naim set up question

I have the nac 42 with nap 110 and snaps.

I do not understand how the snaps fits into this system. The preamp seems to power up with just the output attached to the input of the amp. There is no 120v power cord for the preamp. I thought the snaps was a separate power supply for the pre-amp. The system works well without the snaps in place.

Any advice will be appreciated

The amp has a power supply that is shared with the preamp if the Snaps or Hicap is not used. The Snaps has an interconnect that plugs into the 42 as does the 110. This is beneficial in that the amp uses its power supply alone and the Snaps is for the preamp and is better than the shared one in the amp. The Snaps is plugged into a wall outlet. If you have the factory interconnects remember that they are directional. It's been a long time but it seems the interconnects have a black band on one end. The black band end goes into the preamp. From the preamp the black band goes into the amp. My 42 was clearly labeled at each socket in the back.

When the interconnect from the snaps is connected to the pre-amp, does the power supply from the amp discontinue in some way?

The amplifier power supply is dedicated for amp use when you have the Snaps hooked up correctly. A Hicap is a very nice upgrade down the road.