Fiio E3 power supply

November 25, 2008 at 10:17 pm (Uncategorized)

I really like my E3, it gives my HD555 a much needed bass boost… But, it eats loads and loads of batteries, so i decided to make a power supply for it, but I also wanted to keep case intact, so i can still use it with batteries. So I made a power supply that can go into battery compartment. It is based around LP2950 LDO 3.3 V voltage regulator. I decided to go for the 3.3V since the op amp in the hart of Fiio is made for 1.2-3.5V. The whole thing, is in my case powered from USB, but you can connect it to any voltage up to 30V. Here is how it turned out:


Note that the whole thing fits into battery compartment…



Here is the ultra simple schematic…


And here is the simple board layout, note that it is created on piece of proto board I had laying around. Sorry for a bit poor graphics, i guess i’m just to lazy  to start illustrator to draw it better (so I drew it in eagle 🙂 ):


You can of course use any other 1.2 – 3.3 voltage regulator with same pinout (a lm317 in to-92 package, perhaps)…

The masterpiece works :). There is no audible noise, hum or anything else that is not suposed to be there and the amplified sound is exactly the same as before. Regulator emits little to no heat and op amp remains as cool as before, so there is no worries of destroying it. However, when I pluged it into my laptop (insted of my PC), certian noise was audible (probably due it’s poor voltage regualtion, and digital – analog ground separation), so i also made a veresion that is powerd from old Nokia charger, it of course also works just as well…

If you have any questions, feel free to ask…


1 Comment

  1. Flax said,

    Hey, your page here came up in a google search. I just wanted to ask, do you happen to know what type of opamp is used in the Fiio E3? Some say it might be the model LM4917, but it’s unconfirmed.

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