MHDT Orchid or Lampizator Amber 3?

It should be noted that some if not all DACs accel at a specific connection/input

Comparing just spdif for example across the board is pretty limiting or at least can be as many designs put everything into say implementation of their USB and that particular DAC will perform best at.
But if spdif is the connection type one wants then you need to consider that variable significantly. Again regardless of connection type, or one’s preferences, it’s all about the DACs implementation of said connection type.

Well if the socket enables one to roll tubes that sound better than the WE, then wonderful.  I would check with MHDT as these other tubes will have varying voltage requirements. 

Brownsfan, point well taken. It sounds like you have a very well sorted system. Trying one of these DACs in your system may be a good next step. 

I believe Amber 3 can play native DSD 64 and 128 files unlike Orchid. Has anyone tested different file types (high res flac & DS) and their impression?

Jiun of MHDT Labs said no damage to the Orchid to use adapter and try 6DJ8 tube. He said "deserve to have a trial".