LME49600/LME49740 Headphome Amp

theAnonymous1 · 19th September 2008, 08:32 PM

I haven't seen any LME49600 headphone amps built around here so I figured I would post mine. It's the basic circuit from the datasheet with minor adjustments for parts on hand.

It sounds great with an absolutely pure black background. It's impossible to tell it's even on with the pot turned all the way down.

I built it small for portable battery powered use, but the idle current is ~47ma so I'm not so sure how good that's going to work out.

When I have the time I plan on building the regulators in the datasheet as well.

theAnonymous1 · 19th September 2008, 09:47 PM

Headphome.

jackinnj · 19th September 2008, 10:47 PM

Quote:

Originally posted by theAnonymous1
I built it small for portable battery powered use, but the idle current is ~47ma so I'm not so sure how good that's going to work out.

Maybe a motor-cycle lead acid cell

Did you bandwidth the LME49600? The LME497400 is a bit of a piggy when it comes to idle as well.

fwiw, I have my samples, just haven't got to play around with it yet.

theAnonymous1 · 19th September 2008, 10:54 PM

Yes, I connected the bandwidth pin to VEE because that's how the schematic has it. I tried lifting both the pins and the idle current went from ~47ma to ~35ma. Does a headphone amp really need 180MHz bandwidth anyway?

jackinnj · 19th September 2008, 11:40 PM

Quote:

Originally posted by theAnonymous1
Does a headphone amp really need 180MHz bandwidth anyway?

I think that some writers at Stereophile would find this a necessity.

theAnonymous1 · 19th September 2008, 11:55 PM

Quote:

Originally posted by jackinnj
I think that some writers at Stereophile would find this a necessity.

And the sight of the tantalum rail filtering caps on my board would probably make them lose their lunch.

jackinnj · 20th September 2008, 12:51 AM

I have sworn off SMT electrolytic caps, Al or whatever -- for DIY projects they are too much a nuisance.

TzeYang · 20th September 2008, 01:14 AM

I think this amplifier is incredible.

How did you split the rails? Are those two huge ICs BUF634?

EDIT: Did you etch the board yourself? The boards looks very nice.

theAnonymous1 · 20th September 2008, 02:12 AM

Quote:

Originally posted by TzeYang
I think this amplifier is incredible.

How did you split the rails? Are those two huge ICs BUF634?

EDIT: Did you etch the board yourself? The boards looks very nice.

Thank you.

I was using a +/-15v test supply I have; there isn't any rail splitting or buffered ground stuff happening on the board.

The two huge ICs are the LME49600 buffers. I think I read somewhere they are very close if not the same as BUF634.

I etched the board, but to be honest I think it turned out like c**p. I had already been up for 22hrs when I started on it and it shows. Then my dremel tools bearings decided to go bad making the drilling a PITA with little bits of carbide flying everywhere, so most of the holes are off center.

Oh well, I guess it's function not form that really matters, and it definitely functions.

TzeYang · 20th September 2008, 02:19 AM

^Self-etched double layer boards tend to have HIGH failure rate. I'm surprised it turned out so reasonably well for your case.

I'm still too pussy to do it though. Actually I'm just too poor to afford failure.

19th September 2008, 08:32 PM	#1
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	LME49600/LME49740 Headphome Amp I haven't seen any LME49600 headphone amps built around here so I figured I would post mine. It's the basic circuit from the datasheet with minor adjustments for parts on hand. It sounds great with an absolutely pure black background. It's impossible to tell it's even on with the pot turned all the way down. I built it small for portable battery powered use, but the idle current is ~47ma so I'm not so sure how good that's going to work out. When I have the time I plan on building the regulators in the datasheet as well. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

19th September 2008, 09:47 PM	#2
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Re: LME49600/LME49740 Headphome Amp Headphome. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

19th September 2008, 10:54 PM	#4
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Yes, I connected the bandwidth pin to VEE because that's how the schematic has it. I tried lifting both the pins and the idle current went from ~47ma to ~35ma. Does a headphone amp really need 180MHz bandwidth anyway? __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

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20th September 2008, 12:51 AM	#7
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	I have sworn off SMT electrolytic caps, Al or whatever -- for DIY projects they are too much a nuisance.

20th September 2008, 01:14 AM	#8
TzeYang diyAudio Member Join Date: Jun 2006	I think this amplifier is incredible. How did you split the rails? Are those two huge ICs BUF634? EDIT: Did you etch the board yourself? The boards looks very nice.

20th September 2008, 02:19 AM	#10
TzeYang diyAudio Member Join Date: Jun 2006	^Self-etched double layer boards tend to have HIGH failure rate. I'm surprised it turned out so reasonably well for your case. I'm still too pussy to do it though. Actually I'm just too poor to afford failure.

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