Anyone HEARD the qol 'signal completion' device?

I heard the QOL device today while visiting with Dave Weinhart; of Weinhart Design in Los Angels; he had it after his EAR pre; and hooked up to EAR tubed amps; driving Magico M5's; source was Sooloos server running thru Star-tech dac, and I brought my own familiar music; and engaged the QOL on and off at my request.
I was an initial skeptic; but now I'm a convert; with this uber system; the sonic depth; detail, staging, decay, and 'meat on bones' improvement was not subtle. I plan on placing an order; that's how certain that what I was experiencing was real; and would help me enjoy the music in my own home system even more. While on one hand it does strike people as 'snake oil', or simply pressing the loudness button of an old stereo; it does make a significant sonic improvement; without causing harm; at least to my ears. I guess I echo the glowing endorsements of folks who have actually heard one. It would be nice if the price of admission went down; but I am now a believer.

It's not snake oil, but it's not something revolutionary either. From the paucity of info available from the manufacturer it appears to be a mid/side processor. Read this article for an understanding of the M/S process. I believe Alan Blumlein described this in the 1930s.

A summary of M/S is that it breaks down a left/right stereo signal into a mono mid channel and 2 side channels. The stereo image size can be increased or decreased by how the side stereo signals are mixed back into the mono mid signal.

The Manley Backbone is a mastering studio preamp that has built in M/S processing. The Rupert Neve Field Editor is an outboard M/S processor that offers extensive control in manipulating the stereo width and depth.

Being that M/S processing has been extensively used by mastering engineers for decades and is also readily available as DSP plug-ins in most recording/mixing software, I don't see why high end, audiophile oriented manufacturers would want to incorporate the QOL process into their products.

I hooked mine up today. Put it between a Cary preamp and Cary amp. Very impressed. I did not need a lot of time with it to tell if it was doing something positive or not. I used a sound meter to make sure I was playing the tracks at the roughly the same volume to compensate for the 2 db in gain with it activated. Just more detail, air, 3Dness. Sounds good even out of the sweet spot. One big plus is I can listen at a lower volume levels because everything is there. Before the QOL, I found myself turning up the volume to hear details better in a lot of tracks. Now, everything seems more fleshed out, and no need to turn up the volume, which is good because I want save my ears. Great addition to my system, I'm keeping mine.

So what is going on here? In Europe, we're not easily able to access a unit for trial so are observing others' experiences.
I get the feeling that the equivalent of a change in soundstaging, increase in presence (akin to increase in volume/gain) and revealing/emphasis on ambient cues is leading to most listeners' enjoyment of the unit. Whether this is an alteration of the signal is a matter of opinion, as is whether it is an actual improvement over plain unaltered stereo.
I've just installed a SpatialComputer Black Hole bass attenuator which has integrated bass from my Zu Definitions 2's. This has also opened up my soundstage leading to more ambient cues becoming apparent etc. I would call this an improvement, although unlike the QOL, it isn't in the chain of the signal before it gets to the speakers.
The interesting quetion is whether this perceivable change is an improvement still over a period of time. Time will tell, I guess.

The QOL is no different than any other device which is non-necessary in the signal path (i.e. passive networks on cables, power conditioning/filtering, etc). It offers potentially increased sense of separation between instruments and a more 3-D sounstage, but at the cost of an absolute reduction of clarity/definition due to the component and extra set of cables being added to the rig.

It is not a 100% additive device, but is also subtractive in nature (as are these others referenced above). Every potential owner/user must determine if the effect it offers is worth more than the electronic overburden it imposes upon the rig. Just as responses will vary in terms of whether a DAC with level control should be used with an outboard preamp, so also reactions/conclusions will vary in terms of the efficacy of the QOL.

To date the only devices I can recall which have been virtually 100% additive without a noticeable subtractive effect has been Opamp upgrades and certain brands of cables.

The QOL imo does have efficacy in terms of manipulating the soundstage and perception of spatial relation and level of instruments/voices as they are heard in a recording. Some will conlcude it is an absolute necessity to achieve SOTA sound, while others may disagree. I believe the dividing line in regards to personal acceptance of it will be determined by whether one accepts the additional (i.e. additional, though non-necessary) signal processing or less.

I am not interested in arguing my observations, and YMMV.