The magic of the classic 741

[Lonkero]

Have you guys noticed how with certaing biasing the 741 acts like there is very tiny hearable "delay" between the signal and your actual playing? I mean eg. in DOD 250 grey where the biasing is 22k+22k+470k, you can clearly hear how the 741 reacts kind of lazy to your playing, especially when you shred really fast. It feels like sound from your amp with the dod 250 drags behind your fingers...but it's sometimes really hard to notice. But I like the way 741 reacts with this biasing.

Does this have something to do with the slow slew rate it has? How does this slew rate actually affects to the sound? Could it be that with 741 the slow slew rate really causes the thing which ear interprets as tiny delay? Or is it maybe more how it reacts with the notes?


Ps. Don't mind about the topic, it put it purposively to get some attention

[DrNomis]

Have you guys noticed how with certaing biasing the 741 acts like there is very tiny hearable "delay" between the signal and your actual playing? I mean eg. in DOD 250 grey where the biasing is 22k+22k+470k, you can clearly hear how the 741 reacts kind of lazy to your playing, especially when you shred really fast. It feels like sound from your amp with the dod 250 drags behind your fingers...but it's sometimes really hard to notice. But I like the way 741 reacts with this biasing.

Does this have something to do with the slow slew rate it has? How does this slew rate actually affects to the sound? Could it be that with 741 the slow slew rate really causes the thing which ear interprets as tiny delay? Or is it maybe more how it reacts with the notes?


Ps. Don't mind about the topic, it put it purposively to get some attention

Those are actually very good questions, and I would have to agree, slew rate is a measure of how quickly the output can swing from one extreme to the other, it's usually quoted as voltage/time, so an op amp that has a slew-rate of say 30V/uS (microsecond) is capable of an output swing of 30V over a time period of 1 microsecond, if we compare that to another op amp with a slew-rate of say 1V/ 1 Second, then that op-amp's slew rate is slower, if we were to feed a sine wave into the op-amp with the slower slew-rate, we would find that everything was okay up untill a certain point as we increased the frequency of the signal, past that certain point, instead of a sine wave, we would get something like a triangle wave because the signal is changing too fast for the op-amp to be able to keep up with it, this is actually a form of distortion which is called Slew-Rate Distortion, and increases as the input frequency goes up....

Some effects circuits actually exploit this Slew-Rate Distortion, hence the reason you tend to see the LM741 IC being used when when commonsense would dictate otherwise, because the Slew-Rate Distortion has a softening effect, I wouldn't be surprised if Slew-Rate Distortion has some contribution to the "Valve Sound" in combination with other factors....

[ppluis0]

Also the ProCo Rat employs an LM308, that has a low slew rate type.

Perhaps the sound of that unis has to do with that op amp.

Cheers,
Jose