Audiophile Setup with an Iphone 7

Rpeebles, what's your budget?  Also, do you intend to output the Tidal service via your iPhone?  

All good suggestions here. The Ayre Codex with balanced output is also an excellent option. I use the Ayre Codex in my own personal headphone setup as a DAC/AMP. The Chord Mojo or Hugo are also both good options as well. I’m also using a raspberry pi 3 via WIFI to stream Tidal to the Ayre Codex DAC with pretty good results. I use the Lumin app on my iPhone to control Tidal. The Raspberry Pi is surprisingly good for $35 dollars. I used to use the Apple lightening camera adaptor but I stopped because I didn’t like my phone being tied up in the source chain. I rather use the iPhone or ipad as a music streamer controller. I recently purchase the Sparky USBridge (allo.com) for about $180, which as a built in jitter reclock, so the performance should be pretty good. If you have the money to spent...you won't go wrong with the Ayre QX5/20 streamer/DAC.  Good luck!