Boosting delicate low-level signals from a moving coil pickup cartridge is one of the most difficult challenges in audio, because the gain required is huge. The slightest problem with noise or RF is emphasised to an alarming degree.
It gets worse: things like circuit layout are hyper-critical. Slight errors in track routing or grounding, that would pass virtually unnoticed at line level, can produce significant losses of sound quality or noise with a phono stage. MFA's Moving Coil Step-up transformer is not a complete phono preamp, but the all-important first-stage.
It needs to be partnered with a phono-stage featuring RIAA equalisation and a standard type MM input sensitivity/impedance. Since nearly all modern phono stages include the option of a solid-state MC step-up device, you may wonder what's the point of this MFA device? Aren't you buying something you already have?
The simple answer is – yes; but that misses the point. Being (in effect) a passive device, a step-up transformer produces virtually no noise. It is, therefore, especially effective when used with ultra-low output MC pickups – say, those with an output voltage of less than 100uV.
While ultra-low output cartridges are usable with solid-state step-up preamps, you're on the borderline so far as noise and gain are concerned. An LP cut at a low volume level may require an increase in gain that reveals excessive preamp hiss.
The MFA is a fairly minimalist device, with a single set of inputs and outputs and a three-position switch that offers a choice of 14, 20, or 26dB gain, plus an impedance switch.
When correctly configured and optimally positioned, the MFA should be completely hum-free. But it is very sensitive to ground loops and stray hum fields.
So you need to take care with wiring and placement. Screened interconnects are essential.
Stevens & Billington TX-103 transformers are employed and these are claimed to have a virtually flat response from about 5Hz to beyond 100kHz. Copper wire is used for the coil windings, with the option of silver at a higher cost.
The casework is made from brushed aluminium and the unit has a classy look and feel.
High-quality, Swiss-made ELNA rotary switches, with silver contacts are employed and internal cabling is via 0.6mm silver-coated, single strand wire with PTFE insulation.
At £1,695, the MFA MC transformer is hardly inexpensive. And that's just for the copper-coil version; for those able to spend more, there's a variant with 99.99 per cent pure silver coils, priced at a cool £2,695!