This AK10 unit with Toxic Cables - Silver Widow on Ref.1 makes them sound a little lean, even venturing closer towards 1Plus2 tonality. The brightness increases as you lift the volume, if you go really high in volume Ref.1 will thin out, the AK10 lacks any real amounts of output power and the leaning out is probably the outcome of low power.
But I can also tell you I have heard variations between different transports feeding dac/amps. The Galaxy Note 3 I'm using with AK10 makes DacAmp One sound quite vibrant and aggressive (very close to this bright tonality we mention) while running DacAmp from DX80 optical out is slightly smoother and more spacious.
It may simply come down to the transport, although in theory its mean't to change nothing...
My edit above
Lol I will send you a Crystal Cable mini I/C for you to try, to sweeten the sonics for you... or Siltech for crystalline highs and in doing so poison you
Need to just find them now