Lamzator Amber 2 DAC

I've been trying to get some input for the tube options for my Amber DAC over at their forum from the owners but with no luck. There are a couple of open threads on the subject. LampizatorNA doesn't encourage owners to open the chassis and/or change tubes and provides no input when asked about tube choices. I suppose they expect the owners ship their DACs to Poland if/when a tube fails or needs replacement due to age.  

tubes1988, does your Amber II play Tidal MQA content? I know it doesn't process/unfold MQA content but curious to hear if it even plays that content. 

"Which Amber do you have?"

I have the original version, circa 2014.

If you notice, there are production date labels affixed along the cover and the chassis which will break if you remove the cover. If you bought the unit new, you might compromise your warranty if the labels are not intact. I personally would only consider changing the tubes if one fails or they are old beyond the warranty period.