Sergio, I made good experience with the SRQD11 Controller for ST506 (=MFM) disks made by the Australian Webster Computer Corporation. It can interface one disk (genuine DEC RDs or any other MFMs) to your PDP-11 or MicroVAX without any additional boards or panels. Mine has been running as well in my PDP-11/03 [RT-11] as in my MicroVAX I [VMS], which is VERY picky about disk controllers. Another good choice would be an Emulex QD21 for ESDI disks or even an Emulex UC07 for SCSI disks (if you find one). Ulli