Just as a matter of interest, as I have 2 phono preamps (not both in use), what is the 'real world' impact of the different quoted frequency response figures? The acclaimed and reviewed CA 640p is rated at 20Hz - 50KHz, whereas the Rega fono mini is 15Hz - 100KHz. In theory, the Rega should be the better preamp, but is this actually, or necessarily the case?