I am trying to build an audio project that requires +-25 to 50vdc I have put the secondary wires from a 50vac transformer into a rectifier full bridge I think g3sba20. Where do I get a ground to complete the circuit? From the chassis of my amp, or?

 

You don't need ground.

Would you please post your schematic?

 

You don't need ground.

Would you please post your schematic?

I don't have a schematic. The amplifier board has a spot for the + voltage, one for the - voltage, and a spot for a ground

 

I don't have a schematic. The amplifier board has a spot for the + voltage, one for the - voltage, and a spot for a ground

I'm trying to make a dual dc power supply with what I got

 

I don't have a schematic. The amplifier board has a spot for the + voltage, one for the - voltage, and a spot for a ground

It's difficult to help you without a schematic.

 

I'm trying to make a dual dc power supply with what I got

Well, with what you told us you got, you can’t.

Do you really need a variable DC output? Or do you need a dual 25VDC power supply? Like 25VDC - 0 - 25VDC?

Even a sketch of the schematic will help…

 

I am trying to build an audio project that requires +-25 to 50vdc I have put the secondary wires from a 50vac transformer into a rectifier full bridge

Your requirements aren't clear.

1. Do you require -25V and 25V that's adjustable to 50V (but not -50V)?
2. What current do you require?
3. What is the current capability of the transformer?
4. Is the secondary center tapped?

The transformer you want to use doesn't seem like a good choice unless you use switching regulators, but regulator noise could be problematic for an audio project. You could put linear regulators after switching regulators, but it'd be better to pick a transformer with a more appropriate secondary voltage.

 

I have put the secondary wires from a 50vac transformer into a rectifier full bridge I think g3sba20. Where do I get a ground to complete the circuit?

Most audio amplifier power supplies I have seen are unregulated and if you want a dual supply as in +25 volts and -25 volts you start with a center tapped transformer and the center tap becomes your ground. I suggest you Google "dual power supply schematics" as a starter. Your narrative is a little weak but I gather you are looking to power an audio amplifier.

I'm trying to make a dual dc power supply with what I got

Then I hope you have a center tapped transformer.

Ron

 

It's likely your secondary 50VAC needs a center tap. Hence, the comment on post #

you need a dual 25VDC power supply? Like 25VDC - 0 - 25VDC?

And for audio you're going to need to filter that rectified DC. your 50V will become over 70VDC Filtered. Or 35VDC - 0 - 35VDC.

Most audio amplifier power supplies • • • are unregulated and if you want a dual supply as in +25 volts and -25 volts you start with a center tapped transformer and the center tap becomes your ground. I suggest you Google "dual power supply schematics" as a starter.

Ron

Quote partially edited
The reason for quoting Ron is because he's right. And so is DJ. Whether you get a dual power supply or build one yourself, you're going to need a good plan and schematic. It's the road map to building anything electronic. Unless you're building a flashlight. In that case all you need is a battery, some wire and a light bulb. But for an amp you're going to need a lot more than an idea.