Using thermoacoustic energy conversions, both amplification and damping of acoustic intensity are demonstrated. A differentially heated regenerator is installed near the velocity node of the resonator and thereby a high specific acoustic impedance and a traveling wave phase are obtained. It is shown that the gain of acoustic intensity resulting from the traveling wave energy conversion reaches 1.7 in a positive temperature gradient and 0.3 in a negative gradient. When the regenerator is replaced with a stack, it is found that the gain reaches 2.3, exceeding the temperature ratio (=1.9) of both ends of the stack. This is brought about by the addition of standing wave energy conversion. The present results would contribute to the development of new acoustic devices using thermoacoustic energy conversion.