Lm1876

Bone · 26th November 2008, 05:58 PM

Hi everyone,

Has anyone used this chip to build a stereo amp?
Is it 2 x LM1875 in one package? It has similarities.

If you have used it how does it sound?
and does anyone have a PCB layout they are willing to share please?

Thanks and regards Tony.

pacificblue · 26th November 2008, 07:58 PM

I use one for my PC speakers.

It is not 2 x LM1875 in one package. It has similar power rating, but the equivalent schematic looks more advanced, as do the specs.

How does it sound? That is a difficult question, because it depends on the application and the speakers.

When I finished it, I compared it to my living room amp (of course). That was quite unfair, because my LM1876 is supposed to be used for near-field listening at low listening levels. So it has a very small power supply that limits its output to about 2 x 5 W into 8 Ohm.

At first the LM1876 showed more or less what people discuss a lot here, a slight lack of punch. That was with 1000 µF per rail. After increasing that to 6800 µF there is nothing missing anymore.

What strikes me most is that it seems to give rhythm to the music. Now what does that mean? While my other amplifier makes you want to sit still and listen, the LM1876 makes you want to get up and move. I verified this with several different speakers, but have no idea, where that effect comes from. Other than that there is nothing unusual about it. The frequency response is as flat as can be, THD is low, accuracy is high, power output is reasonable, staging is credible. A recommendable IC.

My PCB files got lost, when I got a new PC. Somehow missed them, when I copied everything else. Anyhow it was not based on a complete and well-designed schematic that would have been good for sharing. Just a quick-'n'-dirty DC coupled amp with PSU on board.
But how about the evaluation board from National themselves?

Regards
David

e_fortier · 26th November 2008, 10:44 PM

Does the 1875 makes you want to get up and move...

I just bought a kit from e-bay so I was wondering.

TIA,
Eric

pacificblue · 27th November 2008, 07:59 AM

Sorry, I have no personal experience with the LM1875.

santik · 16th February 2011, 11:40 AM

pacificblue, you should share your schematics for us to see...

AndrewT · 16th February 2011, 12:38 PM

Quote:

Originally Posted by pacificblue

I have no personal experience with the LM1875.

Quote:

Originally Posted by santik

pacificblue, you should share your schematics

are you asking the possible or the impossible?

santik · 17th February 2011, 10:43 AM

oh, I meant LM1876.

pacificblue · 17th February 2011, 06:49 PM

@santik,

you already got an answer to your PM. The last chapter of post #2 is still valid.

santik · 18th February 2011, 02:32 PM

thanks for your reply pacificblue.

I will go on designing my amp... if I have any questions I would post it here and PM you...

thanks

26th November 2008, 05:58 PM	#1
Bone diyAudio Member Join Date: Jun 2004 Location: Dorset, UK	Lm1876 Hi everyone, Has anyone used this chip to build a stereo amp? Is it 2 x LM1875 in one package? It has similarities. If you have used it how does it sound? and does anyone have a PCB layout they are willing to share please? Thanks and regards Tony.

27th November 2008, 07:59 AM	#4
pacificblue diyAudio Member Join Date: May 2008	Sorry, I have no personal experience with the LM1875. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

17th February 2011, 06:49 PM	#8
pacificblue diyAudio Member Join Date: May 2008	@santik, you already got an answer to your PM. The last chapter of post #2 is still valid. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

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26th November 2008, 07:58 PM	#2
pacificblue diyAudio Member Join Date: May 2008	I use one for my PC speakers. It is not 2 x LM1875 in one package. It has similar power rating, but the equivalent schematic looks more advanced, as do the specs. How does it sound? That is a difficult question, because it depends on the application and the speakers. When I finished it, I compared it to my living room amp (of course). That was quite unfair, because my LM1876 is supposed to be used for near-field listening at low listening levels. So it has a very small power supply that limits its output to about 2 x 5 W into 8 Ohm. At first the LM1876 showed more or less what people discuss a lot here, a slight lack of punch. That was with 1000 µF per rail. After increasing that to 6800 µF there is nothing missing anymore. What strikes me most is that it seems to give rhythm to the music. Now what does that mean? While my other amplifier makes you want to sit still and listen, the LM1876 makes you want to get up and move. I verified this with several different speakers, but have no idea, where that effect comes from. Other than that there is nothing unusual about it. The frequency response is as flat as can be, THD is low, accuracy is high, power output is reasonable, staging is credible. A recommendable IC. My PCB files got lost, when I got a new PC. Somehow missed them, when I copied everything else. Anyhow it was not based on a complete and well-designed schematic that would have been good for sharing. Just a quick-'n'-dirty DC coupled amp with PSU on board. But how about the evaluation board from National themselves? Regards David __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

26th November 2008, 10:44 PM	#3
e_fortier diyAudio Member Join Date: May 2001 Location: Montreal	Does the 1875 makes you want to get up and move... I just bought a kit from e-bay so I was wondering. TIA, Eric

16th February 2011, 11:40 AM	#5
santik diyAudio Member Join Date: Feb 2011	pacificblue, you should share your schematics for us to see...

17th February 2011, 10:43 AM	#7
santik diyAudio Member Join Date: Feb 2011	oh, I meant LM1876.

18th February 2011, 02:32 PM	#9
santik diyAudio Member Join Date: Feb 2011	thanks for your reply pacificblue. I will go on designing my amp... if I have any questions I would post it here and PM you... thanks

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