Multi build: 12v to 9v step down regulator?

[vizcities]

I'm in the midst of doing a multi build where two effects (EA Trem, old Rub-A-Dub verb w/BDTR-2H) are traditionally powered at 9v and the other thing, a Ruby Bassman amp, works best at 12v. My plan is to decouple the shared power with a daughter board, but I had two questions:

a) Will the two effects circuits be negatively affected if I run them at 12v?

And, if so...

b) Does anyone know how to step down from 12v to 9v using a regulator?

Multis are definitely a brave, head-scratching new world for me, so any light you folks could shed would be welcome 

[m-Kresol]

a) I don't think it would be a big problem to run them at 12V. Just make sure to have the correct voltage ratings on the electrolytics, but I doubt you'll find any under 12V anyways. The internal 5V regulator in the rub-a-dub might get a bit hotter, but it's nothing it can't handle.

b) just have a look at the datasheet of a 78L09 or LM7809 regulator. I would recommend the latter though as it can handle more current. You'll find the pinout there with IN/OUT/GND. Hook up the 12V to IN and GND to GND and you should have 9V under load at the output. Then put a 47u-100u electrolytic cap between Out and GND to stabilize the voltage a bit. negative end towards GND.
http://pdf1.alldatasheet.com/datasheet-pdf/view/105706/FAIRCHILD/LM7809.html

[Willybomb]

Stepping down from 12 to 9 is fairly straight forward all things being told.  If you have both a 12v and 9v regulators you can run them in series, powering the 9v regulator off a feed from the 12v regulator, or you can run them in parallel off a higher voltage.

I used a couple of different ideas in my SloppY, but this was pretty useful.  Keep in mind he does center positive or something because he uses uninsulated jacks in his diy pedal builds, but the schematic is good.

http://www.instructables.com/id/Build-A-Power-Supply-For-Your-Guitar-Pedals/?ALLSTEPS

Something like this would work fine, just replace the transistors with the regulators of choice.  Easy to get up or downsize this one.

[flanagan0718]

I use this exact layout for my work bench power supply. It brings 18v down to 9v nicely.


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[alanp]

Bear in mind that the more voltage it has to drop, the more heat it has to dump, which adversely affects it's maximum current rating.

(Disclaimer: I am just a meatworker.)

[madbean]

I love that disclaimer Alan.

I would try and run them all at 12v. Of course, it's not a big deal to use a 12v supply on a 9v regulator (+3v usually being the minimum) but once you get into delays and reverbs that means you will be running a second 5v regulator off your 9v regulator. For that reason, a single 7809 is probably the better choice than multiple 78L09 and then just share the non-isolated 9v power between the effect circuits and the unregulated 12v to your Ruby.