The Studio Preamp has an unusually sweet clean channel. Especially so without the GEQ. The lead channel unfortunately, or fortunately depending on the player, is more liquid gain sounding like a Mark III. It is distinctly different from say a Mark I or I IA. But again, the clean channel is excellent, and can dial in some convincing Garcia or Weir tone... and they are virtually indestructible.
I haven't paired it with a Mac but have run it with an old EV 7300 stereo power amp with great results...
"It all rolls into one..."