Although the Classic resembles the PV-10 series, my understanding is that it is a completly different circuit design. Which one is better for you depends on what sound characteristics you are looking for.
I owned a PV-10B many years ago, and I had a Classic in house for several weeks (many years later). To me, the Classic is a much better preamp then the PV-10B in almost all respects: build qualty, more neutral, better bass and *much* quieter.
But many guys prefer the sound of the older CJ gear - it's a little warmer and dark than the more recent designs.
I owned a PV-10B many years ago, and I had a Classic in house for several weeks (many years later). To me, the Classic is a much better preamp then the PV-10B in almost all respects: build qualty, more neutral, better bass and *much* quieter.
But many guys prefer the sound of the older CJ gear - it's a little warmer and dark than the more recent designs.