lm3886 didn t work :(

Ahmad_tbp · 27th January 2006, 09:28 PM

hi ..
i just build a lm3886 base , guitar amp from : http://www.generalguitargadgets.com/...185&Itemid=210

but when i test it for the first time it didn t work ,,when i turn it on it s a very loud noise come out of speaker, and the ic become too hot ,( even w heatsink ) i check all the board again and again .,,checked the power supply , everythin seems w no problem ... s there any problem w original schematic and pcb ???

velmeran42 · 28th January 2006, 05:26 AM

The design looks fine to me, more or less the reference design from National Semiconductor. Can you post pictures of your amp? Probed around (cautiously) with a multi-meter?

Good luck
-Velmeran42

lineup · 28th January 2006, 05:36 AM

Add a zobel filter.
This will prevent oscillation.

You put a 10 Ohm resistor in series with a 100nF film cap.

This you solder across the output pins of PCB.

out+terminal
R10 Ohm
C 100nF
out-terminal

Ahmad_tbp · 28th January 2006, 08:26 AM

hi ... i m a very newbie for electronic , i can t test it too much , but i did anythin i could .. but nothin ,, the only thing i can think s the ic was dead already when i bought it ...

Ahmad_tbp · 28th January 2006, 08:27 AM

another

Ahmad_tbp · 28th January 2006, 08:28 AM

sorry the pics has no quality ..

Ahmad_tbp · 28th January 2006, 09:11 AM

i forgot to say i m usin -24/+24 for supply

27th January 2006, 09:28 PM	#1
Ahmad_tbp diyAudio Member Join Date: Jul 2004 Location: Iran/Shiraz	lm3886 didn t work :( hi .. i just build a lm3886 base , guitar amp from : http://www.generalguitargadgets.com/...185&Itemid=210 but when i test it for the first time it didn t work ,,when i turn it on it s a very loud noise come out of speaker, and the ic become too hot ,( even w heatsink ) i check all the board again and again .,,checked the power supply , everythin seems w no problem ... s there any problem w original schematic and pcb ??? __________________ Rest my eyes from the world. This dying place, it's so absurd.

28th January 2006, 05:36 AM	#3
lineup diyAudio Member Join Date: Dec 2005 Location: the north	Add a zobel filter. This will prevent oscillation. You put a 10 Ohm resistor in series with a 100nF film cap. This you solder across the output pins of PCB. out+terminal R10 Ohm C 100nF out-terminal __________________ lineup

28th January 2006, 09:11 AM	#7
Ahmad_tbp diyAudio Member Join Date: Jul 2004 Location: Iran/Shiraz	i forgot to say i m usin -24/+24 for supply __________________ Rest my eyes from the world. This dying place, it's so absurd.

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28th January 2006, 05:26 AM	#2
velmeran42 diyAudio Member Join Date: Jan 2005 Location: Issaquah, WA	The design looks fine to me, more or less the reference design from National Semiconductor. Can you post pictures of your amp? Probed around (cautiously) with a multi-meter? Good luck -Velmeran42

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