DIY 9 Volt Power Supply Help

[HOTTUBES]

I want to build a 9 Volt power supply that i can use on my workbench as well as my pedal board etc ...


This is what i have in spare parts laying around that i think i could use for the build :

1. Small Step Down Transformer @ 50 v/ac output
2. Three (3) 7809 voltage regulators .
3. Ten (10) 2.2K  ( .5) watt
4. Very good assortment of caps , diodes , LEds
5. Vero board
6. Five (5) 2.1 mm DC Output jacks
7. Large size hammond enclosure

Now i just need some guidance on building  it !!    



Thanks for any help !

[armdnrdy]

I would say that the 50vac secondary transformer is out. Too much power to dissipate stepping it down to 9 volts.

You might want to think about building a supply with other available voltages as well since you are starting from scratch. This way you won't be limited to just 9 volts.

[PRR]

You can pay a $9 lunch-check with a $50 bill and expect $41 of change.

You normally will NOT want to "pay" a 9 Volt need with a 50 Volt supply, because you don't get "change", just heat.

Agree: find a 12V supply. Goodwill odd-warts shelf, or Radio Shed.

[HOTTUBES]

Makes sense !!
And the truth is i only need to power up 4 , 9 volt pedals , that are mostly dirt boxes that don't draw alot of mA .
I'll look around and see what i have ....

Will a 12 volt dc wall wart work here ? ( i think i have one of those )

[HOTTUBES]

So i checked my tickle trunk to find that i have 3 possible alternatives for power ...


Wall Warts

1. 12 Volts DC @ 1.0 amp
2. 12 Volts Dc @ 300 mA
3. 9 Volts DC @ 1.0 amp


Will any of these work for my intended purpose ?
Does it matter if they're  a " Dirty Power " source ?

[armdnrdy]

You can use the 12VDC 1 amp and do something like this:

http://www.muzique.com/images2/power4.gif

Use the input section and the section labeled: IC1-IC4

9 volt regulators in parallel. The filter caps at the front of the circuit coupled with the regulators should "clean" up the power.

The filter caps can be sized as big as your enclosure will allow. You can lay the caps horizontally if need be. Look to 470µf to 2200µf electrolytics for C6 & C7 cap values. C8 will be a .1µf poly film. The cap on the "load" side of the regulators can be 10 to 100µf.

[HOTTUBES]

Awesome  !!

Thanks Larry !

How many 2.1 mm outputs can i run with this ?

Could i run 2 off each 7809 reg. ?

My thinking is if you have 4 , 2.1 mm dc jacks with a draw no greater that 600 - 700 mA , i should be fine

[HOTTUBES]

Question about C6 - C7 caps ...

Does cap value matter here ? 
Will a 1000 uf cap do the same filtering as the 2200 uf cap ?
50 volt rating i assume is good enough here ??

[HOTTUBES]

Ok , Thanks to armdnrdy's ( Larry ) link , i was able to spin this up in the last while etc etc ....
I'm thinking that it should work just fine imo ....
I just put it on a small piece of vero i had sitting here ...
Wall wart voltage goes in to the board on left side , then the regulated 9 volts exits out the right side wires etc etc ...










Feel free to critique !!  ( i'm just a noob  )

[R.G.]

Good noob reading: Power Supplies Basics at http://www.geofex.com/Article_Folders/Power-supplies/powersup.htm

Much more than a paint-by-the-numbers kit.

[Jdansti]

Nice job!  You might want to keep an eye (or finger) on the temperature of your regulators to see if you need heat sinks.

[HOTTUBES]

Nice job!  You might want to keep an eye (or finger) on the temperature of your regulators to see if you need heat sinks.

Yes , good call , I was thinking the same thing ....

[HOTTUBES]

Thanks for everyone's help !!

I hooked up the wall wart ( source power ) last night to this little board , and checked it with my meter , it shows a perfect 9.05 v dc !!
But the true test will be how clean it sounds with guitar plugged in & playing !

I'm crossing my fingers !

[armdnrdy]

Nice job!  You might want to keep an eye (or finger) on the temperature of your regulators to see if you need heat sinks.

Yes , good call , I was thinking the same thing ....

If you are just powering 4 "dirt boxes" as you stated you shouldn't need heatsinks.

"the true test will be how clean it sounds with guitar plugged in & playing"

It all depends on proper filtering.

[HOTTUBES]

So , to take things one step further , i built this little DC power filter circuit to tag on the end ....









Thanks for everyone's help !

[Roger Martin]

May i know the schematics and BOM please?
Sounds promising 

[HOTTUBES]

May i know the schematics and BOM please?
Sounds promising 

Link to Regulator section ....


http://www.muzique.com/images2/power4.gif

[HOTTUBES]

link to noise filter ....


http://www.beavisaudio.com/projects/Huminator/

[Henry89789]

Hottubes: Thanks for the links. I was interested in the schematics and BOM also. I've seen the schematic for the regulator section before but it doesn't have the values for all the components.  I went to the web site from which it comes but couldn't find any info re: the component values. Can you provide the component values or tell where they come from? Thanks.

[tommycataus]

+1

As a newbie I'd be interested in getting a list of values for components for this project, been looking for a decent schematic for this project for some time! Thanks HOTTUBES