Looking for LM358 replacement

[Waldo Pulanco]

I am looking for LM358 Replacement, that there is no change the value of resistor or other component for the use of LM358. but low distortion and high frequency which is about 100khz and sigle supply almost similar to LM358 dual opamp.

according to an expert the LM358 is
The lousy old LM358 has problems above only 2kHz so it should never be used for audio.
The lousy old LM358 has crossover distortion so it should never be used for audio.

thanks in advance!!

 

[MrAl]

Hi,

Now i wonder who told you that (big chuckle as if i dont already know and so does everyone else here hee hee).

That is partially correct, but on the other hand it does depend on what you want to use it for and the frequency specification alone is not enough to go on. We also have to have some idea what kind of output amplitude you are after and if you have any specific distortion goals in mind. If you only need low output amplitude it may work for you, but if your needs are too great then another op amp will have to be found.

So you have to more or less specify the following:
1. Frequency (max).
2. Output amplitude peak max.
3. Supply voltages available.
4. If possible, the actual application it is to be used in.

If you can work with a +5v supply there are a number of possibilities for faster op amps.

The TL4581 op amp is an interesting device. It may or may not fit your application though and there are so many op amps out there to choose from, so it's best to state as many spec's as you can here.

 

[Waldo Pulanco]

Sorry hehehehe!! I use it with stereo coder!! the max frequency is 15khz the supply voltage is about 8v the output voltage peak is a max of 1v peak the input voltage is max of 1v peak..

thanks!!S

 

[MrAl]

Hello again,

What supply voltages will you be using? Will the output swing plus and minus?

The LM358 can handle 15kHz at 1v peak output (2v peak to peak) because the fastest dv/dt of a 15kHz sine is only about 0.1 v/us (0.1 volts per microsecond) and the LM358 can do 0.5 v/us.

To get the distortion in line, you have to bias the output with a resistor from the most negative supply voltage to the output. That eliminates the crossover distortion.

If this is to be a very high end system you may want to use a low distortion type op amp made exclusively for audio applications though. If you can test the LM358 as above then you can decide for yourself.

 

[Waldo Pulanco]

what swing plus and minus?

can i use the LM358 with positive right and negative left? or for short R-L

 

[MrAl]

Not sure what you mean by "Right" or "Left"

 

[audioguru]

Hee, hee. You forgot that the lousy old LM358 has too much hiss to be used for audio!

ANY opamp can use a single supply voltage if it is biased at half the supply voltage.

L-R is not said to be "positive left and negative right". It is the difference between left and right (left and right are out-of-phase) and is said to be left minus right. If left is the same as right (L+R which is mono) then there is no L-R.

In an FM stereo coder the L-R 38kHz sidebands are from 23kHz to 53kHz which is much too high for a lousy old LM358.

 

[audioguru]

It gets very confusing when your stereo coder thread is on a different website forum.

The LM358 lousy old dual opamp in Harry's stereo coder is not used for L-R. It is used as left channel and right channel input audio (20Hz to 15kHz) buffers with a gain of 1.
Switching the left and right channels on and off (alternating) at 38kHz creates the L-R 38kHz sidebands.

 

[MrAl]

Hi,

It would help much to see the circuit here. The LM358 can be made to be quiet if the output is biased correctly. I dont know if i can recommend it for high end audio systems, but for some things it will work just fine. I've used it in audio and it does appear in some commercial audio equipment.

 

[Waldo Pulanco]

It gets very confusing when your stereo coder thread is on a different website forum.

The LM358 lousy old dual opamp in Harry's stereo coder is not used for L-R. It is used as left channel and right channel input audio (20Hz to 15kHz) buffers with a gain of 1.
Switching the left and right channels on and off (alternating) at 38kHz creates the L-R 38kHz sidebands.

hehehe!! i forgot to post it on the forum!! i have 3 forum that similar post to ask an expert for every forum so i combine it!!

 

[audioguru]

The LM358 can be made to be quiet if the output is biased correctly.

Biasing the output in class-A eliminates the crossover distortion but has no effect on the high hiss level.

