Outboard DAC

If you route the signal from the SU into an external DAC, you cannot then send it back to the SU amp, so you create a lot of redundancy. You really need a separate streamer and amp to do this rather than an all in one device.

I expect you could if the SU had a digital output but as Chrissu has stated that would mean adding a pre and a power amp unless the Dac had a built in preamp section. Your next choice is wether you need a complete change why not consider adding a nap 200/250 and see what that adds, a smaller upgrade could be a Powerline?

Oh well, thanks for the replies chaps.  I was hoping for a 'simple' upgrade.  Should've known better  

Many people who have tried them consider the Chord DACs to give a worthwhile improvement over the Naim ones, and there are others to consider as well as the 2Qute, but the connectivitupy problem others have mentioned remains, though 

The Hugo, and upwards (TT, Dave) can be used without a preamp, so the digital out from the SU (there is one) can go to the DAC which could feed direct to a power amp, but unless the SU has an input direct to its power amp, which I don't think it does (?), that would mean an additional power amp. The alternative is to feed the DAC into an analogue input of the SU, but then deeding a separate renderer before the DAC. WHat music store do you use?  Some, like the new UNiti Core, have a built-in renderer so could do that, but if a NAS then it would require  something else to achieve it. More info can be provided if you were considering going down such a route.

Thanks for the info IB.  I guessif I go down the upgrade route.....it's going to be expensive.