The SVP won't break up as it's not designed to. The SVP PRO will add valve drive by pushing a 12AU7 into overdrive, but it's not just diode clipping.
10001c1_.pdf
Page 2 shows the arrangement and use of the 5 preamp tubes - V4 is the 12AU7 responsible for the 'drive' circuit. It can sound a bit 'fizzy' when running direct to a desk, but through a power amp and an 8x10 it's glorious.