replace lm318 with lm6171

[scrarfussi]

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i want to change that opamp to 6171
but i get 0.14 volts on the output causing the lm3886 to get hot

 

[JohnW]

I suspect that the DC offset you noted is due to oscillation - the LM6171 is a high speed opamp and care needs to be taken to insure stability.

Without seeing your circuit its hard to comment further

 

[scrarfussi]

hi john i posted a picture of my circuit

 

[stratus46]

The LM6171 is a rocket opamp and while you can 'tame' it for audio use, you're not going to achieve that with single sided boards. For that chip I'd use a 4 layer board with an internal ground plane. Amplifiers that fast behave much better at lower impedances. Stuff you can 'get away' with in audio with slower amps won't cut it with 100MHz GBP and 3600 V/uS.

Pick a more appropriate amplifier. There are many to choose from.

G²

 

[scrarfussi]

stratus
what would you suggest for my purpose ?

 

[JohnW]

hi john i posted a picture of my circuit

You posted a PCB layout - I was referring to a schematic - but even looking at the PCB layout and the PCB tracks on the non inverting pin (Pin2) of the Opamp are far to long - with the resultant capacitance that will upset high speed opamps.