The internal phono-stage of the TTV2 is designed for use with the Alva MC cartridge, and is based upon the Alva Duo.
If you decide to use an external phono-stage with the Alva TTV2 and stock Alva MC cartridge, then it is important to note a few key specifications that will help you when deciding on a model.
The phono-stage should be able to support a load impedance of 47kΩ as recommended for the Alva MC.
The stock internal phono-stage has an input capacitance of 100pF, and we would recommend choosing a unit that matches this, or has the ability to switch between a variety of capacitance values.
If you decide to use a third-party cartridge with the Alva TTV2, as well as an external phono-stage then it would be important to consult the cartridge specifications to inform your choice of phono-stage.