amplifier for low-2 headphones

Stereo headphones are usually connected to the loudspeaker outputs of the power amp via an attenuator. Although this represents the cheapest solution, it does suffer from two significant drawbacks: if the loudspeakers are also switched on whilst the headphones are being used, it is impossible to vary the signal level of the headphones independently of the loudspeakers; secondly, as a result of the output impedance of the attenuator, the damping factor of the system is reduced, which adversely affects the bass reproduction of the headphones.