Eddie:
The CTK/WK-6XXX models do not provide any type of audio recording or sampling features. Both models have an "Audio In" jack and the WK model also has a "Mic In" jack, but these are strictly for using the keyboard's amplifier and speakers as a PA system. There is no provision for recording signals applied to these jacks. The CTK/WK-7XXX models will record the keyboard's internal sounds and signals applied to the "Mic In" and "Inst In" jacks to the SD Card. Casio calls this recorded data "sampling" data in the sense that it can be converted to a .wav file and exported to a computer, but it can not be edited, looped, cross-faded and assigned to a key or be spread across the keyboard to be "played" by the keys as with an actual sampler, as was partially possible with the older WK-3XXX units. Also, signals applied to the "Audio In" jack can not be recorded by either model, but if you are looking for 5-pin-DIN MIDI IN/OUT jacks, that pretty well excludes most or all of the Casio units for the last 7 or 8 years at least.
George:
If you are looking for very basic sampling features, one of the older WK-3XXX units might interest you, particularly the WK-3800, as it is the newest of that model line. It will sample a sound, and you can assign it to a key or spread it across the keyboard, but this is strictly a "one shot" sample. It can not be looped and cross-faded as a sustaining sound, and total memory for multi-samples is extremely limited.
