Chuck
What for do you make beats

lee26loo 我來自強秦隴西 I comes from Qin Dynasty
YES, That is the most simple way. Do not need 2N3055 because the amplifier itself has AF power output stage.

billrussell42
Yes, you can do that, without the power transistors. In fact, you may not need the transformer, if the audio amplifier is powerful enough. If you need 120 volts, an audio amp that can drive that into 16 ohms has a P = E²/R rating, which is 120²/16 = 900 watts. Not undoable, amplifiers for subwoofers frequently are over 1000 watts. And, "almost pure sinewave output" means your oscillator should be a very good one, as many have significant distortion. You can use filters to clean it up if you need to. One point: frequency stability would be poor for a lot of designs, as the components can be temperature sensitive. Ditto with amplitude stability.