What amp settings do you need for U2?
It depends on the song. On a generic five-knob amp, With or Without You starts at Gain 2, Bass 4, Middle 6, Treble 6, Presence 6, Reverb 4; Where the Streets Have No Name starts at Gain 2, Bass 5, Middle 6, Treble 6, Presence 5, Reverb 3. These are starting points, not the settings used on the records.
What gear did U2 use on these songs?
With or Without You: The Edge's 1965 Stratocaster, made into an Infinite Guitar; Vox AC30, probably a Korg SDD-3000 delay (Lanois). Where the Streets Have No Name: Fender Stratocaster (the Edge's own account); Vox AC30 and digital delays (the Edge's rig of the time). Each song page lists the sources behind its rig.
Can you get the U2 tone without the original gear?
Yes. What carries these sounds is the gain structure, the EQ curve, the pickup position and the order of the effects, and all four can be rebuilt on other equipment. Tonelify rewrites each starting point for the amp and guitar you own.