Hi @Devraj
As you say normally naim pre-amps have the PSU either in the power amp (e.g. NAP200) or external, such as SuperCap. It sound better this way because of the removed electromagnetic fields, vibrations.
Pre-amps were generally released at separate times over the last 50 years. As such they have different PSU requirements. e.g. going from a 202, to a 252, to 552 requires 2 to 3 PSU changes.
We wanted to create a flexible easy to upgrade range with more choice to the customer. We did not want to force a mandatory PSU at this level, we also listened to people wanting less boxes.
The NAC 332 gives the choice of an external PSU to the customer.
The NPX 300 being universal in the NC range allows upgrades to the source or pre-amp or both or swap over from one to the other. It is also possible for everyone to hear the difference an external transformer makes.
To be able to offer this flexibility the pre-amp outputs had to move from the PSU to the back of the pre-amp. It took around 6 months of trying pototypes until the new scheme worked in the listening room. Essentially there’s a new audio star point in the pre-amp formed by adding more regulators.
Best
Steve