Help with rectifier circuit

[jetbat]

Hi, I am building a power supply for a microphone preamp, +24V, with phantom power, +48V. The +48V is going to use less then 10 mA and the +24V will use around 105mA. I've attached a picture of two rectifier circuits I am thinking about.

Are there any problems with either circuit and which one, if any, has advantages over the other?

Thanks
Scott

 

[nigelwright7557]

At a quick glance.

The first one wont work as you need a common ground.
Connecting zero volts on one to zero volts on the other will blow up the bridge.
Or, I could be wrong.

 

[jetbat]

Thanks for the reply. As you can see I am still new to this. I have two more circuits.

The first is with a voltage doubler. I'm not sure if the grounds can be tied together like this. Also does the unloaded output voltage of a voltage doubler = Vin*1.41 the same as a bridge rectifier.

The second one is suppose to work but I just need conformation of this.

Thanks
Scott

 

[nigelwright7557]

Thanks for the reply. As you can see I am still new to this. I have two more circuits.

The first is with a voltage doubler. I'm not sure if the grounds can be tied together like this. Also does the unloaded output voltage of a voltage doubler = Vin*1.41 the same as a bridge rectifier.

The second one is suppose to work but I just need conformation of this.

Thanks
Scott

You cant tie the grounds together on the first one it would blow the rectifier.

 

[jetbat]

Is there any problem that anyone can see with the second circuit in the second picture?

 

[RJM1]

The second one will work an give you +24 and +48V.