Re: Talema power transformer hum - Check for oscillations - BFP

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Re: Talema power transformer hum - Check for oscillations

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In Reply to: Re: Talema power transformer hum - Check for oscillations posted by Ron on November 8, 2000 at 17:04:16:

I have heard this happen when a regulated power supply under load begins to oscillate. My experience is with commercial/industrial equipment in a laboratory environment. The cause is usually a bad filter cap. or some malfunction in the load that is causing it to draw too much current.
When you say high frequency noise I am assuming that you do not mean 60 or 120hz noise. Sometimes, transformers can buzz when under heavy load or with highly reactive loads. Toroids are less likely to do this and if the transformer is properly sized for the load you shouldn't get any noticable noise.
First, check for overheating components. If the transformer is working hard then the power it is suppying has to be going somewhere.
If you have a good multimeter you can do a basic check on your power supply. I am assuming you have a regulated power supply.First, meashure the regulated + and - DC voltages outputs to assure that they are correct. Switch to AC volts and meashure the same points. If you see any AC above a few millivolts you could have an oscillation or load related problem.
You can troubleshoot many problems with a multimeter but there is no replacement for an oscilloscope to see what is going on in a circuit. It is always risky to build or modify any circuits that use High speed op amps without making sure that things are absolutely stable. You could end up damaging your speakers if you have a HF oscillation.
Hope this helps,
Brian

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Follow Ups Full Thread

Topic - Talema power transformer hum - Ron 07:52:15 11/07/00 (7)

Re: Talema power transformer hum - Check for oscillations - BFP 08:59:35 11/08/00 (3)

Re: Talema power transformer hum - Check for oscillations - Ron 17:04:16 11/08/00 (2)

Re: Talema power transformer hum - Check for oscillations - BFP 07:54:35 11/09/00 (1)

Re: Talema power transformer hum - Check for oscillations - Ron 20:46:16 11/09/00 (0)

Re: Talema power transformer hum - Dan W 10:46:34 11/07/00 (2)

Re: Talema power transformer hum - Ron 14:50:22 11/07/00 (1)

Sorry, I dunno! (nt) - Dan W 15:02:24 11/07/00 (0)

Follow Ups

Re: Talema power transformer hum - Check for oscillations - BFP 07:54:35 11/09/00 (1)

Re: Talema power transformer hum - Check for oscillations - Ron 20:46:16 11/09/00 (0)

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