300b amps do not double their output into 4 ohms (although the beefier Art Audio amps might put out more power into 4 ohms than a classically designed 300b). 8 ohm or higher impedence is preferable, power might even increase a little bit. Higher sensitivity is desirable if you like to listen to your music loud. My speakers are 97db and the 8 watts of 300b is not enough for my listening tastes.
While it is "possible" to drive the Magnepans with the 300b, you will not maximize either of them. Both were designed to work better with other equipment. Listen before you buy.
While it is "possible" to drive the Magnepans with the 300b, you will not maximize either of them. Both were designed to work better with other equipment. Listen before you buy.