Battery powered WAV's player with headphone amp...

Hey guys,

So I've got this project where I need to build a battery powered, SD card reading WAV player (not Mp3's... ) with enough power to drive a big headphone...

Right now I'm looking at a raspberry Pi playing WAV's, using a Behringer UCA222 USB and that works, but I was hoping to find a more reliable way... Like dedicated player with headphone amplifier. I'm powering from a 5V power bank because it needs to be rechargeable.

The raspberry gives me the gpio for switches (I need play, stop, next and previous), it plays flac/wav/and some more...

I would appreciate your 2 cents on this project

Why DIY?

There's one point to keep in mind with the Pi: If you plan on using the SD card as storage, it will fail one day. So if you're thinking DIY for reliability, it might be good to look at the Arduino.

Doesn't need to be DIY, but a raspberry pi does everything you'll need... it's a mini computer. An arduino is very basic and it needs a shield to even hold any storage large enough to hold 20 minutes of high quality audio.  But it has crossed my mind... I was hoping some of you have had a similar project where high fidelity audio needs to be played from a storage card into a headphone.  if the SD card fails after let's say 2 months that doesn't mather because it's a first impression kind of project...

basicly it's a a way to bring a new album to a select group of VIP's , they just have to open a box, press play and listen...

Hi Eliani,

Not exactly DIY but any retired Android phone would be able to do that.

Old Sony Xperia phones for example support SD-cards and have built-in good quality headphone amp that happily drives low impedances.

The built-in player supports wav up to 24bit, at 44k1 and 48k.

Grtz Rogy

Rogy said:

Not exactly DIY but any retired Android phone would be able to do that.
Old Sony Xperia phones for example support SD-cards and have built-in good quality headphone amp that happily drives low impedances.
The built-in player supports wav up to 24bit, at 44k1 and 48k.

Click to expand...

I was thinking about that, you can buy an old android phone for peanuts,
you have everything you are looking for there and no work involved.

Why not do that route?

So I've got this project partly running,

I found this Wav playing PCB where you can put in a USB stick and plays decent audio. it has a line-out and I'm using a parallel 5233 head amp to drive my headphones, and it works perfectly... but as soon as I use both PCBs from the same power supply I get strange noises and no sound... 

This is de headamp, it's the last step in a 4 channel summing amp and headphone amplifier I've designed, and it works perfectly... by itself. Do not look at the power connection, it was a picture I took while trying out different setups...



Here is the power step-up board to from 5V to 12V so I've got + and -6V and the schematics of the PSU, it's the same as DIYrecordingequipments PSU and so many others with virtual ground





I run this of a 5V powerbank and it works great!! clean, high gain... round and nice sound!!

when I hook up the Wav player board I get a loud Hum and audio is full distorted


the player board gets the same 12V but it goes trough a 5V regulator

So I managed to get rid of the ground loop Hum by taking the power for the USB player before the step-up... There's no need to step that voltage up and to bring it back down again...

But the audio is still insanely distorted, I guess I should check the voltages going to the opamps...

So after rewiring the power wires, I left the ground unhooked on the player side and that did the trick... Clean sound !!
Thank you guys for all the help!!