Here is the answer of Kennerton about Vali and HA-1A mk2 :
Dear Sir,
Cayin HA-1A mk2 is a great amplifier. And it works excellent pairing with Vali.
In my opinion, they have better synergy than with a more expensive Auris HA2 SE, for example.
But the sound of this setup may seem a bit warm and smooth. If you like this sound - I highly recommend you Cayin for Vali.
If you prefer a neutral sound with an emphasis on high and medium frequencies, that will suit you more Violectric. They are great for Vali both, but they are absolutely different.
But in my humble opinion, Cayin and Vali are a great Duo. Maybe together they will not miss the analytical, but they are able to give the amazing pleasure of music!