PMB,
Your consideration of the Cary 300b amp is well founded, given the optimal load and sensitivity of the Zu speaker. A 300b tube amp can be slow, very fast or any where along this spectrum. Much depeneds on the power supply/ transformer quaility( which should be good with the Cary). Another important variable is the choice of which 300b and driver tube you choose(they make substantial differences in sonic presentation). 6 moons has done very detailed comparisions and found fundamental character changes based simply on which tube was osed. They also found that the driver tube impacts the sound as much/more than the 300b output choice. I can tell you from personal experience that a properly implemented 300b amp can be quite fast and dynamic, yet still provide uncanny realism and presence. Read the 6 moons review of the TJ Full Music SE 300b/6sn7 driver for an example.
Your consideration of the Cary 300b amp is well founded, given the optimal load and sensitivity of the Zu speaker. A 300b tube amp can be slow, very fast or any where along this spectrum. Much depeneds on the power supply/ transformer quaility( which should be good with the Cary). Another important variable is the choice of which 300b and driver tube you choose(they make substantial differences in sonic presentation). 6 moons has done very detailed comparisions and found fundamental character changes based simply on which tube was osed. They also found that the driver tube impacts the sound as much/more than the 300b output choice. I can tell you from personal experience that a properly implemented 300b amp can be quite fast and dynamic, yet still provide uncanny realism and presence. Read the 6 moons review of the TJ Full Music SE 300b/6sn7 driver for an example.