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If you're like me, you know how annoying it is to use up 9V batteries on your guitar effect pedals. Its wasteful, and brand name 9V's are almost $9 for a two-pack. If you forget to turn off your pedals you've thrown away big bucks. Its an extreme waste of money when you can build your own power supply for only about $25.
The power supply I designed and built delivers steady, regulated 12 volts, 9 volts and 5 volts all at the same time. Each voltage has two outlets, but they can be "daisy chained" with a custom cable to connect many more pedals.
The styling is an homage to the old days of vacuum tubes, when components generated so much heat they needed to be on the outside of the casing instead of inside. I used some gigantic capacitors that I thought would look cool, other than that they are major overkill.
In this Instructable I am going to assume that you know some basic electronic skills and know what I am talking about when I say capacitor, resistor, LED, transformer, AC and DC, etc. There are lots of introductory electronics Instructables and soldering Instructables you can check out if you'd like to gain a better understanding of basic electronic principles and components.
IMPORTANT NOTE: Depending on what pedals you intend to use this for, you should take care to wire the DC connectors as pin-positive/ring-negative or pin-negative/ring-positive. The latter is the industry standard way of doing it, although it poses issues when building a pedal that has a metallic housing. I prefer pin-positive/ring-negative because of that issue, and I wired this supply in this way. Please take care as to which way you wire the power supply to prevent damage to your pedals.
The power supply I designed and built delivers steady, regulated 12 volts, 9 volts and 5 volts all at the same time. Each voltage has two outlets, but they can be "daisy chained" with a custom cable to connect many more pedals.
The styling is an homage to the old days of vacuum tubes, when components generated so much heat they needed to be on the outside of the casing instead of inside. I used some gigantic capacitors that I thought would look cool, other than that they are major overkill.
In this Instructable I am going to assume that you know some basic electronic skills and know what I am talking about when I say capacitor, resistor, LED, transformer, AC and DC, etc. There are lots of introductory electronics Instructables and soldering Instructables you can check out if you'd like to gain a better understanding of basic electronic principles and components.
IMPORTANT NOTE: Depending on what pedals you intend to use this for, you should take care to wire the DC connectors as pin-positive/ring-negative or pin-negative/ring-positive. The latter is the industry standard way of doing it, although it poses issues when building a pedal that has a metallic housing. I prefer pin-positive/ring-negative because of that issue, and I wired this supply in this way. Please take care as to which way you wire the power supply to prevent damage to your pedals.
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Signing UpStep 1Planning and Schematic
The first thing to do is design the circuit. Many guitar pedals and stompboxes have 9V DC power jacks on the back (if your's doesn't and you're feeling ambitious, you can add your own) which we will use to power them instead of the 9V internal battery clip.
The schematic I designed can be modified for whatever voltages you would like. For example, if you don't have any 5V pedals, you can just swap the 5V power regulator for a 9V regulator, and now you'll have double the 9V power.
The schematic uses a simple power supply circuit converting AC to pulsating DC, smoothing it with capacitors and running it through voltage regulators for fixed DC outputs.
Here is a higher resolution version of the schematic if you can't read the one below very easily:
http://img.photobucket.com/albums/v321/mattthegamer463/Schematic.png
The schematic I designed can be modified for whatever voltages you would like. For example, if you don't have any 5V pedals, you can just swap the 5V power regulator for a 9V regulator, and now you'll have double the 9V power.
The schematic uses a simple power supply circuit converting AC to pulsating DC, smoothing it with capacitors and running it through voltage regulators for fixed DC outputs.
Here is a higher resolution version of the schematic if you can't read the one below very easily:
http://img.photobucket.com/albums/v321/mattthegamer463/Schematic.png
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It's interesting when you have a near-standard like this, deciding what to do with the outliers.
Nicely made instructable, by the way. I love the look of the giant caps busting out of the enclosure, and how neatly you fit everything together inside.
I made a couple crossover cables for store-bought pedals, and an extra-long shaft for my Crybaby. all the pedals I make myself are pin-positive, simply because metallic enclosures mean that I have to do a lot of work to isolate the barrel jack from the enclosure. It just seems silly.
Rewiring pedals is difficult since most use board-mounted DC jacks, not much you can do without making a mess and compromising your pedal's professional build quality.
If there weren't any issues I would go with pin-negative just to make life easier.
Had a quick question - my transformer has two black wires and one green. I assume the green goes to ground on my IEC, but how does the wiring work for the two black ones? I am guessing one goes to neutral and the other one goes to live, but for the live one do I put the switch and fuse in between the IEC and the transformer so it goes like: IEC (Live) > Switch > Fuse > Transformer || IEC (neutral) > Transformer ? With a lighted switch, do I connect the ground to the earth ground on the IEC?
Thanks!!
I see that the regulators are 1A max and I jumped to the conclusion that 1A will be enough for 10 9V outputs as the BOSS DC Brick power supply uses an 18V 1A input and has 3 18V outputs and 7 9V outputs.
Running off a 12V battery you can cut the front of the circuit off at C1, but I would include a 1-2A fuse because 12V SLA batteries can deliver a lot of current, it is possible to start a fire with one so for safety it is best to include a fuse, in series, with the battery and the rest of the circuit.
Do you hear the noise out of your amplifier or is the noise from the power supply itself?
My design its simpler ,I did it for only 9v,. It took me a long time to understand the diagram and I more than triple check everything and did everything very carefully
One question..How many pedals can I daisy chain from a single line(or whatever its called)? , for what is worth I used the smaller 100uF capacitors and currently Im daisy chainning 2 overdrives and a wah without any problems, but I may add another one or two pedals more in the short future.
Thanks
Heres a couple of pics
Txs for the tutorial man, it's great
To find the current through the LED take the supply voltage minus the LED voltage (5V - 2.1V = 2.9V) and divide it by the resistance in series with the LED (220 ohm) and you get 13mA. A little lower than the maximum for the LED which is 20mA so it will work fine and not be too bright.
Thank you very much for the prompt reply.