BSG Technology QOL Signal Completion Stage - Stereophile Class A


These do a remarkable job of making imaging more lifelike. It’s easy to hear the significant change this unit makes by pressing “Bypass” on the included remote.

This ability to A-B test in real time reveals the stunning enhancement of the QOL phase expansion. You really need to hear it to believe it!

A Stereophile Class A rated device. Excellent reviews from other publications too. The unit and remote are in flawless condition.

$4000 MSRP.

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Kimber Kable - RCA Interconnects

Kimber Kable - XLR Interconnects

Kimber Kable - Power Cords

From Dagogo Review:
“The far edges of the soundstage, especially the upper and lower corners of the extremes of the soundstage, contained much more musical information than they did without the QOL. The music coming from the far left and right of the soundstage was just as prominent as it was in the middle, and the side walls of the venue could be “visualized.”

A similar phenomenon occurred with the depth of the soundstage, but in this case it also really did add significant depth to the perceived stage. To be specific, the perceived depths of the soundstage often improved significantly; an apparent depth of 15 feet became an apparent depth of 30 feet. In addition, it wasn’t just that things gained depth – the rear boundary of the recording venue actually manifested itself on many recordings. By that, I mean that you actually had a sense of the sound bouncing off the back wall. The combined effect of the improvements to the back and sides of the soundstage created an acute sense of the scale of the recording venue. This was especially the case on live recordings, and repeated itself on every recording I listened to. In some cases it was merely a pleasant improvement, but in a significant minority of cases, it was stunning.

The third thing that occurred was the emergence of instruments often lost in loud multi-instrument recordings. Cymbals, chimes, wood blocks, mariachis, tambourines and similar instruments got equal billing with kick drums, bass, piano and other bigger instruments. When I say “equal billing,” I don’t mean cymbals became as loud as the piano. Rather, I mean that instead of having to strain to hear them, they became distinct, while maintaining an appropriate relationship with the other instruments.

The QOL’s ability to reveal room cues that were previously hidden has several effects on the perceived soundstage, the most significant of which was very significant addition of soundstage depth. This increase in soundstage depth not only adds overall realism, but it can also tame forward-sounding components. My MBL 1611F has a forward perspective. With MBL’s own omnidirectional speakers, which create a three-dimensional image, this forward prospective works fine, but it can seem too close when used in a small or medium room with other components that themselves have a forward perspective, particularly speakers with this characteristic. However, with the QOL engaged, the huge depth of the presentation creates an intoxicating combination of front-of-stage vocalists/soloists with set-back accompanying performers and a clear impression of the back of the stage.

Separation and Air. There is a greater disconnection of the music from the speakers with the QOL engaged. More instruments are more clearly spread out over the depth and width of the soundstage, with fewer sounding like they come from the speakers. There is also a great sense of air within and around the soundstage, as well as an “airier” and more live feel to the music. Curiously, even though the QOL tended to slightly blur the exact placement of each performer, it nonetheless sounded more realistic because of this sense of air and separation.

From Absolute Sound
“I realize that the BSG Technologies Signal Completion Stage will be controversial, and that I’m going out on a limb with my enthusiasm for it. Frankly, it seems too good to be true. But try as I might to discover something about the sound that was antithetical to high-end values, I couldn’t. From my understanding of the technology, however, it is difficult to see how QOL makes the acoustic output from your loudspeakers more like that of the original soundfield. Is it appealing? Undoubtedly.”

From Stereophile
I liked what it did to every recording I played through it. So much of the live event doesn't make it through to a two-channel recording, and the Signal Completion Stage usefully increased stereo's sense of envelopment. "Does the product make the sound better?"—is an unequivocal "Yes."

From Audiogon
With the Qol engaged, the music takes on a natural sound and image. The soundstage becomes very wide and deep. My speakers virtually disappear. I know that is said all the time, and before the Qol I thought my set up was awesome, but with the Qol you can hear deep into the recordings. The center image is the best I have ever heard. I can now hear background singers clearer and my toe tapping has increased.

The frequency extremes are heard with an authority. What I mean by that is that they are no longer buried in the mix but sound like they were part of the intended sound, if that makes sense. Not all recordings were as hyped up as others. I guess each recording has its own reverb, echo, and different out of phase anomalies.

So the $4000 question, is it worth the money ?...

Well, if you want the deepest, widest soundstage and the wildest dynamics your components can handle, what price is that worth to you?
For me, it’s a keeper, no question.

From BSG QOL Website:
"BSG Technologies has developed a method of retrieving sonic information from audio signals that provides a realistic and complete rendering of the original acoustic event. . . . Instead of 'adding' a host of processing techniques intended to create 'effects,' we have simply found a way to extract information already present in recordings, but otherwise hidden in conventional reproduction. Our technology enables complete capture, transmission, and reproduction of such information, including elements that, until now, have remained hidden and buried in electronics, and unavailable to the listener. The result is an audio experience with fullness and richness beyond comparison and one which carries essentially all the dynamic, tonal, and spatial content of a real sonic event. . . . We call it 'qøl(tm).'"



Original Box







Yes - Power Only

Physical Condition


Working Condition


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