Dayton Audio DTA-1 amp ($60)

Dayton B562 speakers ($30 for pair)

This is a "class T" amplifier. There is only knob on it, the volume control. If it is a good amplifier, that should be all you need!

What also makes a very big difference - careful placement of the speakers relative to a listening spot on the couch! The angle of the speakers is surprisingly critical. When it is right, the singer seems to be straight in front of you, somehow I can hear the words much better.