Step-Up Transformers are a serious option for anyone who owns a Moving Coil (MC) cartridge, as they allow both the cartridge and the phono stage to work to their fullest potential.
Due to the technology they use, MC cartridges have very low output, often around one-tenth of a Moving Magnet's (MM) output, which means they require more gain from a phono stage in order to be played at normal listening levels through your hi-fi system.
Where phono stages, as part of their signal amplification, will have a constant resistive input impedance, Step-Up Transformers have an input impedance that is frequency-dependent. Step-Up Transformers are also passive (i.e. not mains powered) devices, which also reduces the chance of external electrical forces impacting the cartridge's low output signal. The result of a Step-Up Transformer's design is that they are able to amplify the MC output level and produce less harmonic distortion as the frequency rises - which is the opposite effect of a phono stage. This results in a cleaner electrical signal and more dynamic sound performance from the cartridge in a wider, deeper soundstage.
How to set-up a Step-Up Transformer
Step-Up Transformers still require a phono stage in the system, for "active" amplification and RIAA equalisation, so they are connected between the turntable output and a phono stage. However, the phono stage will now need to be set for an MM-type signal, typically at around 5mV/47kΩ. This reduced gain requirement allows the phono stage to perform to its fullest potential, for greater sound performance.
Step-Up Transformers are often seen as niche devices, but Ortofon produce a range of options - each of which are suited best to a particular cartridge line - offering both affordable and high-end solutions. One thing is clear, and it's that Step-Up Transformers are a must-audition accessory for any serious vinyl audiophile.
