phase control on BAT VK pre amps


Does the phase control on the BAT series preamps have any appreciable or detrimental effects on music that is not recorded out of phase? I don't hear any difference with phase light on or off?? Anyone experience different effect?? Also, is it better to put pre in standby mode when not in use or leave on constantly? What's the difference??
wwchange
The following CD has a test that will enable you to tell if you can actually hear the Wood Effect. It also contains test for proper sound stage(left and right imaging), the LEDR test, etc: (http://www.amazon.com/Chesky-Records-Sampler-Audiophile-Compact/dp/B000003GF3) Notes on the Wood Effect here: (http://mariobon.com/Glossario/Fase_Assoluta.pdf) LEDR info here: (http://www.stereophile.com/features/772/)
You will only hear the effect of inverting the phase if you have a recording with only 2-3 mics in true stereo.

50% of recordings are out of phase anyway, so this can get really tricky.
The Chesky disc has two demos, in which phase is reversed. The first with one trumpet(actually two tracks, one reversed). The next with a full jazz band, which they reverse the phase on, without telling you at what point. My son and I both noted the exact moment of reversal, different days, no prior discussion. I own a number of recording(CDs and vinyls) that I have marked for reverse phase playback. As Ralph mentioned; there are many more in which no differences will be noticed.
"My son and I both noted the exact moment of reversal, different days, no prior discussion. I own a number of recording(CDs and vinyls) that I have marked for reverse phase playback. As Ralph mentioned; there are many more in which no differences will be noticed."

Keep in mind that the Chesky CD is made for demos. Most likely, they selected tracks that emphasize whatever quality they want you to hear.
"Keep in mind that the Chesky CD is made for demos. Most likely, they selected tracks that emphasize whatever quality they want you to hear." GEE, Ya think? Chesky recorded those tracks, and reversed the phase, to demonstrate the Wood Effect, and enable one to see if they can discern it. That WAS the point!