Предусилители — ThivanLabs Ultimate 300

The Ultimate 300 is a ThivanLabs valve preamplifier combining a line stage built on 300B triodes with three separate phono circuits in one two-box design. The line section is a single-ended Class A design, and every internal connection is wired point to point rather than through a printed board.

Key specs that matter

Seven inputs are fitted - three RCA line inputs, one balanced XLR line input, an RCA moving-magnet phono input, an RCA moving-coil phono input and a dedicated optical phono input for DS Audio optical cartridges. Signal leaves through a single RCA socket and a single XLR socket wired to the EIA pin 2 hot convention. Line gain switches between +8 dB and +12 dB, while the phono stage provides 48 dB for MM and 68 dB for MC. Line input impedance is 100 kohm, the MM input presents 47 kohm and the MC load is selectable at 22, 47, 100, 220 or 470 ohm. Frequency response runs from 6 Hz to 50 kHz within 3 dB, maximum output exceeds 18 V peak to peak and hum noise stays under 0.1 mV. The main module measures 45 x 40 x 29 cm and weighs 24 kg, and the power supply is 45 x 40 x 15 cm at 20 kg.

Engineering and use context

Two 300B tubes drive custom output transformers developed to suit them, with two 6SN7 tubes in the line stage and a pair each of 12AX7 and 12AU7 in the phono section. Bias is set automatically, so owners can swap 300B and 6SN7 valves from different makers without manual adjustment. The detachable external supply uses several chokes, designed and tested in-house for noise filtering, along with paper-in-oil capacitors, and moving it to a separate chassis keeps transformer fields away from the low-level phono circuits. Each tube sits in a suspension mount to reduce vibration. Consumption is 95 W, and the standard 230 V version can be built for 100, 110, 117 or 240 V at 50 to 60 Hz. A remote handset is included, the casework comes in silver or black, and control knobs can be ordered in silver, black or gold.

Pairing

Because the output stage is specified for loads above 50 ohm and has a large voltage swing, the preamp can drive long balanced runs to solid-state or valve power amplifiers without difficulty. Vinyl users gain the most, since MM, MC and optical cartridges each get their own input and no outboard phono stage is needed. Plan for two shelves, as the power supply and main chassis share the same footprint.

Alternatives

The ThivanLabs X10 Preamplifier Mark II is another valve preamplifier in the current ThivanLabs catalogue.