These are Martin Logans, no Apogees. They are a 4 ohm load and are fairly easy to drive. I was temporary driving them with a 45 watt Parasound Zamp while I was waiting for my big amp to arrive.
From the Vantage manual:
What size amplifier should I use?
We recommend an amplifier with 100 to 200 watts
per channel for most applications. Probably less would
be adequate for our smaller hybrids or when used in
home theater where a subwoofer is employed. Our
hybrid designs will perform well with either a tube or
transistorized amplifier, and will reveal the sonic character
of either type. However, it is important that the
amplifier be stable operating into varying impedance
loads: an ideally stable amplifier will typically be able
to deliver nearly twice its rated wattage into 4 Ohms
and should again increase into 2 Ohms.
From the Vantage manual:
What size amplifier should I use?
We recommend an amplifier with 100 to 200 watts
per channel for most applications. Probably less would
be adequate for our smaller hybrids or when used in
home theater where a subwoofer is employed. Our
hybrid designs will perform well with either a tube or
transistorized amplifier, and will reveal the sonic character
of either type. However, it is important that the
amplifier be stable operating into varying impedance
loads: an ideally stable amplifier will typically be able
to deliver nearly twice its rated wattage into 4 Ohms
and should again increase into 2 Ohms.