the korg pa300 and the Yamaha keyboards until you get to the PSRS-750 do not have stereo line outputs. They all have a headphone jack out only. When you use the phone output you loose the internal speakers. When the Yamaha 670 comes out you will have stereo line outputs so you can use both. The PSRE443 is the least expensive Yamaha with USB thumb drive capability but still no separate stereo outputs. Casio makes the WK series in the $400.00 price range which do have stereo outputs and sd card storage but the arranger functions don't sound nearly as good as the Yamaha and Korg products.