Adding phantom power (48vdc to 12vdc+phantom or 12vac to 48vdc+12vdc cheaper?

[iandy4]

Hi Everyone,

I started this thread two days ago, http://www.diystompboxes.com/smfforum/index.php?topic=91202.0 about getting phantom power from a 9vdc or ac power supply but I thought it might be better to start a new thread considering the subject has changed a bit.

Basically I am trying to add phantom power to this schematic:


Basically I just want to know what the cheapest option would be if I want phantom power and 9-12vdc for the circuit in the picture from one wall wart power supply.  Should I go with a 48vdc regulated power supply to go to phantom powering the mic input with a step down to 12vdc for the rest of the circuit OR a 12vac power supply with a step up to 48vdc (for phantom power) and a conversion to 12vdc?

Any help would be greatly appreciated!

The advice I got was that it might be easier to go with a 48vdc regulated wall wart instead.  But would it be cheaper?

[deepMago!]

A simple solution could be find in the Paia mic preamp:

http://www.paia.com/proddetail.asp?prod=9407K

Check in the schematic the voltage multiplier build around IC1 (CD4049), I have one build in a preamp, it gives only 43volts but seems ok.

[iandy4]

Thanks for the link.  It looks like a %^&*croft-Waston based multiplier which I've been looking into.

Can anyone tell me if this schematic that I just pieced together would work or if it's even in the right direction for getting regulated 12vdc and 48vdc from a 15vac supply?

If it is, can you tell me what the values of the caps should be in the regulation stages and if they are supposed to be electrolytic?



I've tested the rectifier part of the circuit by using a 9VAC power supply going through  four 1n4007 diodes and then to the original schematic that I posted and it seemed to function just fine without the regulation part of the circuit proceeding it.  The original schematic should function fine between 9vdc-15vdc so do I even need regulation for that?

[tempus]

I would use the regulator in any case - although your circuit may function with a range of values, it's probably better to keep it at a consistent value. Regulation also reduces ripple from the rectifier circuitry.

A question - is there such a thing is an 7848 voltage regulator?

You should read this:

http://www.tangible-technology.com/tubes/1566/power/Phantom_frying.html