In the February 2013 Stereophile John Atkinson reviews the Qol Signal Completion Stage which is added in series to the signal chain and is said to give “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.” ($3995).

After reviewing the patents and testing he concluded that it is basically a “shuffler circuit”-- that is, it takes the difference of the 2 channels, L – R and processes it before adding back to the original signal. Thus it can alter the stage width, and can do so selectively at different frequencies. He liked what it did to every recording he played through it, but the price seemed high for what it was.

[Phono cartridges are not symmetrical in their response to horizontal (mono) and vertical (stereo) signals so they can add ambience—the Decca Mark IV cartridge, which I owned was an example of this—DBH] It is now $2395.

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