General Power Supply Question

[sluckey]

It's internal resistance of the PT. Multiplying by 1.414 gives you the unloaded voltage. You could measure close to that value if you remove all tubes except the rectifier. But with tubes plugged in the power supply will now have a load that will draw current. That current also causes a voltage drop in the PT secondary winding that causes the available B+ to drop.

[JoeTele]

Can the resistance of the power supply be determined (approximate value ok) so that voltage drop for a given current can be calculated/estimated?

Joe

[roberto]

DC resistance of the PT is usually an information given to customers, so yes, you can calculate the voltage drop.

[sluckey]

You may be interested in Duncan's PSU Designer...

http://www.duncanamps.com/software.html