The MDx was introduced into production in early 2020; the primary reason for the changeover was to update certain aspects of the digital processor part of the M1 (and all other products) as its use, what features we needed to support had changed and might do so in the future.  The M1 evolved over time, and with the development of MDx,  hardware changes were made to support the network interface better, moving to a newer generation of dual-core DSP processors from Analog Devices and the latest USB receiver from XMOS to allow for higher rates of DSD.

So, in a way, a refreshed updated version of the processor board will improve performance and enable us to manufacture it for the foreseeable future.  When making the hardware changes in this new design, we were also able to make some improvements in how our system works and how we deal with the incoming master clock and clock recovery.  Therefore, fine-tuning of the system was made as part of these changes that required both hardware and software changes,  and the part that would be noted as audible by the listener.