Model of DAC in Uniti Atom

Pretty sure it's the TI Burr Brown PCM 1791A, as is used in another of other Naim digital products.

As Songstream says. 

From Qobuz' review of the Atom :

"The 24-Bit/96 kHz digital-to-analog conversion of the stereo input is made on this card by a Burr-Brown PCM1803 circuit, while a PCM1791 model from the same manufacturer is handling the digital-to-analog conversion of the signals coming from the network or from the other digital inputs, and this up to 24-Bit/384 kHz as well as in DSD."

Thanks all.

On the other hand, the sonic characteristics of a DAC system are far more dependant on the electronic surrounding circuitry surrounding the DAC chip than on the DAC chip itself (so, in practice, the precise chip used doesn't really matter to anyone other than the circuit designer, apart from satisfying curiosity!).