PrimaLuna Flagship Tube Power Amplifier Outputs 70Wpc and Offers One-Button Switch of Triode to Ultra-Linear Mode: EVO 400 Combines Brilliant Sound, Flexibility, and Ability to Grow with Your System
Switch from triode to ultra-linear mode with the push of a button, roll every kind of tube under the sun, and get easy, hassle-free operation with the PrimaLuna EVO 400 tube power amplifier. The flagship model of the EVO Series combines brilliant performance, incredible flexibility, and unstinting reliability in an 8.1 x 15.2 x 15.9-inch (HWD) unit whose classic looks don’t even come close to the level of sound it produces when hooked up to a pair of speakers. Since we’re on that topic, know that EVO 400 — available in stereo or mono configurations (more on the latter below) — boasts two-, four-, eight-, and 16-ohm outputs.
Loaded with 14 tubes and outputting a robust 70 Wpc (into eight ohms, stereo), EVO 400 boasts several advantages exclusive to PrimaLuna. They include Adaptive AutoBias, a smart, completely passive technology that employs sensors to monitor your tubes and makes adjustments in real time. Since it addresses “tube pinch off” at high volumes, the approach reduces distortion by a figure of more than 50 percent. Plus, EVO 400 runs its output tubes at a minimum dissipation without veering into crossover distortion. Another feature you’ll love: AC Offset Killer, which lowers transformer noise to a level you need to hear to believe — and you will, especially when you experience the elevated degrees of texture, spaciousness, black backgrounds, and natural decay that result.
Akin to its sister models, the inside of EVO 400 houses components and parts that reflect a no-compromise build-quality ethic. Massive toroidal transformers are enclosed in a metal housing and potted in a non-microphonic resin to future reduce noise and protect the windings from deterioration. This solution far out-performs C- and EI-core types in outboard power supply boxes. Also on offer: custom-made super-wide-bandwidth output transformers, the most important (and expensive) part of any tube amp. Wound in-house and beefy in size, they ensure long tube life and contribute the desired “slam” any high-end system needs to reproduce music with convincing authority and presence.
Speaking of the kind of sound that will have you up listening until the sun comes up, EVO 400 incorporates point-to-point wiring throughout — with Swiss-made, silver-plated, OCC copper with a Teflon dialect in the signal path for superb speed and transparency. Japanese-made Takman resistors, renowned for their linearity and naturalism, add to an audiophile feature set that also encompasses DuRoch tinfoil capacitors and ultra-quiet sealed relay inputs.
EVO 400 kills when it comes to airy, extended highs. But what about the trouble of dealing with tubes? Well, in addition to ensuring long tube life, EVO 400 has tube indicator lights that illuminate when a tube goes bad — eliminating guesswork, soldering, and, worst case scenario, shipping your unit back to the manufacturer. And since you can use the supplied full-size remote to switch modes, using EVO 400 is a breeze. And it's compatible with 6L6G, 6L6GC, 7581A, EL34, EL37, 6550, KT66, KT77, KT88, KT90, KT120, and KT150 tubes? Woot!
Backed by a three-year manufacturer warranty, EVO 400 awaits a risk-free audition in your home. For more information on EVO 400 or any PrimaLuna equipment, just call a Music Direct audio consultant at 312-433-0200.
“The PrimaLuna EVO 400 pre/power gets embarrassingly close to the top tier for a fraction of the price of high-end equipment… It’s the impressive centerpiece of a serious hi-fi system – one with a charm that many rivals conspicuously lack.”
—David Price, Hi-Fi News
Building a Better Monoblock
In creating its monoblock amps, the design team at PrimaLuna faced a formidable challenge: How to match (or exceed) the sonic signature of its integrated and stereo amps in a set of monoblock amplifiers with twice the power. As many designers will attest, it’s quite easy to take a step backwards when creating a more powerful amplifier.
While many designers opt for larger transformers to double the output power, PrimaLuna team decided against that approach knowing that big output transformers sometimes don’t behave as well or sound as good as their smaller brethren. Instead, the company elected to use two discrete audio channels in one chassis and paralleled them at the loudspeaker terminals. Building an amp with two output transformers per monoblock amp is almost unheard of due to one simple reason. cost.
Yet the sonic benefits are significant. This design adds a 16-ohm tap to each transformer which, when paralleled in this circuit design, resulted in an eight-ohm output. So, you now have three sets of speaker taps: two, four, and eight ohm to get a perfect "handshake" from the amps to your speakers. The ability to drive planer and ribbon speakers is unmatched.
Of course, with this approach, you risk a percentage of power from one free-running transformer pushing into the other due to output-voltage differences caused by circuit tolerances and tube aging. To counter this problem, designers developed a specific cross-coupled positive/negative feedback scheme to balance out both channels — and lower distortion in the slipstream. In addition, newly designed pre-stages improved the drive capacity to the power tubes, resulting in lower distortion levels without the need for extra negative feedback. The circuit is now inherently more stable and virtually immune to drive imbalance and the distortions that accompany tube aging.
In sum: This innovative twin-channel-summing approach with cross-coupled positive/negative feedback results in surprisingly low harmonic distortion, further pushing the performance of all PrimaLuna mono amps.
- Power Stereo Ultra-linear: 70 watts x 2 (EL34), (8Ω, 1% THD)
- Power Stereo Triode: 38 watts x 2 (EL34), (8Ω, 1% THD)
- Power Mono Ultra-linear: 140 watts (EL34), (8Ω, 1% THD)
- Power Mono Triode: 82 watts (EL34), (8Ω, 1% THD)
- Inputs: 1x Stereo RCA, 1x Stereo XLR
- Outputs: 4, 8, & 16 Ω (stereo); 2, 4, & 8 Ω (mono)
- Freq. Response: 9Hz-60kHz +/- 1dB, 8Hz-70kHz +/- 3dB
- THD: < 0.1% @ 1W, < 2% @ Rated Power
- S/N Ratio: 95 dB, 105 dBA
- Input Sensitivity: 1100 mV
- Input Impedance: 100kΩ
- Power Consumption: 470 watts (EL34), 480 watts (KT88), 540 watts (KT120), 550 watts (KT150)
- Standard Tube Complement: 6 - 12AU7, 8 - EL34
- Dimensions (WxHxD): 15.2" x 8" x 15.9"
- Weight: 68.2 lbs