I have a Marantz SR4002 AV receiver. I like it because it is the cheapest AV receiver with HDMI 1.3 and with pre outs and the sound isn't too bad. Anyway, for music, I have the 112. I connect the Marantz to the 112 AV input.
Then I found that both the Marantz and the Naim shares the same remote control code for volume and mute. So when I adjusts the volume on my Marantz, my Naim's volume also changes. Not a very good situation.
Anyone with any good ideas on how to resolve this situation ?

I dont generally deal with 2-channel, but I'm pretty sure there is no alternative code for this product.

Check to see if the Marantz has an alternative remote code option.

With Arcam receivers you can use a different code option in the set up so it doesn't intefere like this. It might be called zone 2 or something?

No alternate codesets available on this product–however, the next model up (SR5002) has RS-232 and an IR flasher input, which, combined with a customizable RF remote (such as Philips Pronto or Universal Remote) + base station, would allow you to route commands ONLY to each device explicitly.

Neither the Marantz, nor the NAC112, offers any RC5 codeset re-mapping.

I have the similar problem with my Marantz going into a 102.
My solution was to place a minidisk in front of the 102 , thus stopping the signal reaching the 102.

When I am using the 102 for stereo duties, I simply remove the minidisc.... small price to pay..