Portable Headphone Amp - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th July 2004, 12:04 AM   #1
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
Default Portable Headphone Amp

Hello,

I got a new MP3 player and its mighty quiet. Too quiet. I need to build a portable headphone amplifier for it and my Grado SR 80s (and occasionally my Senn MX-500 earbuds which are even quieter).

I'd really like to design and build an amplifier, but I need recommendations for chips to base it off of. I did some Op Amp work a while ago in school, I still have my old texts, but I need some silicon to start from. If there's pressing need to go away from simple to do Op Amp systems, please elaborate. I'm listening.

Efficiency is a concern. Size would be nice.

Sound quality is semi-nice, but I dont plan on taking extrodinary measures in this project, given that my mp3 player itself doesnt produce the best sound. I'm hoping that it provides good sound at lower volumes, produces less clipping, and that a good pocket amplifier will give me better volume with better sound.

I'm assuming I'll need a very efficient dc-dc converter as well. my mp3 player uses a single aaa battery. i'm probably going to rip it out of its shell and use an aa battery, maybe go dual aa if the amp warrants it.

I've been checking HeadWize, but most of that seems to be non-portable systems. My searching here has resulted with a similar lack of starting place, although I have found a number of interesting in depth discussions. I believe with a starting place I'll be able to do far better research. Thank you for your assistance.

What silicon to use?
thanks
myren
  Reply With Quote
Old 13th July 2004, 12:20 AM   #2
diyAudio Member
 
Join Date: Nov 2000
Quote:
I've been checking HeadWize, but most of that seems to be non-portable systems.
the Chu Moy Pocket Amp is a portable design and goes into a lot of detail about the design.

Another good portable amp sit is

http://tangentsoft.net/audio/

and a links page that is more or less headphone amp specific :

http://www4.head-fi.org/forums/showthread.php?t=21563
  Reply With Quote
Old 13th July 2004, 02:57 AM   #3
diyAudio Member
 
Algar_emi's Avatar
 
Join Date: Oct 2002
Location: Canada, Qc
Check www.headwize.com, projects section:
http://headwize.com/projects/index.htm

The best reference for headphone amps on the net.

Bye...
  Reply With Quote
Old 13th July 2004, 04:43 AM   #4
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Texas Instruments has a new IC (it's surface-mount) which has high current drive just for this purpose. i was sent some samples, but have not yet burned boards...claimed distortion is in the thousandths of a percent.
  Reply With Quote
Old 13th July 2004, 08:54 AM   #5
Nisbeth is offline Nisbeth  Denmark
diyAudio Member
 
Nisbeth's Avatar
 
Join Date: Jan 2001
Location: Denmark
Start out doing a simple Cmoy amp based on OPA2132/2134. If you like, you can then experiment with different opamps to see what your prefer (commonly used types for headphone amps are OPA(2)227/(2)228, OPA(2)604, OPA627/637, AD8610/8620, AD823, AD843, AD845 and a few others). If you then want something better, then check out one of the designs from the tangentsoft-page linked above or start digging in the headwize archives for something you think looks interesting. Happy building


/U.


PS: The chip jackinnj is referring to is called TPA6120.
  Reply With Quote
Old 13th July 2004, 09:43 PM   #6
diyAudio Member
 
Join Date: Jul 2004
Location: Berlin
Don't you think it'll get too complex with a dc-dc converter? It would increase circuit size, also this could introduce switching noise...

For my tiny portable mic preamp, I'm planning to use those hearing aid batteries (Zinc-Air) which exist in several sizes and the strongest are 11.6mm diameter, 5.4mm thick, 1.4V with over 500mAh!! That's a lot of capacity! And the OPA228 works fine with +- 4.2V, which means two times 3 cells, so 11.6 x 32,4mm.

Of course, you'd better estimate how much current the circuit will consume before choosing the batteries.

Regarding the choice of OP-amps, there are a lot, but do you want to build surface-mount or conventional style? Some of the newer OP-amps only exist for surface mounting.

Cheers
Dominique

Edit: I'm not sure if I understand you right:
You want to build the amp in a tiny extra box, do you?
  Reply With Quote
Old 13th July 2004, 10:04 PM   #7
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
Default Re: Portable Headphone Amp

Quote:
Originally posted by Myren
Hello,

Efficiency is a concern. Size would be nice.

Sound quality is semi-nice, but I dont plan on taking extrodinary measures in this project, given that my mp3 player itself doesnt produce the best sound. I'm hoping that it provides good sound at lower volumes, produces less clipping, and that a good pocket amplifier will give me better volume with better sound.

I'm assuming I'll need a very efficient dc-dc converter as well. my mp3 player uses a single aaa battery. i'm probably going to rip it out of its shell and use an aa battery, maybe go dual aa if the amp warrants it.

What silicon to use?
thanks
myren
I have been using a TPS61020DRCR STEPUP with a effiency of 96% for a handheld design (Cannot tell you about it... Brandnew hardware for another industry).. And it works like a charm...

It puts out 5VDC from a single AAA cell. and it has a battery low detector.

By the way... Size is 42mm*10mm*5mm on a 1.6mm FR4 PCB.
And it is very simpel to use.

The go for opamp's like AD8027/8028 which can run from singlesupply. Deliver 50mA into a load.
And you can control the crossover region of the input stage...
__________________
Mirand Audio amps and Dac's - http://www.mirand-audio.dk
  Reply With Quote
Old 13th July 2004, 10:06 PM   #8
Nisbeth is offline Nisbeth  Denmark
diyAudio Member
 
Nisbeth's Avatar
 
Join Date: Jan 2001
Location: Denmark
No noise issues?


/U.
  Reply With Quote
Old 13th July 2004, 10:31 PM   #9
sonnya is offline sonnya  Denmark
diyAudio Member
 
sonnya's Avatar
 
Join Date: Oct 2001
Location: Denmark
from the SMPS??

i use 6.2uH inductors from panasonic which is shielded.
Also i use an LC output filter. so i have like 10mVpp at 700KHz.

it is placed in close proximity to a LF trasnponder reader, and this runs with no problem, with no reduction in reading distance.

And they are sensitive to radiated noise.
__________________
Mirand Audio amps and Dac's - http://www.mirand-audio.dk
  Reply With Quote
Old 14th July 2004, 02:06 AM   #10
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
Default thanks

thanks all!

yes, to confirm, i'm looking to build a small single unit portable head phone amplifier. size is an object, and i'm coincidentally quite eager to start some surface mount work.

one or two aa batteries are my ideal power source: i have a bunch of 2200 mah double a rechargables I payed a mint for, but work excellently. i presume most amplifieres will require a +/- voltage. dc-dc convertors will get me this voltage split, i presume. what other techniques are there? i suppose dual battery is another option.

out of a morbid sense of curiosity, how different are the parameters to turn a headphone post-amp into a mic pre-amp? it occurs to me i have a microphone in need as well.

I'm with you guys through everything else, I have absolutely no idea what any of this means:
Quote:
it is placed in close proximity to a LF trasnponder reader, and this runs with no problem, with no reduction in reading distance.
thanks
Myren
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Recommendations for portable headphone amp? Spasticteapot Headphone Systems 0 1st September 2008 04:01 AM
Buying Portable Headphone Amp Audio.Spec1 Swap Meet 1 9th January 2008 04:23 PM
Portable headphone amp. cliffforrest Headphone Systems 4 27th January 2007 03:15 PM
META42 portable headphone amp morsel Headphone Systems 1 13th June 2002 05:40 AM


New To Site? Need Help?

All times are GMT. The time now is 01:42 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2