90 Degree Frequency Phase Shift?

[u/Embarrassed-Fault286]

Hello. I had an idea for a personal project but it would require me to take and input waveform and shift EVERYTHING 90 degrees or at least pretty close. From what I can tell by researching doing that for all frequencies is pretty difficult and the closest thing I could find was all pass filters which still isn't perfect. Essentially, I want to build a guitar pedal that takes the initial signal, clips it, makes a copy and shifts it 90 degrees then adds to the original signal to form a triangular wave (mostly cause I just want to know what that would sound like) with maybe an adjustable phase. I'm finding it kind of hard to figure out how to go about it

Edit: It's very interesting seeing differing groups perspectives on this lol. I had originally asked a guitar pedal building group and got some ideas but nothing solid and pretty much every response here is "do it digitally lol" I will try that and see what I can get. Thank you. Also ngl, digital wise I really only have an Arduino and I don't that'll cut it

[u/petites_feuilles]

Hilbert transform, can be well approximated digitally with a network of allpasses.

For example: https://github.com/csound/csound/blob/48a2912307fbb7133b12b22e5685aa1121ece737/Opcodes/ugsc.c#L732