Building an isolated power supply
Posted by balazs.bencs on Oct 28, 2019; 1:16pm
URL: http://guitar-fx-layouts.238.s1.nabble.com/Building-an-isolated-power-supply-tp47640.html
Hey folks,
I scratched my head a lot lately because I needed a power supply for my smaller pedalboard and I didn't want to buy a new one because they are so expensive, so I figured that I have to do something DIY.
I really liked the idea of the Gigrig power supply thing, where they have a power supply, distributors and isolators for clean power. Since I had a 12V 1.5A PSU (it was for an old LG TV media player box) in the drawer, I thought I might build an "isolator" similar to the Gigrig one, and I thought I will share with you what I did, so everyone can build one and learn from each other.
So the schem looks like this:
Not a lot to it, but there are a few things I learned to get to building it:
- I had a 12V supply at hand, so I wanted to buy a 12V to 9V converter with isolation, you can change that for whatever PSU you have at home. The GigRig isolators use a Recom RN-0909S DC-DC converter so that you can isolate 9V anywhere in your chain.
- The PCB design was made with that 9V to 9V converter in mind, but there are a ton of others too with the same packaging (DIP8), so look around - what you can buy cheaper is going to determine a lot of things. Mine changed in the process too, because I found a 12V to 9V converter locally way cheaper than online prices (Aimtec AM1PS-1209S-NZ), but had the same packaging and pinout.
- When looking for converters, make sure you have enough power for your needs (110mA for my needs were more than enough), and important to check the switching frequency. Mine was between 100kHz and 300kHz, so way out of audible range.
- The chokes in the schematic came from the datasheet of the converters, I don't think you really have to have those for pedals, but I wanted to try them out, I used SMD inductors - they are easy to solder and not too big. I think one of the boards I just jumpered the inductor after the DC converter and worked and sounded identical to me.
- I saw something similar to C4 in a couple of designs, but I ended up not using it in my build - you can experiment there if it's going to change anything.
Here's the PCB that I quickly drew up with Eagle and ordered a bunch from JLCPCB, they work fine. (oh and I used the EasyEDA online designer tool, which can panelize eagle PCB designs, so I got 5 boards with 4 of these panels - 20 boards for 2$)
Summary: I think these converters are really cool, I think my Klon clone sounds way better - I don't exactly know why, maybe cause of the type of the PSU - this one is switching, my other Palmer isolated PSU is toroidal transformer based. My pedals are working really good with this PSU solution.
If you have an AC-DC adapter somewhere in the garage that is small and can be used for pedals, I think this solution is great and saving electronic devices.
What do you guys think? Let me know your thoughts!
URL: http://guitar-fx-layouts.238.s1.nabble.com/Building-an-isolated-power-supply-tp47640.html
Hey folks,
I scratched my head a lot lately because I needed a power supply for my smaller pedalboard and I didn't want to buy a new one because they are so expensive, so I figured that I have to do something DIY.
I really liked the idea of the Gigrig power supply thing, where they have a power supply, distributors and isolators for clean power. Since I had a 12V 1.5A PSU (it was for an old LG TV media player box) in the drawer, I thought I might build an "isolator" similar to the Gigrig one, and I thought I will share with you what I did, so everyone can build one and learn from each other.
So the schem looks like this:
Not a lot to it, but there are a few things I learned to get to building it:
- I had a 12V supply at hand, so I wanted to buy a 12V to 9V converter with isolation, you can change that for whatever PSU you have at home. The GigRig isolators use a Recom RN-0909S DC-DC converter so that you can isolate 9V anywhere in your chain.
- The PCB design was made with that 9V to 9V converter in mind, but there are a ton of others too with the same packaging (DIP8), so look around - what you can buy cheaper is going to determine a lot of things. Mine changed in the process too, because I found a 12V to 9V converter locally way cheaper than online prices (Aimtec AM1PS-1209S-NZ), but had the same packaging and pinout.
- When looking for converters, make sure you have enough power for your needs (110mA for my needs were more than enough), and important to check the switching frequency. Mine was between 100kHz and 300kHz, so way out of audible range.
- The chokes in the schematic came from the datasheet of the converters, I don't think you really have to have those for pedals, but I wanted to try them out, I used SMD inductors - they are easy to solder and not too big. I think one of the boards I just jumpered the inductor after the DC converter and worked and sounded identical to me.
- I saw something similar to C4 in a couple of designs, but I ended up not using it in my build - you can experiment there if it's going to change anything.
Here's the PCB that I quickly drew up with Eagle and ordered a bunch from JLCPCB, they work fine. (oh and I used the EasyEDA online designer tool, which can panelize eagle PCB designs, so I got 5 boards with 4 of these panels - 20 boards for 2$)
Summary: I think these converters are really cool, I think my Klon clone sounds way better - I don't exactly know why, maybe cause of the type of the PSU - this one is switching, my other Palmer isolated PSU is toroidal transformer based. My pedals are working really good with this PSU solution.
If you have an AC-DC adapter somewhere in the garage that is small and can be used for pedals, I think this solution is great and saving electronic devices.
What do you guys think? Let me know your thoughts!
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