Фонокорректоры — Bryston TF2-20

The Bryston TF2-20 is the 20 dB version of the TF-2, a fully passive step-up transformer that raises the signal of a moving coil cartridge before it reaches a moving magnet phono stage. It contains no active parts and needs no power supply, so it adds gain without its own electronic noise floor.

Key specs that matter

This gain is the stock transformer fitted to the TF-2. Bryston lists sensitivity of 0.5 mV for this version, and its guidance points it at cartridges with an output of 0.4 to 0.5 mV or higher, while a 0.3 mV cartridge can work with either gain option. Output impedance is 4.71 kilohm. THD is below 0.001% measured at 1 kHz and -60 dBu. Response is down 0.5 dB at 20 Hz and 0.1 dB at 20 kHz, and common mode rejection reaches 120 dB at 60 Hz. The case measures about 145 mm wide, 65 mm high and 210 mm deep, and the unit weighs roughly 1.4 kg. The faceplate is available in black or silver. US list price was USD 1,195, and a later US price of USD 1,495 applies to either gain version.

Engineering and use context

A moving coil cartridge produces only a fraction of a millivolt, which is too little for an MM input on its own. The transformer converts that small voltage to the level such an input expects, using wide bandwidth windings rather than an extra transistor gain stage. For this model the maker's recommendation covers MC cartridges whose coil impedance is under 45 ohm and notes that a load of 100 ohm is a good value for most MC designs. The rear panel carries RCA sockets in and out and a separate ground terminal for the turntable lead. Because the device is passive, cable runs should stay short and the unit should be placed away from mains transformers, which can induce hum in the windings.

Pairing

The TF2-20 sits between the tonearm cable and an MM phono input, either a standalone stage such as the Bryston BP-2 MM, which draws power from an external PS-3 or MPS-2 supply to keep noise low, or the phono section built into an integrated amplifier or preamplifier. Medium output MC cartridges are the target, and owners of very low output models will find more headroom in the higher gain option.

Alternatives

Bryston's TF2-30 uses the same passive chassis with 30 dB transformers for cartridges of around 0.3 mV or less.