I absolutely love my Musical Design D150B amp (s). Actually I had purchased my first one 3 years ago ...but had my recordist buddy who has Quad 989s, the big black ones...he picked them up for me - ( BIG MISTAKE !! ). He kept talking about how transparent his recordings sounded, how sweet, neutral, powerful, stable etc. the amp sounded ON HIS QUADs...that I finally gave in and let him keep them.
It took me about 2 years to come across another D150Bht it up for sale....bought it and it has been the "reference in my system since. Sounds great even without a preamp ( I used a Bel Canto 2.5 dac with remote control for volume control.
Wonder what it ould sound like with a Hillig preamp.