Предусилители — PrimaLuna EVO 400-3

The EVO 400 is the flagship valve preamplifier of PrimaLuna's EVO series, from the Dutch company known for hand-built, point-to-point wired tube electronics. It shares the dual-mono, tube-rectified platform of the EVO 300 but adds balanced XLR connections and higher-grade parts, including Swiss silver-plated wiring, Takman resistors and PrimaLuna's AC Offset Killer circuit.

Key specs that matter

Inputs are two pairs of balanced XLR, three pairs of RCA and a home theatre bypass, while the outputs comprise single XLR and RCA pairs plus a tape feed. Gain is 9.7 dB. Frequency response is 18 Hz to 38 kHz within 1 dB and 12 Hz to 75 kHz within 3 dB. THD is below 0.5% at 2 V and signal-to-noise is 93 dB (98 dB A-weighted). Input sensitivity is 650 mV, input impedance 220 kohm and output impedance 256 ohms. The tube complement is six 12AU7 and two 5AR4. It is 385 mm wide, 205 mm high and 405 mm deep, at 24 kg and 61 W consumption.

Engineering and use context

PrimaLuna gives both channels an individual potted toroidal transformer, regulation and 5AR4 rectifier tube, so the preamplifier is effectively two mono units in one chassis. Tube rectification gives a slow, controlled rise of the high-voltage supply. The AC Offset Killer circuit removes the DC component present on many mains supplies, which otherwise causes transformers to hum. A motor-driven ALPS Blue Velvet pot handles level, and input switching uses sealed relays placed at the rear connectors, which isolate unused inputs from the active one. Point-to-point wiring uses Swiss-made silver-plated copper, capacitors are Nichicon and DuRoch polypropylene and tinfoil types, and the tube sockets are ceramic. The chassis is heavy-gauge steel with a hand-polished five-coat finish. SoftStart limits thermal shock to tubes and components at power-up, and the PTP circuit opens the transformer primary if it overheats, restoring power once it cools. The optional PhonoLogue MM phono stage mounts in a fully shielded internal compartment connected to the bottom plate. A heavy metal remote is supplied. The XLR inputs and outputs make it possible to run balanced cables from a DAC through the preamplifier to the power amplifiers, which rejects noise picked up along longer runs.

Pairing

The balanced outputs suit PrimaLuna's EVO 400 power amplifiers, which also have XLR inputs, and any power amplifier with input impedance of 10 kohm or more. Valve sources see a light 220 kohm load at every input.

Alternatives

PrimaLuna's EVO 300 preamplifier uses the same dual-mono tube-rectified platform with RCA connections only.