For general audio application customary as a rule use float-point DSP.
From all moderne and available DSP-family draw your attention to C672x cheap (but not bad) DSP-family
Additional advantage for amateur: C672x are available in planal (no BGA) package.
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The 5xxx and 2xxx are fixed point DSPs. Fixed point can also perform floating point operations by software emulation, which is of course slower. But for a guitar
effects a 100MHz TMS320C5402 should be quite ok.