So after a recommendation from Ron Hedrich at Marigo, who is now a PPT dealer, I took the plunge and had the Gate installed. My system already has some pretty extensive power conditioning (dedicated 40A 240V line with SR treated breaker and ground isolation -> Torus WM75BAL wall mounted (300lb!) isolation Tx -> two SR PowerCell 12 UEF SE Conditioners -> a mix of SR Galileo SX and AQ Dragon PCs) so the installation was non-standard. We ended up putting it between the floating neutral incoming to the Torus wall mount and one leg of the balanced primary. I’ve had it in place for a week now and while still seeing some small incremental changes believe I have a fair handle on things.
Anyway you're all wondering what did it do? The answer is complex. What the Gate does (in this system context) is subtle but actually pretty important. First up the Gate does nothing for most of the usual areas like lower noise floor, more dynamics etc etc that I got from things like the various generations of SR conditioners I've been through, or Power Cord upgrades.
Instead what the Gate delivers is a sense of integration and seamlessness between component parts of instruments or voices, or between players in an ensemble. What do I mean by this? Take something relatively "simple" like a piano note or a sharply struck chord on a steel strung guitar. Many systems will render the broad outline of the note and let you hear the different combinations of lower frequencies (the fundamental) and the overtones and leading edges but often they don't quite come together, it's almost as if the sound is made up of many different instruments playing at once. With the Gate somehow all of these constituent parts integrate in a new way that seems much more realistic. Piano in particular is a good test where the initial percussive impact of hammer on string, the tone, and the decay are all of a gestalt. The same is seen on vocals where differences in miking and vocal technique are much more apparent.
There is a possible downside however. What I’ve noticed across multiple recordings I know well is that the perceived soundstage has changed – in many cases becoming less deep with more of a forward, even “wall of sound” presentation. In other cases and other recordings a deep soundstage is however still apparent. My hypothesis as to what is going on is that the cues we use to decode soundstaging are about small timing differences between different frequencies in the mix i.e. we are able to interpret a slight delay between line A and B as A being further away. With the Gate removing reproduction driven delays some "artificial" perceived depth vanishes. But by the same token other more subtle cues such as height become more apparent. So instead of the system imposing a sonic soundstage signature across every recording you hear only what is on the original disc.
The types of effect I am describing are closest in my experience to what I found when applying grounding solutions – so those familiar with the benefits of grounding may know what to look for.
Net net for the cost of a power cord these days the Gate is a no questions asked benefit to a well configured system. I have no opinion on whether the Gate could substitute for other power conditioning approaches – that’s not how I am using it in my system and the benefits it brings are fundamentally different from what I get from traditional conditioning and isolation.