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.
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.
Hi lordvader,
Try slow blow or antisurge fuses instead. Maybe the inrush current from the 1.5A plugpack is enough to rupture the 500mA quick blow types.
See ya,
Tim.
Try slow blow or antisurge fuses instead. Maybe the inrush current from the 1.5A plugpack is enough to rupture the 500mA quick blow types.
See ya,
Tim.
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
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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