PrimaLuna EVO 400 Tube Power Amplifier

PrimaLuna EVO 400 Tube Power Amplifier – eight output valves, 70–89 W and triode/ultra-linear by remote

The flagship of the EvoLution power amplifier range

The PrimaLuna EVO 400 Tube Power Amplifier combines every premium feature in the EvoLution range with eight output valves and the heaviest transformers. In ultra-linear mode it delivers 2× 70 W stereo with EL34 valves — with KT150 valves, output consequently rises to 2× 89 W. In mono mode the figures become truly remarkable: up to 188 W with KT150. Since Swiss Made wiring, Takman resistors and AC Offset Killer are all present, the EVO 400 is therefore the most completely specified valve power amplifier PrimaLuna makes.

Eight output valves and a damping coefficient of 7

By contrast with the EVO 300's four output valves, the EVO 400 uses eight — consequently doubling output power and raising the damping coefficient from 4 to 7. As a result, it has greater grip on the loudspeaker and delivers more powerful, more controlled bass than any other model in the range. Since the high damping coefficient moreover suits loudspeakers with complex impedance curves, the EVO 400 drives a wider range of designs with authority. Jeff Dorgay of TONEAudio notes that his PrimaLuna has played music for seventeen years without a hitch — a testament to the reliability the brand has built over decades.

Triode/ultra-linear by remote and full connectivity

The triode/ultra-linear switch is operated via the included Slim remote — no manual intervention at the amplifier required. Since triode mode reduces output to 2× 38 W (EL34) or 2× 51 W (KT150), the amplifier consequently sounds softer and more emotionally direct in this configuration. Balanced XLR inputs alongside standard RCA connections allow connection to virtually any preamplifier or DAC. Speaker taps cover 2, 4, 8 and 16 ohms, furthermore ensuring compatibility with virtually any loudspeaker. Tube rolling is moreover straightforward thanks to Adaptive AutoBias and the high/low bias switch.

Recognised worldwide as a reference

The Absolute Sound awarded the EVO 400 Tube Power Amplifier in both 2025 and 2026. Hi-Fi News named it an Outstanding Product, and a HK Award confirms its reference status. Above all, the EVO 400 is the choice for those who want the absolute maximum from valve power amplification — in stereo or as a monumental monoblock delivering 140–188 W per channel.

Specifications

• Type: valve power amplifier, push-pull, switchable ultra-linear/triode, stereo/mono
• Output power UL stereo: 2× 70 W (EL34) / 2× 89 W (KT150)
• Output power UL mono: 1× 140 W (EL34) / 1× 188 W (KT150)
• Output power triode stereo: 2× 38 W (EL34) / 2× 51 W (KT150)
• Output power triode mono: 1× 82 W (EL34) / 1× 109 W (KT150)
• Valves: 8× EL34, 6× 12AU7
• Valve compatibility: EL34, KT88, KT120, KT150
• Inputs: 1× stereo RCA + XLR, 1× mono RCA + XLR
• Outputs: 2, 4, 8 & 16 ohm speaker taps
• Damping coefficient: 7
• Triode/ultra-linear: yes, via Slim remote
• Swiss Made wiring: yes
• Takman resistors: yes
• AC Offset Killer: yes
• XLR inputs: yes
• Adaptive AutoBias: yes
• Point-to-point wiring: yes
• Bad Tube Indicator: yes
• Remote control: Slim remote
• THD: <0.1% @ 1W
• SNR: 95–105 dB A-weighted
• Frequency response: 8 Hz–70 kHz, ±3 dB
• Dimensions: 405×385×205 mm
• Weight: 31 kg

Frequently asked questions about the PrimaLuna EVO 400 Tube Power Amplifier

How does the EVO 400 differ from the EVO 300 power amplifier?

Eight output valves versus four in the EVO 300 consequently means significantly more power — 2× 70 W versus 2× 44 W in ultra-linear mode. Furthermore, the damping coefficient is higher (7 vs 4) and the transformers are heavier. Both models share the same premium components including Swiss Made wiring, Takman resistors and AC Offset Killer.

Which valves are compatible and how easy is tube rolling?

Compatible types are EL34, KT88, KT120 and KT150. Since Adaptive AutoBias and the high/low bias switch handle all adjustments automatically, tube rolling requires no test equipment or technical knowledge. With KT150 valves, output rises to 2× 89 W stereo or 188 W mono.

Can the EVO 400 be used as a monoblock?

Yes — since each unit has a built-in stereo/mono switch, two EVO 400 power amplifiers can be configured as monoblocks, each consequently delivering 140–188 W per channel depending on valve type. This makes the EVO 400 pair one of the most powerful valve monoblock combinations available at any price.