Trying both units and choosing the best based upon performance is the best course of action. However if that is not possible looking at the device specifications may offer some insight.
N20 relevant features: linear power supply ; Double Isolated Gigabit Ethernet LAN; OCXO clock; Word clock input facilitates.
N200 relevant features: linear power supply, Double Isolated Gigabit Ethernet LAN; TCXO Clock
There should be an audible difference in the AES and SPIDF digital output between the Aurender devices because of the clock differences. The N20 should have an improved sound.
When using a USB Audio 2.0 Standard asynchronous connection from either Aurender device the DAC runs off a clock that’s completely independent of the USB clock. Synchronization between data rates is maintained by use of a separate feedback path via the USB interface.
The updated N20 clock should not have a material effect on the quality of the USB sound output when compared to the N200.
Theoretically when using USB audio output both devices should have similar sound based upon the same USB circuit, linear power supplies, double isolated Gigabit Ethernet LAN and operating system. The difference between the two devices should come down to internal noise suppression.
If using the AES or SPIDF output from the Aurender then IMHO the extra cost of the N20 would be worth while. However if your only using USB output then IMHO the N200 might be a more cost effective option.
