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pedal board power supply

Started by DLM, March 19, 2012, 04:09:48 AM

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DLM

noob question - pedal board power supply
Hey guys , has anyone built a pedal power supply using  R.G. Keen schematic ? http://www.geofex.com/article_folders/spyder/spyder.htm I'm a noob here and have 1 build under my belt ( serendipity ) and it actually worked great ! But now I need power supply for that one and my other pedals . My thought was to build a power supply with RG Keens schem . Those who are familiar with it , I'll be using the Weber VST transformer  WPDLXFMR-1 , 110 v primary to 8 x 11v @ 300 ma and 1 x9v @ 2ma .
On  the schematic for the transformer , It says :  8  regulated hum free 9v outputs all of which are fully ground- isolated . All can be used as either  +9v or - 9v  or stacked ( 2 secondaries together ) to provide +18v or-18v or +/- 9v with a center tap . Okay heres where I need help understanding . On the schem for the Rectifier/filter /regulator , To get the -9v ( for  neg center post  for like fuzz boxes etc ) Do I switch the neg and pos on the rectifier/filter / regulator wiring ?  And what is +/- 9v center tap mean ?  What I want to do is run some +9v jacks and some -9v jacks  . Any Help would be appreciated    

impetus maximus

110V? where do you live? here in the US we get 120V out of those holy thingies in the wall.  :P
running 110V trannys @ 120V will give you more than you need/want. *cough Fender reissues *cough

just a friendly heads up. good luck with your quest  :)

/max

impetus maximus

as long as your getting the voltages you desire and aren't overloading anything.  ;)
wish i could be more help.

i want pics when you start building this bad boy.

/max

Tpetty5

I think you would need to use a 7809 voltage regulator instead of a 78L09 for positive ground output.

plesur

No, for -9V regulation you would use 7909 or 79L09.

DLM

Hey guys thanks for your input . I thought I had a good idea . I went to a another site (free stompboxes ) and it seems this subject has been beat to death !  I still need to make a power supply so if you guys can turn me on to something easy to build I'd appreciate it .   I've been looking at the road rage it seems pretty easy to build , I don't know how many jacks it will support . But if i can build it to support my neg post pedals  say 4 or so with maybe 4 pos all at 9v it would work for now . All 4 of my pedals have right now have 9v neg  center posts and I'm using wall warts for each plugged into a power strip . WHY ?  Because I'm to broke and to cheap to buy a brick if I can make one . Besides its fun to build stuff and hide from the wife and 2 teenage daughters . They'er all out to kill me I tell ya ! LOL  . HEY are all pedals NEG center post ?  I guess I need to do more studying to be able to understand what going on and what you guys a talking about cause I'm lost . I'm a monkey see and monkey do kind of guy . Thats how I learned to play the guitar . I suppose thats why  I had to get a real job . Or was it getting married and having 2 teenage daughters and their dumb-ass , No job , boy friends eating all my food ? I 'm sorry for rant . I know some of you know what that about LOL ! Anyway ..... a  kit version would be best thing for now I guess . Or I'll build the road rage and be back asking a million questions LOL  Thanks DLM

nzCdog

Hey man.  

Yeah most pedals are 9V Centre pin negative... but thats not always a given, so always check the power requirements of your pedals before pluggin them in, and if your not sure just ask someone first ;)

How much current output do your 9V wallwarts give?  It will give a rating in mA or A.  Anything over 300mA could prolly power a bunch of pedals.  Most pedals only draw a small amount of current so with a daisy chain you could power them all off one wart potentially.   I had a 9V boss adaptor that gave 1A output and used it for a board of 9 pedals before I built my power supply... it was great never had any problems.

To run my pedals that require -9V supply (Fuzz, treble booster) I put a Road rage inside the actual pedals, so now they all just take normal 9V supply... that keeps it simpler IMO, less chance of putting the wrong power into a nice fuzz box ;)

Unless you have hum problems... I would try daisy chaining from one wallwart.  I did this for years, it worked perfectly





Ettore_M

#7
Hey, Corey. A great advice you gave us, mate. Much appreciated!
So I was thinking... I found a 12V 2A wall wart supply on the ebay (really cheap), so I don't know if it's really regulated, and I was thinking (again) to build a distribution box for regulated 9V and 12V, and use a Road rage for -9V and 18V. Is the current enough to supply a bunch of pedals? How would be the circuit? some resistors and capacitors and a 7809 for the 9V (except the road rage)?

Hector
" I would first try what I call The American Approach, which is simply this: "If X is good, then 2X simply HAS TO BE twice as good."  ;D "
- Culturejam

nzCdog

#8
Hey Hector, yes thats heaps of current!  

Regulating to 9V would be simple... regulating to 12V not so easy with only 12V of supply, although it may be regulated already? To regulate to a voltage you need a bit of headroom on the input, maybe 1.5-2V  above your output voltage for the IC to work properly, so that will depend on the output of the wallwart when it's under load.

You could build a very simple regulator/filter setup on vero or something and have a roadrage for the -9 and 18V.  You could do another roadrage for 12V as well if required. Look at the datasheets of the ICs for suitable schematics and remember to heatsink the ICs!

Its not too difficult making a regulator setup like this from a wallwart, and much safer than wiring a transformer up yourself.

Ettore_M

Yes indeed! It's not the right time for me  to get into trannies and lethal high voltages.  :-\

So thanks again for the advice. So I'll look into it, try to make a schematic and post it for you to confirm if it's right.

Hector
" I would first try what I call The American Approach, which is simply this: "If X is good, then 2X simply HAS TO BE twice as good."  ;D "
- Culturejam

nzCdog

Absolutely, feel free to PM me any time and be sure to share your results! :)