We are slowly moving away from toroidal mains transfromers for numerous reasons, one of them being lesser potential in sound quality. EI core enable us to use higher grade of core laminations such as cold rolled, grain oriented silicon steel (M6 or HiB M1 or Super HiB M0). These higher grade materials saturate faster, cost much more and have the potential to make the sound more transparent. In contrast to that most commercial torroidal designs use non grain oriented silicon steel cores, which are less expensive and saturate less but also tend to sound less revealing.
