the 909 with shorted rca plugs, and see if it still does it. If so then it has to get looked at.

Cheers George
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