The Kenwood SP-230 external speaker features filtration. There is a switch on the front panel to select input A or B. The rear panel has two audio inputs (RCA phono) and a line output (RCA phone).
The headpone jack on the front panel is post-filtration. 8 ohms maximum input 2 watts.
The SP-230 matches the TS-530S. Physical: 7.2 x 5.3 x 11.5 inches 4 lbs. (180x133x287mm 1.8kg).