Looking for LM358 replacement

[Waldo Pulanco]

thanks!! instead of 10k can i use 4.7k? or 10k is much better than 4.7k?

thanks again!!

 

[audioguru]

Thanks MrAl if there is a problem to LM358 i will try to replace it with MC33172!

The MC33172 is not designed for audio because it is fairly noisy. But with gain at only 1 like a piece of wire it might be OK in the stereo encoder. Its works well up to 28kHz.

I have used TL071 single, TL072 dual and TL074 quad audio opamps in audio circuit for many years. Many stereos were made with them. They have low noise, very low distortion and work well up to 100kHz.

ANY opamp works from a single-polarity supply if the (+) input is biased at half the supply voltage.

 

[Waldo Pulanco]

this is simulated using LM324!

the Oscilloscope - XSC2 - is the output of 1khz Audio modulated to 38khz carrier!

the Oscilloscope - XSC1 - is the final output of composite stereo with 19khz pilot!

Spectrum Analyzer - XSA1 - ther is harmonic at the range of 57khz with 2mV only, and the 19khz pilot is 70mV out!!



Uploaded with **broken link removed**

 

[Waldo Pulanco]

The MC33172 is not designed for audio because it is fairly noisy. But with gain at only 1 like a piece of wire it might be OK in the stereo encoder. Its works well up to 28kHz.

I have used TL071 single, TL072 dual and TL074 quad audio opamps in audio circuit for many years. Many stereos were made with them. They have low noise, very low distortion and work well up to 100kHz.

ANY opamp works from a single-polarity supply if the (+) input is biased at half the supply voltage.

i tried TL072 but there is a problem in output! the output is very high peak, i did not change the bias and input resistor and output resistor from LM358!! what the correct value i use when TL072?

 

[Waldo Pulanco]

here is the screenshot that there is no change in value of resistor and capacitor

TL072 = As you can see the 38khz peak is very high at 1V/Div on oscilloscope, there is no Output Audio but i feed it 1Vpeak of 1khz Audio


LM324 = there is A chop of Audio or 1Vpeak at 1khz Audio with modulated 38khz it is also 1V/Div on Scilloscope like on TL072 Oscilloscope!


how to correct the TL072 to make it modulate on Audio like on LM324?

thank you so much!!

 

[MrAl]

Hi,

You need a higher supply voltage to use that op amp. Maybe 10v might do it but 15v better.

 

[audioguru]

The minimum supply for a TL07x opamp is 7V. On some of them the minimum output swing into a 2k ohms load is zero when its supply is 7V but I have used many of them powered from a 9V battery that drops to 6V playing music into a 10k ohms load.

 

[MrAl]

The minimum supply for a TL07x opamp is 7V. On some of them the minimum output swing into a 2k ohms load is zero when its supply is 7V but I have used many of them powered from a 9V battery that drops to 6V playing music into a 10k ohms load.

Hi,

Perhaps some may work at 7v, but due to the data sheet list you can not tell someone it will work at 7v because for a load of 2k the spec is such that the output could be 5 volts away from both rails, so that means with a 12v power supply we know we can get at least 1v peak sine output, but with anything less we may run into clipping or other problems. I suggested 10v to 15v with 10v as min, but now i would like to upgrade that to 12v min for a 1v peak output and that makes sure i covered all the bases. Also biased at 1/2 Vcc.