Audioman ;
Assuming your reason for asking about Class A is to get clear,clean sound with great low level resolution and good soundstaging , I suggest you look into the Class D Audio SDS power amps . Most Class A run hot , either solid state or tubes, and these do not. They are also a small form factor and very affordable , IMO . I tried one after my 2A3 SET amps and found the sound nearly identical , except better in all regards and also with NO hum or noticeable distortion . None are as low-powered as you mentioned , but they are very energy efficient and you can use as much or little of the available power as needed by turning the volume control of your control amp . This is their lowest powered amp in their best series ;
http://www.classdaudio.com/sds-series-amplifiers/sds-120c-class-d-audio-power-amplifier/ Read their " Testimomials "
Assuming your reason for asking about Class A is to get clear,clean sound with great low level resolution and good soundstaging , I suggest you look into the Class D Audio SDS power amps . Most Class A run hot , either solid state or tubes, and these do not. They are also a small form factor and very affordable , IMO . I tried one after my 2A3 SET amps and found the sound nearly identical , except better in all regards and also with NO hum or noticeable distortion . None are as low-powered as you mentioned , but they are very energy efficient and you can use as much or little of the available power as needed by turning the volume control of your control amp . This is their lowest powered amp in their best series ;
http://www.classdaudio.com/sds-series-amplifiers/sds-120c-class-d-audio-power-amplifier/ Read their " Testimomials "