Audiozen IO - MM phono preamplifier with separate power supply unit

Io – MM phono preamplifier

IO is Audiozen's FETs MM phono preamplifier, equipped with its own separate power supply unit

concept & features

While the use of tubes can give a hi-fi device certain characteristics that are highly prized by audio enthusiasts, the choice of solid-state components is absolutely not just a fallback; so with a limited budget, excellent results for the ear (and for the pocket) can be achieved indeed. In fact, a phono preamplifier that adopts discrete components will not need the resources, in terms of components and space, that are needed instead for power supply and thermionic tubes arrangement.

There are basically three major families of solid-state semiconductors that can be used for a phono preamplifier: transistors, operational amplifiers and FETs. Since Mantra, the first solid-state phono preamplifier presented in 2009, Audiozen has always chosen the FET, for intrinsic peculiarities that make it very close to the thermionic tube.

In these years the circuit equipped with three FETs per channel designed by Audiozen has never been upset but rather improved, for the positive feedbacks obtained as well: Neuphono, Audiozen’s MC/MM phono preamplifier, is equipped with the same module together with a tube board for MC cartridges management.

IO (in English stands for “I”) is the name of this phono preamplifier, a name chosen to give it subject value to something that is normally a complement, even more when size does not help. Value that is found in every detail, from the all-aluminum cabinets, to the Jantzen polypropylene capacitors, from the fine connectors to that “plus” that is certainly not found in equipment in this price range: the separate power supply unit.
Not a cheap plug in transformer, but a space dedicated to the phono preamplifier power supply, where inside it are located the toroidal transformer and the electronic stabilizing circuit, equipped with capacitors of adequate capacity. Connection between the power supply stage and the main unit is provided by sturdy connectors and a cable that can handle much higher current than that required by the phono preamplifier.

The care taken in the design and manufacturing of IO, including the choice of a clearer, gentler silkscreening, pay off to the eye, but just as much to the ear: Audiozen’s idea of sound is far surpassed here as well, with great transparency, dynamics and control. And detail.

Audiozen IO - MM phono preamplifier with separate power supply unit
Audiozen IO - Both units are shipped inside a sturdy wooden crate internally lined

separate psu

Audiozen IO - Internal layout of both units: fine details like polypropylene capacitors and toroidal transformer
Audiozen IO - Rear panels and connectors

An audio circuit (preamplifier, power stage, phono preamplifier, etc.) can be designed carefully and with great skillfulness but without a well projected power supply all is vain.

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Audiozen IO

MM phono preamplifier
  • Semicondustors: 6 x FETs
  • Input impedance: 47 KΩ
  • Input capacity: 100 pF
  • Gain: 40 dB
  • Output impedance: < 800 Ω
  • Audio capacitors: 4 x Jantzen Standard Z-Cap
  • Toroidal transformer: 1 x 12 VA
  • Available finishes: silver & black
  • Main unit dimensions and weight: 92x54x170mm (WxHxD) – 450 g.
  • PSU dimensions and weight: 92x54x175mm (WxHxD) – 730 g.