lm4780 Class A headphone amp

jaudio · 17th November 2008, 01:58 PM

I got a bunch of lm4780 in a trade,now I'm trying to find something to to with them. Because of the small"est" heat transfer area,I want to stay away from anything high powered,so a headphone amp comes to mind.
I want to make it fairly simple,maybe a 4780 in the feedback loop of a smaller op amp(class A biased) or maybe run just the 4780 into class A and deal with the high gain some other way.

Any Ideas would be helpful.

Redshift187 · 17th November 2008, 04:41 PM

The heat isn't as much of an issue as you would think for "normal" music listening. I have an amp that consists of a pair of LM4780s running in bridged mode at 25V (approximately 100W each). Both channels are sharing a heatsink mounted inside my enclosure and cooled without a fan, and it doesn't change temperature noticeably between idle and "normal" listening levels (about 40 C).

jaudio · 17th November 2008, 06:36 PM

Redshift187

What size are your heatsinks? So,a class A headphone amp should do fine with a small heatsink.

I tried a google search but I got nothing.

Redshift187 · 17th November 2008, 08:59 PM

It's about 5cm x 5cm x 20cm. There are only about 25 fins.

17th November 2008, 01:58 PM	#1
jaudio diyAudio Member Join Date: Oct 2004	lm4780 Class A headphone amp I got a bunch of lm4780 in a trade,now I'm trying to find something to to with them. Because of the small"est" heat transfer area,I want to stay away from anything high powered,so a headphone amp comes to mind. I want to make it fairly simple,maybe a 4780 in the feedback loop of a smaller op amp(class A biased) or maybe run just the 4780 into class A and deal with the high gain some other way. Any Ideas would be helpful.

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17th November 2008, 04:41 PM	#2
Redshift187 diyAudio Member Join Date: Aug 2008	The heat isn't as much of an issue as you would think for "normal" music listening. I have an amp that consists of a pair of LM4780s running in bridged mode at 25V (approximately 100W each). Both channels are sharing a heatsink mounted inside my enclosure and cooled without a fan, and it doesn't change temperature noticeably between idle and "normal" listening levels (about 40 C).

17th November 2008, 06:36 PM	#3
jaudio diyAudio Member Join Date: Oct 2004	Redshift187 What size are your heatsinks? So,a class A headphone amp should do fine with a small heatsink. I tried a google search but I got nothing.

17th November 2008, 08:59 PM	#4
Redshift187 diyAudio Member Join Date: Aug 2008	It's about 5cm x 5cm x 20cm. There are only about 25 fins.

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