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How to Modify SMPS Output Voltage

I’ve got a number of iFi iPower and iPowerX power supplies with factory set voltages of 5V, 12, and 15V. I’m tying to power two devices that require 3.6V and 7.6V. Currently I am using some cheap store bought voltage regulators to take the iFi 12V power supplies down to the desired voltages. I got to thinking that if I could modify the iFi output voltages to the desired voltages, then I wouldn’t need the cheap voltage regulators - fewer lower quality devices in the power chain should improve sound quality. Does anyone know how to do this? I contacted iFi and they said their devices aren’t adjustable nor will they sell me custom voltage units. On some power supplies, it’s as easy as opening the device and adjusting a pot. In other cases, you can switch out a resistor to modify the voltage. I’m okay with voiding the warranty. Does anyone know if this can be done and if so, how to do it? Thank you.

mkgus
erik_squires
16,780 posts
 

DIYaudio is a better source for these types of questions.

What exactly are the devices you are trying to power? They may be OK with slightly higher input voltages.

Of course a cheap solution is a resistive voltage divider. I’m sure you can find calculators online that let you take into account the device current.

If you are willing to take things apart then build your own linear power supply.

mkgus's avatar
mkgus OP
324 posts
 

I’m trying to power a Sony PlayStation 1. The 7.6V is for the motor and the 3.6V is for the chips. I tried using 5V on the chips but the PS1 wouldn’t boot properly. 
 

Concerning using a simple resistive voltage divider, I have learned that there are a number of issues with it such as poor voltage regulation under load. However, if I have a decent power supply directly upstream of that, does that issue go away?

erik_squires
16,780 posts
 

Why are you getting so expensive / exotic with these supplies?  An off the shelf wall wart would be $30 or less.  You don't need super low noise supplies.

You are right.  A VR would be a much better solution than a R divider, but depends on current draws. 

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