Description
PrimaLuna EVO 400 Valve Power Amplifier
The PrimaLuna EVO 400 Valve Power Amplifier is a premium high-performance stereo power amplifier designed to deliver exceptional musical detail, natural tonal richness and outstanding dynamics.
As the flagship power amplifier in PrimaLuna’s EVO Series, it combines eight EL34 output valves, six 12AU7 small-signal valves, premium custom-designed output transformers and PrimaLuna’s proprietary Adaptive AutoBias technology.
With selectable ultralinear and triode operation, balanced XLR and RCA inputs, and the ability to operate in stereo or mono, the EVO 400 provides exceptional flexibility for sophisticated high-end hi-fi systems.
Premium All-Valve Amplification
The EVO 400 uses a carefully engineered push-pull valve amplifier design to provide a natural, detailed and engaging musical presentation.
With its standard EL34 output valves, it delivers:
- 70 watts per channel in stereo ultralinear mode
- 38 watts per channel in stereo triode mode
- 140 watts in mono ultralinear mode
- 82 watts in mono triode mode
The amplifier offers a choice between the greater power and dynamic authority of ultralinear operation and the alternative tonal presentation of triode operation.
Stereo and Mono Operation
One of the EVO 400’s most important features is its ability to operate as either a stereo power amplifier or a mono power amplifier.
In stereo operation, a single EVO 400 drives a pair of loudspeakers.
For more demanding high-end systems, two EVO 400 amplifiers can be configured for mono operation, with one amplifier dedicated to each loudspeaker.
This provides additional power and system flexibility.
Two amplifiers are required for a stereo system when operating in mono mode.
PrimaLuna Adaptive AutoBias Technology
PrimaLuna’s proprietary Adaptive AutoBias system continuously monitors and adjusts output valve bias.
This eliminates the need for routine manual bias adjustment and helps maintain suitable valve operating conditions.
The system also supports selected compatible alternative output valves.
Alternative Output Valve Options
The EVO 400 is supplied with eight EL34 output valves.
Compatible alternative valves include KT88, KT120 and KT150 types.
Different valve configurations provide different power outputs and musical characteristics.
Output Power by Valve Type
| Valve type | Stereo ultralinear | Stereo triode | Mono ultralinear | Mono triode |
|---|---|---|---|---|
| EL34 | 2 × 70W | 2 × 38W | 140W | 82W |
| KT88 | 2 × 72W | 2 × 43W | 145W | 88W |
| KT120 | 2 × 85W | 2 × 45W | 175W | 94W |
| KT150 | 2 × 89W | 2 × 51W | 188W | 109W |
Alternative valves are available separately and should only be fitted in accordance with PrimaLuna’s compatibility instructions.
Premium Custom-Designed Transformers
The EVO 400 incorporates substantial custom-designed output transformers engineered for wide bandwidth, low distortion and controlled bass reproduction.
These premium components are fundamental to the amplifier’s musical performance and substantial construction.
Traditional Point-to-Point Wiring
PrimaLuna uses traditional point-to-point wiring and carefully selected internal components.
Its construction includes:
- Premium custom-designed output transformers
- Substantial power supply transformers
- High-quality capacitors and resistors
- Ceramic valve sockets
- Premium internal wiring
- High-quality RCA and XLR connections
- Heavy-duty loudspeaker terminals
- Substantial ventilated steel chassis
Balanced XLR and RCA Inputs
The EVO 400 provides balanced XLR and conventional RCA analogue inputs for stereo and mono operation.
This allows integration with a wide range of compatible high-end preamplifiers.
It is particularly well suited to the PrimaLuna EVO 400 Valve Preamplifier.
Loudspeaker Impedance Matching
The EVO 400 provides multiple transformer output taps to accommodate compatible loudspeaker impedances.
In stereo operation, 4Ω, 8Ω and 16Ω connections are available.
In mono operation, 2Ω, 4Ω and 8Ω connections are provided.
The appropriate terminals should be selected according to the loudspeaker specifications and PrimaLuna’s operating instructions.
Premium Construction
The EVO 400 features a substantial steel chassis, carefully engineered internal circuitry and premium transformers.
Its 31kg net weight reflects the heavy-duty construction expected from a flagship valve power amplifier.
