Buffer headphone amp

percy · 6th March 2006, 08:55 PM

Are there any headphone amp designs that use only a buffer opamp ? Just a standalone buffer.
All I need is something to provide high impedance to the source and boost the output current high enough for a typical 32ohm heaphone, ofcourse low output impedance.

cetoole · 8th March 2006, 07:50 AM

Not quite what you asked for, but the Szekeres might be a good choice, Class A mosfet buffer.
http://headwize.com/projects/showfil...szeke1_prj.htm

endia · 8th March 2006, 08:45 PM

maybe this one is what you're looking for;
A Buffered Headphone Driver
http://headwize.com/projects/showfil...awliw1_prj.htm

lineup · 8th March 2006, 09:53 PM

Quote:

Originally posted by percy
Are there any headphone amp designs that use only a buffer opamp ?
Just a standalone buffer.
All I need is something to provide high impedance to the source
and boost the output current high enough for a typical 32ohm headphone,
of course low output impedance.

A good option is to use a dual Op-Amp, like for example OPA2134 (good quality/price)
and parallel the dual to give double current output.
Will power most every 32 Ohm headphones, more than enough.

At Raymond's DIY Audio Pages I found such a project.
Pictures and schematics, including power supply.
Very nice documentation indeed!
He has also two other headphone amplifiers and more good audio projects.

Quote:

Opamp Headphone Amplifier

This is an headphone amplifier, based on the OPA2134 from Burr-Brown.
Two opamps are used, with one half of each buffering the output of the other half
for increased current capability.

A guy from Finland has built Raymond's project and documented this with images.
He uses PCB he made himself.
http://www.kolumbus.fi/antti.penttala/ele/headamp/

This is schematic:

He uses 100k/10k gain=11.
This is changed easily.
Removing 10k resistor (R3) gives gain=1. (Unity gain buffer)
Making R3=100k gives gain=2.

Amplifier image:

The small heatsinks are for LM317 LM337 voltage regulator chips.

lineup · 8th March 2006, 09:58 PM

This is a picture of guy from Finland's amplifier a la Raymond.
From link in post above.
You see the two OPA2134 and components placement here:

tlmadsen · 9th March 2006, 07:49 AM

Percy

Try the BUF634T from BB/Texas

Have fun

Thomas

percy · 9th March 2006, 04:43 PM

I have seen BUF634 being used in a few diy headphone amps as an output stage preceeded by another opamp but have yet to come across one by itself.

thanks all for the project links. I will check them out.

karahara · 9th March 2006, 04:53 PM

Look at the LT1010, imo a very good choice for that app.

percy · 12th March 2006, 04:32 AM

or the LT1210 maybe ? anyone tried it yet ?

ChUmI · 12th March 2006, 07:07 AM

percy,

I used LT1210 and it works like a best sounding chip headphone amp in my collection

My Sony MDR-F1 headphones have only 12 Ohm and are driven perfectly - so deep bass I never heard form a small chip

6th March 2006, 08:55 PM	#1
percy diyAudio Member Join Date: Apr 2004 Location: MN	Buffer headphone amp Are there any headphone amp designs that use only a buffer opamp ? Just a standalone buffer. All I need is something to provide high impedance to the source and boost the output current high enough for a typical 32ohm heaphone, ofcourse low output impedance.

8th March 2006, 09:58 PM	#5
lineup diyAudio Member Join Date: Dec 2005 Location: the north	This is a picture of guy from Finland's amplifier a la Raymond. From link in post above. You see the two OPA2134 and components placement here: __________________ lineup

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8th March 2006, 07:50 AM	#2
cetoole diyAudio Member Join Date: Mar 2005 Location: Maryland, USA	Not quite what you asked for, but the Szekeres might be a good choice, Class A mosfet buffer. http://headwize.com/projects/showfil...szeke1_prj.htm

8th March 2006, 08:45 PM	#3
endia diyAudio Member Join Date: Sep 2004 Location: istanbul	maybe this one is what you're looking for; A Buffered Headphone Driver http://headwize.com/projects/showfil...awliw1_prj.htm

9th March 2006, 07:49 AM	#6
tlmadsen diyAudio Member Join Date: Aug 2003 Location: Roskilde - The vikingships	Percy Try the BUF634T from BB/Texas Have fun Thomas

9th March 2006, 04:43 PM	#7
percy diyAudio Member Join Date: Apr 2004 Location: MN	I have seen BUF634 being used in a few diy headphone amps as an output stage preceeded by another opamp but have yet to come across one by itself. thanks all for the project links. I will check them out.

9th March 2006, 04:53 PM	#8
karahara diyAudio Member Join Date: Dec 2003 Location: Germany - Bavaria	Look at the LT1010, imo a very good choice for that app.

12th March 2006, 04:32 AM	#9
percy diyAudio Member Join Date: Apr 2004 Location: MN	or the LT1210 maybe ? anyone tried it yet ?

12th March 2006, 07:07 AM	#10
ChUmI diyAudio Member Join Date: Dec 2004 Location: Stuttgart / Germany	percy, I used LT1210 and it works like a best sounding chip headphone amp in my collection My Sony MDR-F1 headphones have only 12 Ohm and are driven perfectly - so deep bass I never heard form a small chip

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