PrimaLuna EVO 400 preamplifier

I am an artist-painter and an audiophile. When I listen to recorded music, I sit in the sweet spot and stare at the empty space between the speakers. And while I listen, I survey and critique the soundfield, as if it were an unfinished landscape painting in my studio.

As I observe the soundstage and the apparitions of musicians within, I notice the dimensions of the recording venue (and/or microphone placement), as well as the physical energy of the entire vibrating illusion. While my mind appraises the tonal character of each recorded instrument, it simultaneously registers the tonality and viscosity of the entire soundfield. I am always aware that the stereo presentation I’m scrutinizing has two parts: an illusion and a tangible physicality. Exactly like a painting.

Also just like a painting, I’m forever considering what needs to be fixed or improved. When I change a cartridge or speakers, the change is conspicuous—like adding trees or changing the color of the sky. When I change DACs or phono stages, the change is subtler but still unmistakable—like adding aerial perspective, highlights, or deeper shadows. Switching from a transistor component to a tube component is like switching from acrylic paint (solid-state) to oil paint (vacuum tube).

Changing line-level preamps can be one of the subtlest changes of all.

Today, when I switched from the $4995 Rogue RP-7 tube preamp to PrimaLuna’s new EVO 400 tube preamp ($4499), it was like changing brands of oil paint. The new brand is still oil paint—except that, whenever I pick up the new 37ml tube, I notice its mass relative to the old 37ml tube. (Heavier costs extra but is usually better.) When I squeeze the tube, I notice differences in material density, color saturation, and viscosity—the exact differences I notice when changing preamps.

PrimaLuna’s previous preamp lineup, which has been retired, consisted of two models: the ProLogue Premium ($2199) and the DiaLogue Premium at $3199 (which I aspired to own). These two preamps, now referred to as “legacy” models, have been replaced by four new Evolution-series models: the EVO 100 ($1999), which is the same basic dual-mono, tube-rectified, choke-filtered preamp as the original ProLogue Premium; the EVO 200 ($2699), which adds a home theater pass-through; and the EVO 300 ($3699), which adds one more 12AU7 tube (for better amplifier drive) and includes a boatload of bad-ass audiophile parts, just like the original DiaLogue Premium. And now comes the new PrimaLuna flagship preamp, the EVO 400 ($4499), which includes all the aforementioned luxuries plus input and output transformers for balanced XLR connectivity.

What I like most about PrimaLuna preamps is how their exposed tubes and power-supply capacitors and their vintage-Marantz-style transformer covers make them look like classic old-school tube power amplifiers. It’s a timeless look, one that shows off the most important feature of all current PrimaLuna preamps: dual-mono 5AR4/GZ34 tube rectification. The 5AR4 is a 250ma/450VAC-capable full-wave rectifier that draws 1.9 amps of current at 5VAC (in this product, from its own separate transformer winding) and costs at least dozens of dollars to implement, while the 1N4007 solid-state diodes used in most preamps draw no current, require no additional transformer windings, and cost less than 10 cents each.

PrimaLuna’s Holland-based CEO-designer, Herman van den Dungen, apparently believes, as I do, that the sonic quality of all audio amplification is set mainly by the physical and electrical characteristics of its power supply, and that expensive, overspecified, choke-filtered, tube-rectified supplies make music sound more natural and easy-flowing than do silicon diodes and cheap chip voltage regulators. Did I mention that tube rectifiers are quieter and less colored than silicon diodes?

Each channel of the EVO 400 line stage consists of three 12AU7 medium-mu dual-triodes, two of which are wired in parallel (four triode sections total), forming a high-current cathode-follower that makes possible an output impedance of only 256 ohms—meaning it will effectively drive just about any competently designed tube or solid-state amplifier.

