Quote Originally Posted by the great waldo View Post

Do you think it's not worth bothering with the bleed resistor ?
Bleed resistors are pointless, unless you have a very high voltage and you must work with the equipment, for example a camera flash, which is potentially dangerous unless you drain the capacitor, or measure the voltage and KNOW that the capacitor is discharged, which can take a very long time in case of a flash. In normal power supplies it will be drained after maximum a few minutes, even without any bleed resistor because you most certainly have some things, like a driver, or other electronics connected to it. Bleed resistors are just waste of energy when the PSU is ON. In your case, 50VDC isn't a risk anyway, unless you are easily scared. You may feel it, but nothing more. Besides, it can't be charged to more than 50V anyway. The fact that you are using 100V capacitors says nothing about the stored voltage, only that the capacitors can be used up to 100V. Your capacitors will never be charged over 50V if the PSU is 50VDC out after the rectifiers.

What I think is MUCH more important is that you have a slow starter circuit, because toroidal transformers draw a lot of current at start up and they can blow the fuse, or start with a very loud bang. Slow starter circuits are placed on the primary side and they limit the current for a short period (typically about 2 seconds), while the large capacitors are charged. This is necessary because the large capacitors short circuit the secondary side for a short time when they start to charge. The current rush cause the large bang and can also blow your mains circuit breaker, or fuse in the wall plug if you have one.