Is there a way to split 24v DC to 1 x 24V and 1 x 12v DC?

[Spider27]

Hello,

 

I am building a preamp with phonostage and preamp circuit takes 12v ~ 15v DC but phonostage board takes 24vDC.

 

Instead of using two separate power supply, would like to check if 1 x 24v DC input can be converted to 1 x 24vDC and 1 x 12~15v DC output. 

 

What would be the simplest way to split into 2 separate output with 2 different voltage?

 

Any tip would be great. Thank you.

[Monkeyboi]

Use a 12 or 15v linear regulator from the 24v supply.  Inexpensive, few components required and an easy DIY project.

You will need to know how much current the preamp part will draw.  This will determine the regulator IC and how much heat sinking it will require (if any).

 

[Spider27]

47 minutes ago, Monkeyboi said:

Use a 12 or 15v linear regulator from the 24v supply.  Inexpensive, few components required and an easy DIY project.

You will need to know how much current the preamp part will draw.  This will determine the regulator IC and how much heat sinking it will require (if any).

 

 

Thank you very much, Alan.

 

I am planning to use 24vDC 2A power supply and,

 

Preamp needs 12vDC about 250mA

Phonostage needs 24vDC  250mA

[Monkeyboi]

You could use the LM7812 for 12v.  Calculated power dissipation would be 3w of lost power.

You could use the LM7815 for 15v.  A little less power dissipation of 2.25w.

 

[Spider27]

11 hours ago, Monkeyboi said:

You could use the LM7812 for 12v.  Calculated power dissipation would be 3w of lost power.

You could use the LM7815 for 15v.  A little less power dissipation of 2.25w.

 

 

Thank you very much, Alan. I will try LM7812. 

[stereo coffee]

But unfortunately 78XX are a poor choice for audio related circuits, fine for washing machines though. Why this is , is because 78XX were designed principally for large circuit boards where there was ability to remove capacitance, hence you can measure a fixed resistance at their outputs to their ground terminals making them a shunt circuit with purposed  no ability of high impedance.

 

The criteria for audio circuits is to achieve ridiculously low ripple , high impedance, current regulation, more so than voltage  and stability.

 

You therefore need to look at a capacitance multiplier with a preceding common gate or base stage. Mosfets are IMO better. The circuit   will need method of controlling the base or gate to enable needed voltage regulation, but the emphasis should be assessing current use in the circuit firstly. The best circuit for this is the common gate or common base where the emitter or source is the input , the gate or base is grounded, and the collector drain is the output. arrange resistance to set the circuits expected delivery at the collector or drain. You then have a very effective high impedance circuit with desired current delivery - which is a great starting point. .

Edited June 19, 2023 by stereo coffee

[Monkeyboi]

2 hours ago, stereo coffee said:

But unfortunately 78XX are a poor choice for audio related circuits, fine for washing machines though. Why this is , is because 78XX were designed principally for large circuit boards where there was ability to remove capacitance, hence you can measure a fixed resistance at their outputs to their ground terminals making them a shunt circuit with purposed  no ability of high impedance.

 

The criteria for audio circuits is to achieve ridiculously low ripple , high impedance, current regulation, more so than voltage  and stability.

 

You therefore need to look at a capacitance multiplier with a preceding common gate or base stage. Mosfets are IMO better. The circuit   will need method of controlling the base or gate to enable needed voltage regulation, but the emphasis should be assessing current use in the circuit firstly. The best circuit for this is the common gate or common base where the emitter or source is the input , the gate or base is grounded, and the collector drain is the output. arrange resistance to set the circuits expected delivery at the collector or drain. You then have a very effective high impedance circuit with desired current delivery - which is a great starting point. .

 

Whilst I don't disagree with your comments, I would suggest @Spider27 is looking for a simply DIY solution for a person with limited electronics knowledge.

Yes, there are certainly better solutions but unless you are prepared to share a practical circuit and PCB layout with @Spider27 IMHO he'd be better off with a simple three component solution.  In addition we know nothing about the requirements of the pre-amp in question except it required a single ended supply of 12 - 15 volts @ 250mA.  We have no other information to go on.  Besides if the pre-amp design was half competent it should have a half decent power supply rejection ratio.  After all it's a line stage (presumably) as the phono stage is using the 24v supply.  If anything this stage needs a pretty clean supply and I half suspect this 24 volts is sourced from a plug pack or relatively simple supply.

 

Of course in our sharing and caring community perhaps you might want to publish here a design as you have described and a PCB layout @Spider27 can send off to PCBWay or another supplier to be manufactured for relatively low cost.