lm3886 didn t work :(

[Ahmad_tbp]

hi ..
i just build a lm3886 base , guitar amp from : http://www.generalguitargadgets.com/index.php?option=content&task=view&id=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]

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]

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]

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]

another

 

[Ahmad_tbp]

sorry the pics has no quality ..

 

[Ahmad_tbp]

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