To use both a PD-140DS (on a DIGITAL TRIGGER IN port) and an analog snare pad as snare sounds on the TD-50 or TD-50X, connect the analog snare pad to one of the AUX 1-4 jacks and assign a snare instrument to it in the INSTRUMENT settings.
If you connect the analog snare pad to the TRIGGER IN SNARE jack while the PD-140DS is assigned to SNARE, the PD-140DS takes priority and the TRIGGER IN SNARE pad does not produce sound. This is why the AUX 1-4 jack is used instead.
Note: A snare pad connected to an AUX 1-4 jack does not support cross stick or brush techniques.