There is no sound module version of the D-70.
The closest relatives are the U-20, U-220 and the MV-30.
The U-20, U-220 and MV-30 also used RS-PCM technology and were compatible with the SN series PCM ROM card library (although not the accompanying parameter data cards).
The MV-30 even had the TVFs (Time Variant Filters) that are found in the D-70, but did not have patches or performances so it could not do splits or layers.
The U-20 and U-220 did have patches so they could do splits and layers but they lacked the TVFs so were not as versatile for synthesis or sound design.
The closest relatives are the U-20, U-220 and the MV-30.
The U-20, U-220 and MV-30 also used RS-PCM technology and were compatible with the SN series PCM ROM card library (although not the accompanying parameter data cards).
The MV-30 even had the TVFs (Time Variant Filters) that are found in the D-70, but did not have patches or performances so it could not do splits or layers.
The U-20 and U-220 did have patches so they could do splits and layers but they lacked the TVFs so were not as versatile for synthesis or sound design.