Most of the EVO 400’s extraordinary (52.8lb) weight comes not from its sturdy steel chassis or thick, brushed-aluminum faceplate but from the chokes and transformers required for its dual-mono power supplies—those and the six mu-metal-shielded transformers for its balanced inputs and outputs. Adding to that weight are the squadrons of fat, made-in-Switzerland DuRoch tin-foil caps; legions of super-high-quality, made-in-Japan Takman resistors; and the slick, motorized Alps Blue Velvet potentiometer, also made in Japan. All these bits are big, expensive, and generally heavier than their less accomplished counterparts. The EVO 400 measures 15.2″ wide by 8″ high by 15.9″ deep, comes triple-boxed with tubes installed, and takes only a single minute to unpack.


The EVO 400’s rear panel features six pairs of gold-plated RCA jacks: one pair for the fixed-level tape output, three more pairs for line-level inputs, one pair for the stereo HT bypass, and another as a single-ended output. There are two balanced inputs and one balanced output, all XLRs. The on-off rocker switch is on the amplifier’s left side, just behind the aluminum faceplate—itself a simple expanse that sports a volume-control knob on the left, an indicator light dead center (red means Mute, green means On), and an input-selector knob on the far right. The aluminum remote handset is both heavy (12.5oz) and stylish.

In order to convey what the EVO 400 brought to my system, I must begin by describing how the now-discontinued PrimaLuna ProLogue Premium amplifier ($2199) and preamplifier ($2199) sounded with my reference Harbeth M30.2 loudspeakers.

Driving those medium-size Harbeths, PrimaLuna’s class-AB EL34 push-pull Ultralinear amplifier made music sound effortless, direct, and emotionally accessible. As I type these words, that combo is letting Momo Wandel Soumah’s Afro-Swing (44.1/16 FLAC Fonti Musicali/Tidal) generate pure, harmonious, Technicolor pleasures. With vivo. Without strain.

This combination’s most notable weakness was a slight veiling—a misty, second-harmonic softness that muted detail and diminished rhythmic drive. I was hoping the new, more expensive EVO 400, with its extra 12AU7 driver tube, would generate a slightly brighter, more muscular presentation—with sharper focus, greater transparency, and more distinctly punctuated momentum.

I began these preamp-to-preamp comparisons by exchanging the ProLogue Premium preamp for the EVO 400 and listening to The Lord’s Prayer as spoken in unison by Revd. S.W. Sykes and the Choir of St. John’s College, Cambridge, from Evensong for Ascensiontide (LP, Argo ZRG 511). The first thing I noticed was how the EVO 400 enhanced the distinctiveness of each vocalist. Recordings of groups singing, chanting, or reciting are more interesting when each voice occupies its own unique and identifiable soundstage position; the ProLogue Premium preamp did only a good job with this kind of high-resolution spatial mapping, whereas the EVO 400 preamp specialized in image specificity. The voices were more than just clear, intelligible, and properly toned—each was surrounded by its own personal volume of air. The EVO 400 appeared to be letting extraordinary amounts of recorded information pass through it.


The chief beauty of tubes and analog is how a great LP can sometimes produce an unmistakable inkling of reality; one aspect of that is an acute sense of having real instruments and real human voices right there in my room. For me, audio is not complicated. The more real a recording feels, the more I connect with the music.

When I played the Ventures’ 1963 hit “Pipeline,” from Surfing (Mono LP, Dolton BLP-2022), with My Sonic Lab’s Ultra Eminent Ex moving-coil cartridge, Tavish Design’s Adagio tube phono stage, the EVO 400 feeding PrimaLuna’s ProLogue Premium amp, and the Harbeth M30.2 monitors, I experienced a lot more than a hint of reality. While the liner notes on Surfing were busy reminding me that a “pipeline” is the long, hollow part of a wave, the above-described system was busy making Mel Taylor’s drums and Nokie Edwards’ Mosrite guitar and Fender Twin Reverb amp sound deep-groove solid, in-the-room present, and 100% reverb-juicy.

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Durob Audio BV

US distributor: PrimaLuna USA

2058 Wright Avenue

La Verne, CA 91750

(909) 931-0219


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