This is a busker's dream partner. I purchased it a few years back for exactly that purpose but never did the street musician thing. Watch the video link.

This thing is awesome. Runs on batteries for busking or plug it in. Multiple rhythm styles and patterns. Pattern variations can be triggered hands free with the included foot switch.

Watch my video link provided below.

Here is Korgs description:

A Stereo 80W high-output system provides high-quality sound

The STAGEMAN 80 is a powerful sound system equipped with two 40W high-output amps and two 4-inch stereo speakers. It delivers impressive volume levels that can cover a small or mid-sized performance venue, a listening room, or even a live street performance.

The generous sound takes advantage of the high output, extending from a tight low-frequency range to an extended high-frequency range, and is tuned to give you an extremely well-balanced and natural tone. The sound quality is reminiscent of high-end audio equipment, and will allow every note of your vocals or guitar to shine beautifully.

The amp section uses class-D amps for their good power efficiency. You'll always be able to enjoy clear sound where long battery life is important.

Rhythm machine function with excellent presence

The STAGEMAN 80 is equipped with a large number of high-quality rhythm patterns that take advantage of KORG's advanced sound-generating technology. Based on performances by top-ranking pro drummers and percussionists, these rhythm patterns have a great-feeling groove, and utilize KORG's new "Real Groove Technology" that allows natural and musical-sounding phrases to be generated at any tempo. A total of approximately 3GB of rhythm loops are included, covering a range of 24 genres such as 8-beat, 16-beat, unplugged beats such as Cajon, rock, jazz, and boss nova, with two variations for each genre. Just press a single button to flexibly play back the rhythm you want. The high-quality speakers will produce a realistic and live-sounding rhythm session as though a real drum performance is being staged in front of the listener.

There's a memory function that lets you register your favorite rhythms and playback tempo, as well as a chain function that lets you freely connect individual measures of rhythm styles. You can create original drum tracks to suit the songs that you're performing.