Deviations from universality in the transition from quasiperiodicity to chaos

We present experimental evidence for deviations from universality in the transition to chaos from quasiperiodicity in a nonlinear dynamical system. The dimension of the quasiperiodic set at the transition is 0.795±{}0.005, not 0.87 as predicted by the standard model based on the circle map. We also deviate from predictions of the model at the golden mean: The power spectrum, tongue convergence rate, and spectrum of critical exponents, f({α}), all differ from the theory.