Know Your Phono

iFi Audio has really been on a tear lately with new product introductions, and with updated variants of the company’s DACs, headphone amplifiers, and USB power source now available, it was time for their popular iPhono phono preamp to go under the knife.

Low cost phono preamps are typically either MM only with fixed 47K Ohm impedance and ~40dB of gain, or selectable between MM and MC with a ~100 Ohm impedance option for moving coils, and 60dB of gain intended to provide a compromise between low and high output MC carts. Spend a few hundred more, and you’ll likely get a few gain options between 40-60dB, and a couple of choices for MC impedance loading.

What set the original iPhono apart from its rivals was the incredible level of adjustability it offered for a relatively modest price. Gain was adjustable in four steps from 40-66dB to cover the needs of the vast majority of phono carts, and you had seven choices between 22 and 1000 Ohms for MC loading. By far the most impressive feature though was the capacitive loading option.

Unlike exotic moving coils, the humble moving magnet cartridge generally doesn’t respond to impedance – 47K Ohms is good for just about all of them – which is why pretty much every MM preamp is fixed at this level. MMs do however respond to capacitance, and the iPhono offered five choices between 100-500pF, which is more than you get even in preamps costing 10X as much.

The new iPhono2 retains the four selectable gain options, but has expanded the range all the way from 36 to 72dB, which should cover just about every cart under the sun. The capacitance and impedance loading options remain the same as before, and the latter I think represents somewhat of a missed opportunity. Frankly, I’m just not sure who really needs 22 (or even 33) Ohms, whereas a setting or two between 100 and 250 Ohms would be very welcome. The extremely popular Denon DL-103(R) for example is happiest at around 150-180 Ohms, meaning that the iPhono2 must either under or overshoot this mark.

Aside from the expanded gain settings, the iPhono2 also benefits from a host of internal upgrades, like a quieter, higher performance Class A output stage, massively increased power supply filtering, and a new “DC Infinity” circuit to eliminate the presence of DC on the output without the use of coupling capacitors. All of these improvements lead to a 3dB reduction in noise in MC mode, and an impressive 10dB reduction in MM mode. Sadly there’s no free lunch, and while the noise is down, the price is up, from $399 to $499.

So while the iPhono2 is perhaps not quite the bargain that the original was, if you’re a frequent cartridge swapper, it’s ready to work with just about any cart you can throw at it, and is definitely worth a look if you’re in the market for a new phono pre.