I create a mono amplifier and it plays well but the IC and resistor heats up. I only use 3 speaker 2ohms connected in series




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hi Omgits3,
Welcome to AAC.
Do you have an oscilloscope that you could use to check the Output, it may be oscillating.
Your drawing is difficult to read, bigger would be better, also add the component values.
E

 

I suspect R10 heats up due to a DC offset on the output. I suspect the opamp heats up due to it trying to drive too high a value of load but as Eric points out you have not given component values so we can't calculate it this is so. This could also be the cause of the DC offset on the output.

Les.

 

Hello ericgibbs,
I dont have oscilloscope i only use analog multimeter. Here is the site where i get the amplifier. https://www.eeweb.com/extreme-circuits/10w-audio-amplifier-with-bass-boost

 

Do these tests with no input to the amplifier.
Set your meter to about the 20 volt AC and connect it via a non polorised capacitor (Any value you have above 0.47 uf) between ground and the junction of R9 and R10 and note the reading. (It should be zero. If it is not then the amplifier is oscillating.)

Set your meter back to about the 20 volt DC range.

Disconnect the speakers. Measure all these voltages with respect to ground and post the results. As your meter is analogue it does not read negative voltages so you will have to do these tests twice reversing the test probes.
Make sure you include the polarity of the readings in the results
1 The voltage at the junction of R9 and R10
Measure these voltages directly on the pins of half of the NE5532 that you have used.
2 Pin 1 / 7
3 Pin 2 / 6
4 Pin 3 /5
5 Pin 1 / 7
6 Pin 4
7 Pin 8

Other points. I suggest that you do not leave the inputs on the unused half of the NE5532 floating. Connect the unused + input to ground via a 100K resistor. Connect unused - input to the unused output via a 100K resistor.
You have the wrong value resistor for R10. It should be 0.22 ohms NOT 22 ohms. This is not the cause of the fault. It will just greatly reduce the output when you get the amplifier working.

Les.

 

Hi LesJones,
Im sorry but i dont know what exactly to do. i don't know where to put my test probe and where to measure. If u dont mind sir can u please make step by step procedures? I hope it is ok for u sir.
Thank u very much for help

 

Hi LesJones,
Im sorry but i dont know what exactly to do. i don't know where to put my test probe and where to measure. If u dont mind sir can u please make step by step procedures? I hope it is ok for u sir.
Thank u very much for help

Put your Negative lead on the Ground Terminal which is the junction of C10,C11

Put your Positive lead on the speaker output at R9,R10 Junction.