Whats the differen Between cary CAD 120s vs120sMK2

As far as I know, the only difference is that Cary adjusted the gain in the mk II version so that preamps with lower gain levels would work with the amp. If you have a preamp with high enough gain, 15 dB or more, you are probably better off with the original 120s, as the 120s mk II may have too much gain for you, and limit the amount of control you have with the volume knob.

I would give Cary technical service a call and ask them for more details.

I have the 120's. The MKII is not necessary with the SLP98P because the preamp has enough gain in it. The only mod I've had done to the amp was getting hi-performance hexfreds and Cardas caps installed. Oh, the faceplate is painted differently on the MKII. If you have the SLP98P, the 120's is a fantastic amp to go with it. I traded a V12R for it. Great amp, but it ran hot enough to cook hamburgers on. Best of luck.