Once upon a time, step-up transformers were all but required for the optimal handling of a low output MC cartridge’s signal. Active amplification technology was simply too noisy back then (defeating the purpose of the low output design). A step-up transformer removes active amplification from the equation & passively boosts the signal the old-fashioned way. Operating entirely apart from mains power, it’s an opportunity to silently add 21 or 24dB, which amounts to an output that’s comparable to MM cartridges (this is why a step-up transformer’s output is connected to an MM phono preamp input). Needless to say, modern active amplification has improved by leaps & bounds. MC phono preamps can apply all the necessary gain without inducing excessive noise levels… yet there remains a niche population of critical listeners who continue to swear by the performance of the step-up transformer. It’s just a different approach that, pending your low output cartridge and MM preamp, may be just what you’re after!