Portable headphone amplifier project!

[Inocybe]

Hi,

I would like to make a portable headphone amplifier.

The thing that would seperate this from other headphone amps is that it would be much smaller. It may not have the power to drive large (high Ohm) headphones, but enough to drive smaller ones loud and with control.

Why? The amps in many portable electronics is often very poor and weak (notebooks, mobiles, mp3-players ++).

This is the features that I want it to have:

- 3.5mm in stereo plug (with short chord)
- 3.5mm out stereo jack (internal)
- Quality 1.5V stereo up-amp producing high output (20mW/32Ohm+?)
- On/off switch
- Led (power on)
- Power source: 1 x AA
- Small case

If possible:

- Volume control (could be in steps)
- 5/7/10 Band EQ or other kind of adjustable tone control

My idea was to have it totally analogue (digital would be more difficult, I guess). No splitter to save battery (just one jack).

The volume should mainly be adjusted with the source device, but there should (maybe) be a possability to adjust the volume on the amplifier also. This because of adjusting it to the source volume and/or save battery. The goel is to limit the source volume just beneath clipping/distortion/loss-of-control point.

It would be great if a EQ or adjustable tonecontrol could be included. Many devices have no adjustable EQ, or it is quite bad. The source device could then be set in a "flat" position.

The casing should be small enough to be hanging loose, just connected to the jack and plug. With two AA batteries, it suddenly becomes more heavy.

Is it possible to run it on a single AA battery? I have an old iRiver iFP-799 MP3-player with quite good soundquality and with a good amplifier (2x18mW/16 Ohm). The single AA battery last 40 hours. It also uses power on the screen and other things(!). So yes, I think it would be quite possible.

Here is a commersial headphone amp manufacturar:
http://www.boostaroo.com/
They have splitters, making them use more power. They use two AA batteries (heavy) or two AAAA batteries (unpractical). Also, no volume or tone controls.

Please note that I am an electronic novice! I would be happy to get any feedback on this (like part suggestions). So, what do you think?

Thanks

[TerryO]

Originally posted by Inocybe
Hi,

I would like to make a portable headphone amplifier.

The thing that would seperate this from other headphone amps is that it would be much smaller. It may not have the power to drive large (high Ohm) headphones, but enough to drive smaller ones loud and with control.

Why? The amps in many portable electronics is often very poor and weak (notebooks, mobiles, mp3-players ++).

This is the features that I want it to have:

- 3.5mm in stereo plug (with short chord)
- 3.5mm out stereo jack (internal)
- Quality 1.5V stereo up-amp producing high output (20mW/32Ohm+?)
- On/off switch
- Led (power on)
- Power source: 1 x AA
- Small case

If possible:

- Volume control (could be in steps)
- 5/7/10 Band EQ or other kind of adjustable tone control

My idea was to have it totally analogue (digital would be more difficult, I guess). No splitter to save battery (just one jack).

The volume should mainly be adjusted with the source device, but there should (maybe) be a possability to adjust the volume on the amplifier also. This because of adjusting it to the source volume and/or save battery. The goel is to limit the source volume just beneath clipping/distortion/loss-of-control point.

It would be great if a EQ or adjustable tonecontrol could be included. Many devices have no adjustable EQ, or it is quite bad. The source device could then be set in a "flat" position.

The casing should be small enough to be hanging loose, just connected to the jack and plug. With two AA batteries, it suddenly becomes more heavy.

Is it possible to run it on a single AA battery? I have an old iRiver iFP-799 MP3-player with quite good soundquality and with a good amplifier (2x18mW/16 Ohm). The single AA battery last 40 hours. It also uses power on the screen and other things(!). So yes, I think it would be quite possible.

Here is a commersial headphone amp manufacturar:
http://www.boostaroo.com/
They have splitters, making them use more power. They use two AA batteries (heavy) or two AAAA batteries (unpractical). Also, no volume or tone controls.

Please note that I am an electronic novice! I would be happy to get any feedback on this (like part suggestions). So, what do you think?

Thanks

Ino,

Here's what you should start with:

http://headwize.com/ubb/forumdisplay.php?fnum=3


Great forum as well.

Best Regards,
TerryO

[Nordic]

Mini Ipod headphone amp DIY project