There is a common assumption that any reactive load is more difficult for an amplifier to drive than a purely resistive one; however, it is devoutly to be wished that people would say what they mean by 'difficult'. It could mean that stability margins are reduced, or that the stresses on the output devices are increased. Both problems can exist, but I suspect that this belief is rooted in anthropomorphic thinking. It is easy to assume that if a signal is more complex to contemplate, it is harder for an amplifier to handle. This is not, however, true; it is not necessary to understand the laws of physics to obey them. Everything does anyway.

When solid-state amplifiers show instability it is always at ultrasonic frequencies, assuming we are not grappling with some historical curiosity that has AC coupling in the forward signal path. It never occurs in the middle of the audio band although many loudspeakers have major convulsions in their impedance curves in this region. Reactive loading can and does imperil stability at high frequencies unless precautions are taken, usually in the form of an output inductor. It does not cause oscillation or ringing mid-band.

Reactive loads do increase output device stresses. In particular peak power dissipation is increased by the altered voltage/current phase relationships in a reactive load.