Newbie Guidance...

[li_gangyi]

Actually I was wondering why he would want to use tantulams...seems you could use BGs and stuff here and get better results...I would recommend he check Nuuk's pages for some sugestions while retaining the use of the 3886...whihc has high current capability then the 3875...but you still have the mute pin to worry about...I did build an 3886 amp only to wonder why there was no sound...then I realised I never connected anything to the mute pin...stupid me...

[Paprika]

Well how does the mute pin work? I thought it muted the sound when grounded or when one would raise a + Signal to it.

See if the mute feature is out to get me then I won't get a chip with a mute feature.


Ugh.... Anyway, If I had to go with something that National Reccomends rather than following the plan layed out by the website, I would follow the 'Typical Application' schematic in the LM3886 datasheet:

http://www.national.com/ds/LM/LM3886.pdf

I'm sure it would work, it's just a matter of moving the schematic to Eagle and then designing the board

[Paprika]

Sorry, for some reason I wasn't able to EDIT my last reply so i had to post another one here.

My problem with using that schematic right now is the fact that Eagle doesn't have the LM3886 CHIP in it's component library, let alone any equivilant that i know of (none). I am too sleepy and don't have the enthusiasm to make a custom chip, so I am asking for some advice what I should do.

I was thinking a second ago about doing it the Protoboard method but I believe with high voltage applications using protoboards for primary use isn't a good ideal - I don't want to hand-wire everything togethe like a ghetto rig either, I could do it that way, but I'd rathewr have something cleaner and more presentable...

[Peter Daniel]

I would actually recommend doing it p2p. When done properly it doesn't neccessarily have to look like "like a ghetto rig either"
http://www.diyaudio.com/forums/showt...578#post260578

[Easyamp]

I made the lm3875 part for eagle, if you want it let me know I''ll email you the library.

I have made amps out of both the 3886 and 3875 and prefer the 3875 over 3886 in quality of sound and the lack of the mute function. Over both of these though I would take an OPA541 any day, they are more expensive but are very enjoyable to listen to.

You can look at an amp I'm toying with currently http://www.easyamp.com/img/lm3875/amp-top.jpg
http://www.easyamp.com/img/lm3875/amp-bottom.jpg



The amps are on the same board but are independent. If you would like a schematic or parts list let me know.

[Paprika]

Hey cool, I'd REALLY appreciate all three.. lol Those being the parts list, schematic and lm3875 part for eagle. I'd ReALLY appreciate it.

Well... umm.. if you can do that, just email them all in a ZIP file to Paprika_OREGONLEADER@teen-moods.net

.... REMOVE the "_OREGONLEADER" mess, just an anti-spam technique.

[Easyamp]

Ok, I'll send it to you or you can go to www.easyamp.com/lm3875

You may need to check the trace size on a few I think some of the ground traces should be larger but it does work.

I'm not sure what if anything else you need other the library to get the part in to work in eagle, like symbols or something. Try it and let me know.

[Paprika]

ahhh ok, I see. Thanks. When I said schematic I meant like your eagle schematic & board files if you could I would greatly appreciate it!

I got the library to work too. Thanks for all your help!

[Easyamp]

Oh, you want the actual eagle created files, I'll post them on my site.

[Paprika]

ok, thanks - much appreciated.