Experience with AMR DP-777

Hi there, I'm fairly new to audiogon, but have been assembling high-end systems for about 15 years now. Recently bought an AMR DP-777 and swapped tubes and it killed my left channel the first time. I'm no stranger to swapping tubes (in DAC's and Preamps), so I was surprised this happened. I've read some other threads that this sort of stuff has been an issue with this DAC. Of course the DAC sounds, but I have two questions/points:

1) for those of you that have experience rolling tubes with this DAC, what is your procedure to make sure it does cause some any system failure with the unit?

2) second thing is I've sent the unit in for the SE upgrade and will be able to report back to you guys the difference/improvement in sound, as I know it's sonic signature very well
I believe that there is something off in their service and commitment to their customers. I've become reticent to go the distant with them
Note: got the official heads up yesterday that the SE is ready and kits are shipping. looks to include even more upgrades than previously. looks like Avatar will start working through the backlog within 1 or 2 weeks when the receive the kits.

this could be a good thing as the specs 'sound exciting'...but only question mark is price, this was left out of the notification...curious to see if there are any last minute surprises in comparison to the original 'estimate' way back when
I received the same notice. Pricing was suggested at $1500 with a possible slight uptick. At this point in time I am disappointed, the update is a year late, is twice as much as originally suggested , and the price still isn't locked in. Not sure what a "slight" uptick means. If it is like anything else in what is quickly becoming a financially outrageous hobby it could mean a final price tag of two grand. I'm getting off this merry-go-round.
6 weeks ago the price was $1,200. Darren of Avatar needs to decide if he want to invest in a long term relationship with AMR as a real distributor and stop squeezing the market with his short term / short sighted approach (more like a bad dealer), a behavior that I have heard from many users here in the US. Maybe Vincent (AMR in UK) needs to be briefed on this. IMO the upgrade, though relevant for all those not requiring DSD, should be marketed sub 1k to stay competitive or AMR should just do the next release before mid 2015 with an upgrade path like PS Audio.
Thought I'd hop in here. Latest news is that AMR is shipping the kits this month. From what I understand, the initial price is $1500, installed. This is especially set for those who have been waiting. For people who send in for upgrade later, there MIGHT be a slight mark-up. I think Darren is waiting to see how involved the process is. He always tests before, performs repairs/upgrades, tests every input and output after and then burns in for a while to make sure everything is OK. Usually takes at the very least 2-3 days for one unit. The upgrade is now an entirely new main board, which explains the mark-up. I guess we'll see what kind of improvements it'll give in the coming months.