LM1875 distortion

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I have tried this model of LM1875 audio amplifier.. http://www.electronics-lab.com/blog...25w-hi-fi-audio-amplifier-using-ic-lm1875.jpg .. it makes a huge amount of distortion.... when the input volume is at a lower stage it is cristal clear...bt whenever i increase the volume the sound gets worser..i have used a 8ohm 3W speaker to get the output....more info: 1000uF cap. of 16V electrolitic,100nF 63V cap. of polyester,0.22uF of polyester(marked as 2A104J),1uF electrolitic of 50V,27uF electrolitic of 16V ...i have used 12V 2.5A transformer split voltage...and the most important part is that both the ic and the speaker get so hot...please help me!!!
 
The circuit values look suspect I'd reduce the 10K feedback resistor R4
to 4K7 as the IC may be oscillating with those suggested values....
You are also on quite a low supply for this chip maybe 18V or more would work better
 
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Right, the positive lead of the capactor goes to the "most positive" part of the circuit. With a dual/split supply, this means the positive lead of the capacitor sometimes goes to circuit ground, because the negative lead goes to the negative side of the rectifier, which is "most negative."

But wait a second, just asking, here.

You say you use a "12V 2.5A transformer split voltage." Of course by this you mean a 24 volt center tapped transformer? Because a "split" 12 volts delivers +/- 6 volts, which of course won't work.
 
im a newbie in this business...and that was a silly mistake..but i just followed the circuit diagram and there they made this mistake in their diagram... im using 12-0-12 transformer of 2.5A.....so after all these what do you think?...i mean what kind of change should i make to get a distortion free sound......
 
Yah...i found dc voltage when the amplifier was making distortion...bt when it wasnt making distortion (in lower volume input) i found no dc......i used 47k instead of 10k,distortion decreased,bt gain too

47k is a bit too high, 150k & 47K will give approx 4x gain. (The 1875 is "stable at gain >=10x ".)

about the noise.... maybe your power caps are not big enough. what size are you using (on the power supply board)?
 
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