Problems with Rod Elliot's Project 05 (power supply)

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Hi.
I've almost finished building a preamp based on most of Rod Elliots projects. I am, however, having trouble with the power-supply.

I did some testing with a 5W, 22Ohm resistor in series with the AC (before the rectifier), and was able to measure the +/- 15V on the outputs.

When I remove this resistor, the fuse blows. I'm using 500mA, quick-blow fuses, and my powersupply is a 16V, 1.5A AC powerpack.

Any help would be much appreciated. My electronic knowledge isn't the best (I skipped most of my EE lectures ...), so please excuse me if this seems a silly question.
 
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Joined 2002
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PSU problems

Most probably you have a massive supply cap in the preamp, that acts like a short to the poor power pack at switch-on. Since this is only a problem at switch-on, Tims's advice will save you, but negates the protection of the power pack. A better solution is to use say 1 or 2 ohms from the powerpack to the preamp supply caps and see if the original fuse stays up.

Jan Didden
 
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