I have a 606 Mk1 and a 405-2, both serviced with the dada kits, and I find the 606 sounds significantly better than the 405-2. It’s at low volume, and the 606 just seems more natural or organic or something. The 405 isn’t bad, and there is nothing obviously wrong. Just like the 606 better. I mentioned it to the tech who did the work, and he seemed puzzled so perhaps I will have him take a look. One would think at low volume with nothing pushed, there really shouldn’t be much if any noticeable difference.Be interesting to hear how the 606 compares to the 405. Similar you’d think?