freestompboxes.org

I want to build a Tim using Dirtbox layout at https://dirtboxlayouts.blogspot.com/202 ... e-tim.html and see conflicting informations on the JRC 4558 vs 4559:
According to this page https://html.alldatasheet.com/html-pdf/ ... 4558D.html, the only difference would be the slew rate (1 for the 4558 and 2 for the 4559), so that a 4558 would be a poor substitute for a 4559 in this application, right? If so, what would be a proper alternative?

These two are fine substitutes for each other in a guitar pedal, you won't hear a difference.

Thanks @mauman

My initial thinking was that the slew rate was a major factor since we are trying to overdrive the diodes and that the 4558 would generate only half the voltage of the 4559. However, thinking in log scale, halving the slew rate will only cut 3db to the output voltage which will still be sufficient to overdrive the diodes.
Am I right?

But the Tim is only demanding around 40 dB from the op amp, you've got plenty to go until you run out of bandwidth.

FiveseveN wrote: ↑07 May 2023, 18:58 But the Tim is only demanding around 40 dB from the op amp, you've got plenty to go until you run out of bandwidth.

That makes a lot of sense now. Thanks a lot.

The actual difference between the two parameters may not be so great, JRC4558, JRC4559 and JRC4562 architecture is the same, it is likely to be the same assembly line production, by screening the monomer parameter error to distinguish the model.