DIY 48V Supply - Need a Schem

FastVinny · 3rd July 2009

I need to build a 48V supply for a single mic-pre. Anyone have a solid and simple schem for me to build. I understand schems, I just don't understand theory enough to design. I can make 48V with just a tranny, rect., and cap but I don't trust it for long term. I would like to use some kind of regulator. Any help

Matt Syson · 3rd July 2009

Hi
Cheapest and easiest for a single mic is a cap, resistor, cap resistor cap with zener diode (s).
Caps say 220 or 470 uF 100 Volt working. Resistors to suit voltage to be dropped at 20mA.
The max current draw from a phantom connected mic is 14mA and normally about 5mA.
If you get the zener (s) to draw about 20mA this will be sufficient. Use 2 , 24 Volt 1.3 watt zeners in series to get 48 Volts. About 1 watt total will be dissipated over the two zeners. The transformer and rectifier should give you about 60 Volts DC so needs about 45 to 50 Volts AC.
Matt S

Phil Feinman · 5th July 2009

I would say just check out Mouser and get a pre-built 48V PSU. They may also sell kits. Either way, they are pretty affordable and good quality. Regulated and all!

Stitch333 · 5th July 2009

FWIW: 5Fish and JLM audio have very good multiple PS kits with 48V rails....

3rd July 2009	#1
FastVinny Gear interested Joined: Feb 2008 Location: Nashville Posts: 5 Thread Starter	DIY 48V Supply - Need a Schem I need to build a 48V supply for a single mic-pre. Anyone have a solid and simple schem for me to build. I understand schems, I just don't understand theory enough to design. I can make 48V with just a tranny, rect., and cap but I don't trust it for long term. I would like to use some kind of regulator. Any help

3rd July 2009	#2
Matt Syson Lives for gear Joined: Sep 2004 Location: UK Posts: 4,822	Hi Cheapest and easiest for a single mic is a cap, resistor, cap resistor cap with zener diode (s). Caps say 220 or 470 uF 100 Volt working. Resistors to suit voltage to be dropped at 20mA. The max current draw from a phantom connected mic is 14mA and normally about 5mA. If you get the zener (s) to draw about 20mA this will be sufficient. Use 2 , 24 Volt 1.3 watt zeners in series to get 48 Volts. About 1 watt total will be dissipated over the two zeners. The transformer and rectifier should give you about 60 Volts DC so needs about 45 to 50 Volts AC. Matt S __________________ Matt S www.mseaudio.co.uk

5th July 2009	#3
Phil Feinman Gear interested Joined: Jun 2009 Location: Los Angeles Posts: 8	I would say just check out Mouser and get a pre-built 48V PSU. They may also sell kits. Either way, they are pretty affordable and good quality. Regulated and all! __________________ Phil Feinman www.philfeinman.com

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5th July 2009	#4
Stitch333 Lives for gear Joined: Aug 2006 Location: Phila, PA/Upstate MA Posts: 3,432	FWIW: 5Fish and JLM audio have very good multiple PS kits with 48V rails....