Voyetra MPU interfaces (which use genuine Roland chipsets)
in chronological order:

ALL  ... hardwired to address 330-337 (cannot be changed)


OP-4001 ... IRQ 2 (9) hardwired
V-4001 ...  IRQ 2 (9) hardwired (for first half of production run)


V-4001 ...  IRQ choices, by jumpers, are 3,4,7,& 2 (default)  
            (for second half of production run)  
V-4000 ...  IRQ choices, by jumpers, are 3,4,7,& 2 (default)  


The IRQ jumpers would be just above the (8 bit ISA) "goldfinger" contacts.  
The same scheme was used on the V-22/24s series cards.