Hmm, not sure that I would look to a Touch as a significant sound upgrade if I already had a Duet + a good external DAC.
The reason I think this is that with the same external DACs, I did not notice a significant sound change at all moving to Touch from Roku Soundbridge, which I would expect to be a bigger change. The move to the touch was justified from both a performance and reliability and usability perspective in that the Roku SOundbridge was an older device that was no longer actively supported or sold. I never have had an issue with sound quality of either ROku or Touch running through the same DAC and system.
What are your goals in making a change? Knowing what kind of sound you are shooting for would help.
The reason I think this is that with the same external DACs, I did not notice a significant sound change at all moving to Touch from Roku Soundbridge, which I would expect to be a bigger change. The move to the touch was justified from both a performance and reliability and usability perspective in that the Roku SOundbridge was an older device that was no longer actively supported or sold. I never have had an issue with sound quality of either ROku or Touch running through the same DAC and system.
What are your goals in making a change? Knowing what kind of sound you are shooting for would help.