Can anyone recommend a small 10-30watt DIY amp?

rurockn · 10th October 2006, 06:36 AM

I live in the machine controls world at work but I would like to try and expand my electronics horizon and work on a project for myself - any advice would be greatly appreciated. And please don't laugh! Its hopefully a starting ground for a future hobby that will keep me from thinking electronics are boring and that I need a new job, haha.

I would like to build a small self contained amplified speaker box that I can plug my MP3 player into when I am at my desk. I will be using a speaker that was donated to me:

Blaupunkt car audio 2-way
Model: PCxb402
2-35 watts RMS
frequency response: 80-20,000 Hz
sensitivity: 90 dB

If anybody has plans or can veer me in the right direction it would be greatly appreciated. Thanks for reading.

juma · 11th October 2006, 09:11 AM

Hi rurockn,
your speaker will surely enjoy the company of LM1875 (nice sounding, cheap, very easy to construct). Yes, it can be made to sound better than datasheet schematic, but with those car speakers and MP3 player you'll never notice the difference.

Look for the schematic and datasheet at:
http://www.national.com/pf/LM/LM1875.html

Crazy-Stereo · 11th October 2006, 11:23 AM

Here is another schematic that i found, using LM1875 too.

http://www.sound.westhost.com/project72.htm

phn · 11th October 2006, 08:27 PM

Simplified/Gaincard schematic: http://www.geocities.com/rjm003.geo/...io/diy_gc.html

Hardwired Gainclone: http://dogbreath.de/Chipamps/GainCar...nCardCopy.html

rurockn · 11th October 2006, 10:09 PM

Thank you for the advice, I will have a look at those links right now.

Nordic · 11th October 2006, 11:02 PM

Why not try your hand at building a proper gainlcone channel, try Decibel dungeon's basic inverted GC. Just remember that the input cap is incorrectly shown as 47uF, but it should read 4uf7. (I've pointed it out to Nuuk, but he's a busy man).

I think the LM3875 GC is realy in a sweetspot between 20 and 30 watts. And I don't think you can realistcaly compare the sound quality to the baby chip...

Do you know it it is an 8- or 4 ohm speaker...?

Leolabs · 13th October 2006, 02:39 PM

Go for LM3875.

10th October 2006, 06:36 AM	#1
rurockn diyAudio Member Join Date: Apr 2005 Location: chicago	Can anyone recommend a small 10-30watt DIY amp? I live in the machine controls world at work but I would like to try and expand my electronics horizon and work on a project for myself - any advice would be greatly appreciated. And please don't laugh! Its hopefully a starting ground for a future hobby that will keep me from thinking electronics are boring and that I need a new job, haha. I would like to build a small self contained amplified speaker box that I can plug my MP3 player into when I am at my desk. I will be using a speaker that was donated to me: Blaupunkt car audio 2-way Model: PCxb402 2-35 watts RMS frequency response: 80-20,000 Hz sensitivity: 90 dB If anybody has plans or can veer me in the right direction it would be greatly appreciated. Thanks for reading.

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11th October 2006, 09:11 AM	#2
juma diyAudio Member Join Date: Nov 2005 Location: Zemun	Hi rurockn, your speaker will surely enjoy the company of LM1875 (nice sounding, cheap, very easy to construct). Yes, it can be made to sound better than datasheet schematic, but with those car speakers and MP3 player you'll never notice the difference. Look for the schematic and datasheet at: http://www.national.com/pf/LM/LM1875.html

11th October 2006, 11:23 AM	#3
Crazy-Stereo diyAudio Member Join Date: Sep 2005 Location: Sarawak (aka Borneo)	Here is another schematic that i found, using LM1875 too. http://www.sound.westhost.com/project72.htm

11th October 2006, 08:27 PM	#4
phn diyAudio Member Join Date: Oct 2004	Simplified/Gaincard schematic: http://www.geocities.com/rjm003.geo/...io/diy_gc.html Hardwired Gainclone: http://dogbreath.de/Chipamps/GainCar...nCardCopy.html

11th October 2006, 10:09 PM	#5
rurockn diyAudio Member Join Date: Apr 2005 Location: chicago	Thank you for the advice, I will have a look at those links right now.

11th October 2006, 11:02 PM	#6
Nordic diyAudio Member Join Date: Sep 2005	Why not try your hand at building a proper gainlcone channel, try Decibel dungeon's basic inverted GC. Just remember that the input cap is incorrectly shown as 47uF, but it should read 4uf7. (I've pointed it out to Nuuk, but he's a busy man). I think the LM3875 GC is realy in a sweetspot between 20 and 30 watts. And I don't think you can realistcaly compare the sound quality to the baby chip... Do you know it it is an 8- or 4 ohm speaker...?

13th October 2006, 02:39 PM	#7
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Go for LM3875.