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My LM3875 based chipamp!
http://diyaudioprojects.com/Forum/viewtopic.php?f=10&t=24
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Author:  bsgd [ 09 Jun 2008, 21:28 ]
Post subject:  My LM3875 based chipamp!

Well this is my LM3875 based chip amp!

It's basically a copy of Mark's LM3875 gainclone chip amp.
I used 6800uF caps instead of the 10000uFs and also used an ALPS black beauty as volume pot.
The tranny I got from an old YAMAHA active subwoofer.

This is a great project for anyone willing to get into audio DIY. It's pretty straight forward to build and there's no high voltage to get you into trouble ;) .

Pics:
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Author:  Gio [ 09 Jun 2008, 22:36 ]
Post subject:  Re: My 3875 based chipamp!

Indeed, these gainclones make for a great first DIY amp. They are simple, economical and most important, they really sound great.

How do you like the sound?

Author:  bsgd [ 10 Jun 2008, 07:10 ]
Post subject:  Re: My LM3875 based chipamp!

I would say it sounds simply fantanstic, especially for the total price.

I like better the sound of my OD, but it cost me much, much more. I would say for the price, you can't beat it.

Author:  mwhouston [ 10 Jun 2008, 19:06 ]
Post subject:  Re: My LM3875 based chipamp!

Thats the beauty of a chip amps.Cheap, simple and they sound great no matter how you configure them. This is visually a nice build from the top. I like to think of amp building as art, The amp should be technically correct, look stunning (visual statement) and have a sound to match.

Nice job.

Author:  RiGuy [ 10 Jun 2008, 21:40 ]
Post subject:  Re: My LM3875 based chipamp!

I really like the upside down baking pan. It shouldnt look that good, but it does!

Author:  bsgd [ 11 Jun 2008, 07:44 ]
Post subject:  Re: My LM3875 based chipamp!

mwhouston wrote:
Thats the beauty of a chip amps.Cheap, simple and they sound great no matter how you configure them. This is visually a nice build from the top. I like to think of amp building as art, The amp should be technically correct, look stunning (visual statement) and have a sound to match.

Nice job.




Yes, I agree. Also, here in Brazil amplifiers are very very costly (actually everything here is very exepensive compared to US). A used 80wpc Sony amp here costs around $850, and sounds worse than this chipamp. That's why I'm so into audio DIY now. A tube amp here, for instance, a used 2102 McIntosh amp here runs for about $10.000. Even those chinese Yaqin MC-100b here are around $4.000 :eek: . So, building my own amps is no doubt great, pocket-speaking :mrgreen:

Author:  bsgd [ 11 Jun 2008, 07:45 ]
Post subject:  Re: My LM3875 based chipamp!

RiGuy wrote:
I really like the upside down baking pan. It shouldnt look that good, but it does!



Thank you, I like it too :)

Although right now I'm trying to find a nicer chassis option for my next projects...

Author:  mwhouston [ 11 Aug 2008, 19:12 ]
Post subject:  Cheap chassis cooking up the music

I realise this is not a chip amp but the thread was about cheap chassis.Well I have struck again this time a 6T9 valve amp in a $7 teflon coated baking pan. Not even $40K Halcos have teflon coated chassis. The toroidal OPTs were not suitable in the original build and swapped for some Edcors.

http://www.diyaudioprojects.com/Tubes/6T9-Tube-Amp-Kit/

The amp sounded so good I build another but this time in a more conventional chassis

And don't forget the Tea Box valve preamp. This was bought by a friend the moment he heard it. I used Cardas caps. $100s of caps in a $2 box!!

Image
http://diyaudioprojects.com/Gallery/displayimage.php?pos=-212

Author:  dmc [ 17 Aug 2008, 11:10 ]
Post subject:  Re: My LM3875 based chipamp!

bsgd wrote:
Well this is my LM3875 based chip amp!

It's basically a copy of Mark's LM3875 gainclone chip amp.
I used 6800uF caps instead of the 10000uFs and also used an ALPS black beauty as volume pot.
The tranny I got from an old YAMAHA active subwoofer.

This is a great project for anyone willing to get into audio DIY. It's pretty straight forward to build and there's no high voltage to get you into trouble ;) .


i'm interest this amp too, but i dont know how many ampere EMI filter it is.
it is 2A? :headphones:

Author:  Gio [ 17 Aug 2008, 12:10 ]
Post subject:  Re: My LM3875 based chipamp!

Hi dmc,

Size up the EMI filter using Ohm's Law (Power = Voltage multiplied by Current).

So for the case of 120V mains and a 200VA transformer, use 2A. If you have a 250VA transformer, you will want to use a minimum of 2.5A

Cheers,
Gio

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