some years ago I started to build a mic preamp with phantom power supply.
I bought a 2x15v transformer as main power and for the phantom a... 2x12v transformer.
What strange drugs did I take to get this idea? How can I get 48v from 2x12v transformer?
(https://media.giphy.com/media/CiYImHHBivpAs/giphy.gif)
I bought also every component to build this project and there is no charge pump or something similar.
Only a 48v zener diode.
Voltage doubler?
(https://www.learningaboutelectronics.com/images/Voltage-doubler-circuit.png)
dave
you're right!
my knowledge is regressing :-\
Are there some advantages using a full bridge rectifier?
like this:
(http://www.theorycircuit.com/wp-content/uploads/2019/06/12V-to-24V-Voltage-Doubler-circuit.png)
Doubling the voltage the current is halved, right? the transformer is 0,5VA (2x0,25). so the current should be about 20mA?
If i recall, peak voltage with a doubler is 2.8 times the secondary so i've gone with the ampere rating divided by the 2.8 factor. I've used the simple version in a number of tube amps for the high voltage rail, they've run with without issue for years. No idea whether the bridge may offer in improvements.
dave
So, 24*2.8=67.2. That's why I also bought a 48v zener diode.
The schematic attached should be fine. But I think I have to add a resistor on the red circle. right?
Thank you very much for helping me!
Your welcome.
The resistor, i don't know but, there is this project for a phantom 48v supply from Rod Elliot that uses a voltage doubler, he has a small value resistor in each power line.
(https://sound-au.com/p96-f1.gif)
https://sound-au.com/project96.htm
dave