$10 semi-diy 9v battery headphone amp (LM4881)

[TequilaKez]

Just wanted to share the little headphone amp I wired up.
Cheap, portable, easy to solder, and decent quality components so it sounds great.

What you need:

1.$10  http://www.ebay.com.au/itm/2-X-150-mW-Class-AB-Headphone-Amplifier-Board-LM4881-150mW-Stereo-HP-Amp-/121155320773?pt=AU_Bedroom_Furniture&hash=item1c356b7bc5
2. 9V battery clip (a few cents)
3. Canon AV cable.
4. Suitable enclosure of your choice. Sweets tins are good.

I had a spare AV cable so I chose to butcher it and keep it simple but you could easily wire up RCA sockets. I also chose not to use terminal blocks but they're probably a good idea.

There's only a dip switch for low and high gain but I've found the default setting to be the perfect level as is.
You could easily attenuate the input with a pot but I find the ML headphone volume control is enough (devs: a couple a negative gain options might be handy)




Now just need a on/off switch and suitable pocket sized case that could be optionally velcro'd to the tripod.

Specs are not bad either.

Size:76.2 mm (L) x 50.8 mm (W) x 12.1 mm(H) ± 0.2mm
Thermal shutdown protection circuitry
Adjustable gain
Wide power supply range: 8V-24V
Audiophile Quality Sound:
0.025% THD+N @120mWrms 16Ω
0.02% THD+N @75mWrms 32Ω

[PressureFM]

If you want something self-contained and smaller, check out the FiiO E06 portable headphone amplifier.

[TequilaKez]

Nice. 3 x price and a bit more fiddly with extra connections, though I guess you could just solder a 3.5mm plug onto the av cable. Charging via USB is def a nice vibe though!