Mcintosh mx136 vs Mcintosh Mx150

Did someone had experience with both of those preamps?
Which one has better sound?
I've found that my MX 136 has an excellent phono section which produces a deep and wide sound stage. Low level detail ( room ambience) is clearly reproduced and the soundstage is both wide and deep. I do use the pure stereo mode and find that this preamp is sonically very neutral and very quiet. I do not route video through my MX 136 as the HDMI circuits are Version1 and do not handle audio. 
Right now im running an older MX-120 in 2 channel paired with Mcintosh XRT-28 speakers and the sound is not lacking in any area,the MX compares very well against my C-2200 and C-2500 which are both tube models and an MX-19 that was such a low price i just had to buy it , im new to Mcintosh pre pros for theater but have ran them for years as 2 channel units & found them to sound great all the way back to the C-39 .