As long as the bit rate is at least 128 kbps or higher, the bass should sound the same as lossless. The main advantages of higher resolution are in timbre of treble and instrumental separation.
An amp does not add more bass unless of course you are using the bass boost function of the amp. It just improves the quality of the bass, making it tighter and better controlled, and sometimes more powerful. It also improves imaging and instrumental separation.