Phonostages — Bryston TF2-30

The Bryston TF2-30 is the higher gain build of the TF-2 step-up transformer, intended for low output moving coil cartridges that cannot drive a moving magnet phono input directly. The optional higher ratio transformers replace the standard parts, while the passive circuit with no active components and no power supply stays the same.

Key specs that matter

Gain is 30 dB. Sensitivity is 0.1 mV, so cartridges producing 0.1 to 0.2 mV are the main target, and Bryston notes that 0.3 mV models can use either version. Output impedance is 4.85 kilohm, slightly above the 4.71 kilohm of the 20 dB build. Distortion stays under 0.001% at 1 kHz and -60 dBu. Low frequency roll-off is 0.5 dB at 20 Hz and the top end is down just 0.1 dB at 20 kHz. Common mode rejection is 120 dB at 60 Hz. The enclosure is roughly 145 mm wide and 210 mm deep and weighs about 1.4 kg. Height is quoted as 57 mm, and the front plate comes in either black or silver. Bryston can also fit step-up transformers inside its BP-2 MM/MC phono preamplifier, which is the route for owners who prefer a single box. That preamplifier handles low, medium and high output cartridges. The standalone TF-2 was listed at USD 1,195 in the US at one point and USD 1,495 later, with the same price for both gain options.

Engineering and use context

Higher transformer ratios bring more voltage gain but reflect a lower impedance back to the cartridge, so this build is advised only where the coils measure less than 5 ohm. For loading, the maker's guidance is that 100 ohm suits most moving coil designs. Stepping up with windings rather than with extra transistors avoids the hiss that a high gain active stage can add at these tiny signal levels. Connections are RCA in, RCA out and a ground post that takes the earth wire from the turntable. Keeping the interconnects short and the unit clear of power transformers helps prevent induced hum.

Pairing

It feeds any MM phono input, including Bryston's own phono preamplifier or the phono section inside an amplifier, and the combination then provides the total gain a very low output cartridge requires. Turntables whose arm cable carries a separate earth lead make full use of the dedicated ground terminal.

Alternatives

Bryston's TF2-20 is the stock lower gain version of the same transformer, aimed at medium output moving coil cartridges of about 0.4 mV and above.