 

[MrAl]

hehehe!! i forgot to post it on the forum!! i have 3 forum that similar post to ask an expert for every forum so i combine it!!

Hi,

Post the circuit so we can all take a look ok?

 

[MrAl]

Biasing the output in class-A eliminates the crossover distortion but has no effect on the high hiss level.

Hi ag,

That's interesting because when i used one for a stereo headphone amplifier i never noticed any 'hiss'. It as quiet as a desert during those quiet passages. I might still have the schematic around in an old notebook too. Maybe i'll try to look it up so we can see why it was so good then.
All i remember is the gain didnt have to be super high, but not too much else because this was more than 30 years ago. I do remember it was quiet though that's why your 'hiss' reply caught my attention.

In any case, i'd like to see the circuit he is talking about so i can take a look too if someone could provide a link or something..thanks.

 

[Waldo Pulanco]

i was change the opamp to LM324

theere is a problem uploading attachment i will upload it to other hosting!!

 

[Waldo Pulanco]

here is


Uploaded with ImageShack.us

 

[audioguru]

Maybe the hiss level from an LM358 is OK when it has a gain of only 1. Gain amplifies the hiss, especially when it is a mic preamp.
The website called Headwise has headphones amplifier circuits. They bias the outputs of an OPA2134 dual opamp in class-A so that its 0.00008% crossover distortion is less.
The hiss from an OPA2134 is 7 times less than the LM358 (ST Micro is the only manufacturer of the LM358 that spec's its noise level).

Guess what? A lousy old LM324 is exactly the same as a lousy old LM358 except it has 4 opamps instead of 2 opamps.
They have hiss because in those days a long time ago they could not reduce the hiss. They have crossover distortion and a slow slew rate because they are "low power".
You must properly disable the unused opamps. Why don't you use a good audio dual opamp instead?

 

[Waldo Pulanco]

I have 4pcs of LM324 and 1pcs of LM358! what kind of dual opamp can i use? i have a problem on biasing specially on Opamp im not expert! if you give me a dual opamp what value of resistor and capacitor that i put it?

thank you so much for the answer of my post you are great!!

 

[MrAl]

Hello again,

AudioGuru:
Yes, low gain is the key i guess. That's why i always like to ask about how it will be used because that makes or breaks the device's usefulness in the application.
But i cant help but agree that i think a better op amp is in order here too, one made for low distortion, although i dont know what his target consumer is going to expect. Is this for transmitting voice, guitar, general music, etc.
I seem to remember a long time ago they made a very low cost dual op amp made just for audio apps, but cant remember the part number.

Waldo:
Oh ok, so this is a stereo ENCODER. The 'coder' terminology threw me a little there.
Now that we know exactly what this is going to be used for, it appears that you might be better off with a better op amp made for audio. There's a chance it might work ok though because i see you are using it in a low gain mode too, and that reduces the noise, but it depends on what you or whomever you are building this for likes or doesnt like, as in if they hear any objectionable noise. Depending on the output swing you may have to add resistors to ground on the output however, but i havent looked into this for this circuit too much yet.
So you may get away with using this op amp here. You can certainly test with it just to get everything working properly.

 

[Waldo Pulanco]

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

 

[MrAl]

Hi again,

You're welcome.

Also, i took a closer look at the circuit and if you want to try the LM358 or LM324 first then you'll need to connect 10k resistors from the output of each op amp to ground. That keeps the upper drive transistor of each op amp 'on' all the time so that the lower transistor can not turn on. The lower transistor inside the op amp is what causes the crossover distortion and it is significant without the 10k resistor.

Did you check to see if that op amp was good for audio purposes? It looks like it may have a similar output stage which means it may have crossover distortion as well.
In the data sheet they are claiming an "all NPN output stage" yet in the internal diagram they picture a PNP pulldown just like the LM358. So it's anybody's guess. If it is an all NPN output stage then it is probably biased to keep both transistors slightly 'on' at all times, which means little crossover distortion. There is also the possibility that this part is being discontinued also.