Build your fx power source power supply

before starting

Today, we’re going to build together the latest FX Teacher product: the FX Power Source! For once, it’s not a pedal, but a power supply!

If this is your first FX Teacher kit, I advise you to check out the blog and discover our methods. I consider in the rest of the article that all this will be largely acquired!

If you have already made a dozen kits and a simple BOM is enough for you, we also thought about you. Zap the pedago/theoretical part and download the doc directly!

Whether you’ve already soldered a dozen pedals or not, a bit of theory never hurts! You will find all you need in our articles, to learn more about how a pedal works and the different effects, their history…

Disclaimer : If you’re in trouble with a step or you don’t understand something, we will be happy to help you. For this, leave a comment with your request on this blog post. This project is even so DIY, so it is up to you to make your own decisions and responsibilities, and to check what you are doing before going ahead. You will be answered as soon as possible and this answer will allow other readers to go forward.

Don’t be surprised if your comment doesn’t appear immediately, we have to validate it to avoid spam from certain robots. To recap, no emails, no chat, no calls regarding DIY, only requests on comments section please. Otherwise, it’s unmanageable for us.
Please also check that your request has not been treated, also that your tensions are good and that you have followed all the steps 🙂
If you feel that you need to be coached, you can join one of our masterclasses, they are made for you ! 😉

plan

• fx power source presentation
• the theory behind each pcb
• solder the pcbs
• assemble the power supply

what you can do with the fx power source

The FX Power Source has been designed to be as modular as possible! The concept is simple: you have several PCBs, each with 2 pedal outputs. When you solder them, you can choose to have 9, 12 or 18 V on each board, depending on the components. Then you can connect as many of these boards as you want together, to create your custom power supply!

We propose you a basic kit with 4 SUPPLY PCBs, so 8 outputs! Then, if you need to expand your power supply because you have bought new pedals, you can order each PCB individually. You can put as many as you want!

Each PCB can supply up to 200mA. So you can connect 2x 100mA pedals on one PCB. Or one 200mA pedal leaving the other output free. This is more than enough for analog pedals, and most digital pedals!

All our power supplies (Anasounds K+ and FX Power Source) have a 24V THRU output. This allows you to connect the 2 power supplies together, and have only one power cable coming out of your board! So you can have one power supply on each side of your board, if you want to avoid having power cables running through your board.

With your power supply, we give you 2 brackets, which we designed to be easily fixed to most pedalboards. And moreover, they are made locally, by a company in our city! We show you how to fix them on different pedalboards we tested in this article.

structure of the fx power source

Now that we’ve introduced the power supply, let’s see how it works, while we’re assembling it!

24v power supply

Before coming into the power supply unit, the mains voltage must already be adapted to a signal that can be used by our power supply unit. This is done in several steps by lowering the voltage and transforming the AC signal into a well-filtered DC signal.

We could have been able to develop this part, but we decided not to bother with all the problems of norms and certifications that a mains power supply implies. So we turned to a ready-made and high quality power supply, which will transform the 230V AC of the outlet into 24V DC. So there is no dangerous voltage going through the power supply you are going to build!

Having an external power supply also has another advantage. The 50/60 cycle AC signal from the mains can interfere with the outputs of our power supply by electromagnetic radiation. And since it is an audible frequency, it can be heard! This is the famous hum noise.

By placing the power supply section far away from our power supply unit, radiation is prevented from reaching the pedal outputs! Moreover, this power supply is a switching power supply. This means that it will cut the signal at several hundred kHz, to lower the voltage. So there will be no 50/60 cycle that can reach the power supply. And the switching frequency is inaudible, so no risk of hum noise!

If you want to learn more about the different power supply technologies, and how to convert from 230V AC to 24V DC, you can check out this article. We talk in more detail about how each technology works and the advantages and disadvantages of each technology.

build your fx power supply fx power source

Come on, let’s get started with the PCBs you’re going to assemble!

There are 3 PCBs:

• the 24v in, which will take the 24v dc from the external power supply, and distribute it to all the other pcbs.
• the supply, which will lower and regulate this voltage to 9, 12 or 18v according to your needs, to supply your pedals.
• and the 24v thru, which is a 24v output to connect to another anasounds or fx teacher power supply.

So you will have a power supply that looks like a sandwich of PCBs, with a 24V IN PCB, a 24V THRU PCB, and all your SUPPLY PCBs in the middle!

Ready ? Then take your tools and your soldering iron, we can start to assemble your power supply!

If you’ve never soldered before, you can take a look at this article as well, it will help you a lot:

apprendre à souder comme un « pro » !

the 24v in pcb

We start with a simple PCB, the 24V IN!

It couldn’t be simpler! On the left, there is the 24V DC coming from the external power supply (the 2 white connectors). On the right, these are the pins that will allow you to connect your other PCBs.

In the middle, we have a diode and a capa. The capa will be used as a filter, because even if we have a perfectly clean 24V DC at the input, it’s always good to filter again just in case! The capa will also act as a tank, that is to say that it stores energy, and will be able to restore it quickly if ever there is a consumption peak on one of the pedals.

About the diode, it will protect the power supply if the wrong input block is connected, with a reversed polarity.

assemble the 24v in bag

Here is the list of components that you must have in this bag :

We will continue considering that you have read the different blog articles. I’m still going to make a reminder about the delicate components and we’ll have to avoid that you solder them the wrong direction.

In this bag you have a diode and an electrolytic capacitor. For the capa, the + is drawn on the PCB and it corresponds with the longest leg. For the diode, there is a grey ring drawn near one of the legs. The same ring is shown on the PCB.