Key Features
- Flagship PrimaLuna EVO Series power amplifier
- Premium all-valve push-pull design
- Eight EL34 output valves
- Six 12AU7 small-signal valves
- 70W per channel in stereo ultralinear mode
- 38W per channel in stereo triode mode
- 140W in mono ultralinear mode
- 82W in mono triode mode
- Selectable ultralinear and triode operation
- Stereo and mono operating capability
- PrimaLuna Adaptive AutoBias technology
- Compatible with selected alternative output valves
- Premium custom-designed output transformers
- Traditional point-to-point wiring
- Balanced XLR inputs
- Conventional RCA inputs
- Multiple loudspeaker impedance taps
- Substantial ventilated steel chassis
- Designed for high-performance separate preamplifiers
Complete Technical Specifications
| Specification | Details |
|---|---|
| Manufacturer | PrimaLuna |
| Model | EVO 400 Power Amplifier |
| Manufacturer reference | EVO 400-4 |
| Product type | Stereo/mono valve power amplifier |
| Amplifier design | Push-pull valve amplification |
| Standard output valves | 8 × EL34 |
| Small-signal valves | 6 × 12AU7 |
| Total supplied valves | 14 |
| Operating modes | Stereo and mono |
| Amplification modes | Ultralinear and triode |
| Stereo power, EL34 ultralinear | 2 × 70W |
| Stereo power, EL34 triode | 2 × 38W |
| Mono power, EL34 ultralinear | 140W |
| Mono power, EL34 triode | 82W |
| Maximum listed mono power, KT150 ultralinear | 188W |
| Maximum listed mono power, KT150 triode | 109W |
| Valve bias system | Adaptive AutoBias |
| Frequency response | 9Hz–60kHz ±1dB |
| Extended frequency response | 8Hz–70kHz ±3dB |
| Total harmonic distortion | Below 0.1% at 1W; below 2% at rated power |
| Signal-to-noise ratio | 95dB |
| A-weighted signal-to-noise ratio | 105dB |
| Input impedance | 100kΩ |
| Input sensitivity | 1,100mV for rated power |
| Maximum gain, EL34 stereo ultralinear | 27dB |
| Maximum gain, EL34 mono ultralinear | 30dB |
| Maximum gain, EL34 stereo triode | 25.5dB |
| Maximum gain, EL34 mono triode | 28dB |
| Analogue inputs | Stereo RCA and XLR; mono RCA and XLR |
| Stereo loudspeaker outputs | 4Ω, 8Ω and 16Ω |
| Mono loudspeaker outputs | 2Ω, 4Ω and 8Ω |
| Power consumption, EL34 | 470W |
| Power consumption, KT88 | 480W |
| Power consumption, KT120 | 540W |
| Power consumption, KT150 | 550W |
| Chassis | Heavy-duty ventilated steel |
Dimensions & Weight
| Measurement | Specification |
|---|---|
| Width | 385 mm |
| Height | 205 mm |
| Depth | 405 mm |
| Overall dimensions (W × H × D) | 385 × 205 × 405 mm |
| Net weight | 31 kg |
| Shipping weight | 36 kg |
| Shipping dimensions (W × H × D) | 468 × 315 × 577 mm |
Installation Considerations
The PrimaLuna EVO 400 weighs 31kg and requires a substantial, stable equipment shelf.
Adequate ventilation is essential because the output valves generate considerable heat during operation.
For mono installations, two amplifiers must be accommodated, with sufficient space and ventilation for each unit.
Loudspeakers should be connected to the appropriate impedance terminals, and the amplifier must not be operated without a suitable loudspeaker load.
A compatible preamplifier or volume-controlled source is required.
Recommended Applications
The PrimaLuna EVO 400 is particularly suitable for:
- High-end two-channel stereo systems
- Premium valve amplification systems
- Dedicated audiophile listening rooms
- High-performance floorstanding loudspeakers
- Stereo systems using separate preamplifiers
- Dual-mono high-end amplifier installations
- Premium vinyl playback systems
- High-resolution network streaming systems
Expert PrimaLuna Advice at Riverside HiFi
At Riverside HiFi, we specialise in premium hi-fi, valve amplification, high-performance loudspeakers and complete music system design.
Our services include:
- Valve preamplifier and power amplifier matching
- High-end stereo system design
- Loudspeaker matching and demonstrations
- Turntable and phono stage integration
- Network streamer and DAC selection
- Premium interconnect and loudspeaker cable advice
- Professional installation and system optimisation
- Home cinema and smart home integration
Whether you’re building a premium stereo system or upgrading to a dedicated dual-mono amplifier configuration, Riverside HiFi can help you select the ideal equipment.
Riverside HiFi – Hi-Fi | Home Cinema | Smart Home | Professional Installation
Important: This product is a dedicated power amplifier. A separate preamplifier or suitable volume-controlled source is required. The advertised unit is one amplifier; two units are required for stereo playback when configured as mono amplifiers.
