I have a pair of 350-A monoblocks and a pair of 150 Reference amps sitting right in front of me, I would have to say the most noteable difference is in the sheer raw power, presence, and detailed bass power reserves running either amps in monoblock pairs. Order of sound goes as logic and price would cause you to hope would happen in a perfect world:
one 150-R
one 350-A
two 150's
two 350-s
Running single stereo amps I notice what seems to me to be a very clear sense of effortlessness to material that has high bass demands that would sap an amp of power. This is noticed with efficient 6 ohm full size floorstanding speakers like Meadowlark Blue Heron 2's or Nighthawks. The 150 is very clean and transparent and seems to have plenty of power (it's an actual strong 200wpc) when listened to on it's own for some time. Switch to a 350 and listen to the same demanding material and there is a sense of deeper power reserves that allow everything to remain as it should be even while the amp would be taxed during demanding passages. Step from there to a pair of 150's and you take advantage of the synergies involved with four times the power for a solid 800 into 8 ohms, separate chassis separation, balanced operation, etc. it is very dramatic and worth the difference from a single 350 to the price of two 150's. A pair of the 350's are so dead clean and effortlessly powerful you know beyond any shadow of a doubt that you are listening to distortion levels that are non existant due to the fractional use of the power capability these have at about 1400 watss into 8 ohms, the 350's bench test out at a strong 350 wpc so multiply that by four times for a monoblock. You can clip a speaker hard before ever having any of the pain associated with distortion at high listening levels. The flip side is that the power is so clean that speakers can handle way more power than they could with lower powered typical amps. If you have small efficient speakers a 150 would be an ultimate amp, for larger speakers and high listening levels a 350 is definitely better, monoblocks....I've said it already, they will exceed the performance of any amp made out into the $40k range.
Also I use some of the best power cords made on these amps, $1500 Kaptovators and $3500 Aluminatas, I can make a case for either cord depending on where your monetary sensibilities lie, I use the Aluminatas for my own listening because they make the blackest and deepest background lack of noise threshold I've ever heard. I have done extensive testing against $20k and $30k amplifiers that are being used with several thousand dollar power cords so it's only fair to use the same caliber cord. I will say that these are significantly improved by the cords to the degree that if you spent any substantial time with the good cords you would always miss them having had the chance to get used to them. Joe from JPS gave Dave an Aluminata to try which Dave likes a lot, but he said he had to stop using it because he realized he was doing development work and hearing something different than his customers were going to have with a stock cord.
