OK, it took me a little longer than I expected to get back to this. Post-Super Bowl recovery, I guess (from staying up late, didn't care about the outcome).
I probably have a different situation than most -- I don't have a pre-amp in my system currently. I am using Pure Music for attenuation. In the past I have been using tube integrateds primarily, but I have been moving to SS in part to make the system more user-friendly for my wife (tubes can be intimidating for the uninitiated). When I moved to NCore amps, I made a fiscal decision that a commensurate pre-amp would have to wait.
Because the NCores are powerful and my speakers are high sensitivity, I need a good deal of attenuation under normal listening circumstances -- usually -45 dB, give or take. At that attenuation level, Pure Music (and indeed most digital attenuation) just isn't a stellar solution. I knew that going into the deal. So my current setup does not show off the other components to their best advantage. BTW, this is not to knock PM, which is a fine product -- I would venture that most software-based digital attenuation solutions have the same issues.
I had a Khozmo passive for a while and have demoed a Bent DIY passive as well. I can say with certainty that the Tortuga LDR is significantly better in my system than the Khozmo I had. Even though I haven't had it for a while, the performance difference was large. The Bent and the Tortuga are much closer in performance -- it would be unfair to make any further comparisons because I haven't had the Bent in my system for some time.
Here's what I can say about the Tortuga in comparison to the PM digital attenuation:
1. Dynamics are back in my system
2. Low-level listening no longer collapses the soundstage into a lifeless mound of ectoplasm
3. Bass performance is much improved -- it is tighter and less-one note
4. Clarity/transparency is probably the biggest improvement I noticed
5. Ability to hear the pluses and minuses of any recording is there in spades
6. Impressive speed and articulation
There is an element of "weight" that an active pre-amp brings to the table, but with most I have tried, it comes at the expense of some speed and transparency. IMHO, the Tortuga does a better job of paring away that unnecessary "thickness" in favor of a more direct, "truthful" sound. It's a trade-off I am happy to make. Factor in that I am running a single source computer-based system, and active pre-amps provide a lot more functionality (and added cost) than I really need.
In short, I was very, very impressed with the Tortuga. As Morten noted in my conversation with him, "if an LDR passive works with your system, it will really work". I agree wholeheartedly, and am looking forward to bringing one of these units "into the fold" on a permanent basis.
I hope the remaining tour members will enjoy this LDR as much as I did. If, like me, you are using significant digital attenuation, you owe it to yourself to try one of these passives. I doubt you'll go back. I thank Morten for sending this unit on tour....and congratulate him for a job well-done.
-dB
P.S. For the remaining tour users, I strongly recommend you read the Tortuga web page covering functions of the remote. I think you will find it very useful:
http://www.tortugaaudio.com/product/infrared-remote/.