We will start by soldering these 2 components, then the 2 white connectors. But not the pins! It should look like this:

Once it’ s done, we will test it, to see if everything works. Take your 24V power supply, and plug it into one of the 2 white connectors. Then check the voltage between the left and right pads with a multimeter: you should have around 24V.

If it’s good we move on to the next step!

the supply pcb

A little more components, but it’s still relatively simple!

On the left, you can see the pins on which the 24V DC filtered by the 24V IN PCB comes in.

Then there is a first stage, with a resettable fuse. That is to say if you draw too much current with your pedals (more than 200mA), it will heat up and make an open circuit. But the advantage is that once it has cooled down, the contact is done again, so you won’t have to change it if your power supply has warmed up! Then a diode that will protect again against polarity inversion, this time if you plug your SUPPLY PCB upside down on the 24V IN PCB.

In the second stage, there is once again a filter, which will also lower the voltage a little before reaching the next stage.

Finally, there is the most important part, the voltage regulator! This component lowers and regulates the voltage to a certain value, regardless of the input voltage, by removing the excess in the form of heat. This is the simplest way to make a stable power supply, and it has proven itself for a long time!

Finally, we find the 2 pedal outputs on the right (the black connectors), with diodes in parallel that will protect the PCB if someone has fun getting 9V through an output. We thought about everything! We put 3 of them to divide the current, so as not to make them burn.

assemble the supply bag

Once again we check that you have all the components. In addition to the SUPPLY bag, you must have another small 9, 12 or 18V bag. This bag contains the 3 components that change according to the voltage you want at the output. We are going to assemble a 9V PCB together, and we will explain to you the changes you need to make if you want a 12 or 18V PCB.

We start with the thermo pad. It is necessary to cover it with tin, but without making a big block either!

Then we will solder all the components, except the connectors and pins. Pay attention to the direction of the electrolytic capas and diodes!

Finally, we solder the 2 DC jacks, then we cut the extremity of the legs which exceed, otherwise they will interfere with the next PCB.

And we stop here, you have made your first SUPPLY PCB! Now we’re going to test it.

testing the first supply pcb

We’ll test your first SUPPLY PCB to be sure that you haven’t made any mistakes before moving on to the others! For that, we will take the 24V IN PCB, and screw 4x 12mm spacers (the longest ones). You have to put them in the middle holes on the bottom side, and in 2 of the exterior holes on the top side. Then we screw them with the nuts. As on the picture !

Then you will take 2 male and 2 female pins and connect them together. Then insert them in the external pads of the 24V IN PCB, and screw the SUPPLY PCB on top to hold them, with 2 other spacers.

You just have to solder the pins! It’s much easier to do it that way, rather than soldering them at each step.

Once it’ s done, we can test the PCB! Connect the 24V power supply to the 24V IN PCB, and measure on the pins of the outputs that you have 9V (or the desired voltage if you have made a 12 or 18V PCB).

If it works, congratulations! We will be able to continue with the other SUPPLY PCBs. You can solder them all, but without putting the pins! It will be easier to do it at the end by assembling the power supply. And it will avoid you to make a mistake because there is an alternance to respect.

Normally you have 3 left, if you only want 9V you just have to repeat the same steps for all the other PCBs. If you have a 12 or 18V PCB, it’s the same, just be careful not to mix the components of the 9, 12 and 18V bags, and respect this table:

the 24v thru pcb

We finish with the simplest PCB, the 24V THRU!

The 24V comes from the 24V IN PCB through the left connectors, then comes out through the 2 right connectors (the white connectors). This allows you to have an output to power a 2nd Anasounds or FX Teacher power supply, but not a pedal!

There is always a protection diode, if you ever plug a power supply into this output.

assemble the 24v thru bag

We start the last bag!

You have only 3 components to solder: the diode and the 2 white connectors. Once again you keep the pins aside.

Is it done? Then we move on to the assembly of the power supply!

assembly

We will take the first SUPPLY PCB that we have fully assembled and tested. We remove the 24V IN PCB if it is still screwed, to access the pin pads. Then we connect 2 male and female pins, we take the next SUPPLY card, we screw it to the first one with the spacers, and we solder! The pins must alternate on the inner and outer pads of each new PCB, as shown in the picture.

We continue like this until the last SUPPLY PCB, and we go to the 24V THRU PCB.

On the 24V THRU, we will screw 2x 6mm spacers (the shortest) on the bottom side on the same external holes as the 24V IN (not in the middle). Then, we start again one last time! We put the male and female connectors, screw the 24V THRU PCB to the last SUPPLY PCB, and this time we fix it with 2 screws.

We’re getting there! All you have to do now is to mounting all the PCB again, screwing the spacers between each card and finishing with the 24V IN. Normally, you should still have a few male and female pins left. You can solder them on the 24V IN and 24V THRU PCB. This will allow you not to be embarrassed about the alternation of the pins if you decide to add an odd number of SUPPLY PCBs.

We do a last complete test to make sure that each PCB works correctly, and we can screw the brackets on each side.

your power supply is ready!

And here we go, you’ve made a custom power supply for your pedalboard! With this, we guarantee you the best performance! We did a lot of tests to make sure that this power supply doesn’t let any noise pass through.

You’ll be able to power most of the pedals on the market. And if you ever need more current for a pedal, you can always put a Y-cable. And if that’s still not enough, you can turn to our Anasounds K+ power supply, which can deliver up to 1A per output!

We hope you liked this kit! If you have any questions, feedback, or if you have any problems with the kit’s realization, it’s below in the comments section. We will answer with pleasure!