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 These two preamps, now referred to as "legacy" models, have been replaced by four new Evolution-series models: the EVO 100 ($1999), which is the same basic dual-mono, tube-rectified, choke-filtered preamp as the original ProLogue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.

Durob Audio BV
US distributor: PrimaLuna USA
2058 Wright Avenue
La Verne, CA 91750
(909) 931-0219

ok's picture

..a poet and a great reviewer as well.

hrboucher's picture

Hold on, Mr. Reichert. Didn’t you compare the Rogue RP-7 to the Prima Luna with a different amplifier (Rogue Stereo 100) being driven by it? Doesn’t that violate a cardinal rule of equipment reviewing?

Bogolu Haranath's picture

Looking forward to the review of the new Magnepan LRS speakers :-) ........

Would be interesting to see the measurements of the LRS, if Magnepan allows it :-) .......

eriks's picture

Since it's using so many output transformers, I wonder if it has DC blocking capacitors in the output.

jmsent's picture driven by a transformer, but it looks like the single ended output is driven directly from a cathode follower through a coupling cap. My guess is that the transformer primary is directly in parallel with the unbalanced output. So yes, it's probably driven through a dc blocking cap.

Ortofan's picture

... autographing copies of his new book entitled "The Second Harmonic Sauce Diet".

If HR really wants to experience a super-scintillating sounding sense of a recording venue's space and atmosphere, then he should supplement his Harbeth 30.2 speakers with a REL T/7i subwoofer.

Bogolu Haranath's picture

Such a diet would 'fatten up' the midrange :-) ..........

Bogolu Haranath's picture

Music needs illumination :-) .......

mrkaic's picture

Primaluna makes some of the worst looking amplifiers in the industry.

They should learn visual design from Luxman or Leben. Or Quad. Or Line Magnetic. No shortage of good examples.

ok's picture

it certainly looks like a bread box.

Bogolu Haranath's picture

Music is much, much more than skin deep :-) ........

mrkaic's picture

...the amplifier here, not music in some platonic sense. :)

And this amplifier looks ridiculous, at least to me.

Bogolu Haranath's picture

I was just joking :-) .........

Bogolu Haranath's picture

Waiting for reviews and measurements of, PrimaLuna EVO tube DAC and clock, tube integrated, tube stereo and mono-block amps, in Stereophile :-) .........

Bogolu Haranath's picture

'You haven't heard notin' yet' :-) ........

mememe2's picture

"When I squeeze the tube, I notice differences in material density, color saturation". If you believe that you can squeeze a tube of paint and tell the colour saturation (without looking at the brand or price)then you need to go into rehab - but first stop drinking the kool-aid. What a load of horse droppings! And people believe what you write!

johnnythunder's picture

of a magazine. Especially Stereophile. What HR wrote and what he was implying in the context of an audio review was very clear to me. It must be sad and horribly disappointing to judge everything in the world through the closed lens of absolute objectivism.

Ortofan's picture

... drinking the kool-aid. Exposure to paint thinner vapors, in the absence of adequate ventilation, may induce vivid hallucinations.

mrkaic's picture

It’s Reichert and his ideas. Best to ignore and jump straight to measurements.

Bogolu Haranath's picture

It has about 8-bit SNR (resolution) ........ Look at Fig.7 :-) .........

Bogolu Haranath's picture

Also, look at the frequency response into different loads, Fig.1 :-) ...........

Bogolu Haranath's picture

For comparison look at the measurements of recently reviewed Bryston BP-17/3 :-) ...........

grantray's picture

I can do the same with papers and graphite. If you spend a lifetime mastering a medium through sensorial observation and use, most people who don't will call your learned abilities crazy, even though those abilities took decades to develop. For instance, those who are born blind are quite capable of hearing and smelling at levels of spacial detail the rest of us would consider superhuman, even though their noses and ears are nothing special.

Indydan's picture

I enjoyed reading this article. Well done Herb!

romath's picture

Herb - I find the meaning of the term "neutral" in audio depends on the user's perspective or tastes. For some, it's what I would consider "cool," while for others its a modest warmth like that I find comes from acoustic instruments. What I'm wondering in reading your Rogue comment at the end, is what you mean by it.

Other question: in your left-right brain metaphor, were you referring to the intellectual vs. emotional divide, however close these two were in that regard?

Jack L's picture

... the EVO 400 ($4499), which includes all the aforementioned luxuries plus input and output transformers for balanced XLR connectivity." quoted Herb Reichert.


As a classical music addict & a DIY audio designer/builder, my last thing to do is to use transformers in the music signal paths in my amps.

Why? Transformer is itself a non-linear device due to its non-linear magnetic characteristics. It rolls off both the low & high ends of the audio frequency bandwidth. It slows down the music: phase distortion, & distorts the audio signal with overloaded due to magnetic saturation.

It is noticeable when placed at the signal path front ends, e.g. input & output terminals of the preamp after magnification, e.g. balanced input/output termination with XLR connectors.

We have to know balanced signal transmission is a standard technical practical practice for recording studios, & outdoor/indoor sound performances where miles & miles long audio interconnects are used to connect the equipment. Balanced transmission using XLR connection is to eliminate noises induced into the signal transmission paths - noise-free
signal throughout.

But, but for home audios where long long run of audio signal cables does not exist, any balanced signal transmission using XLR connection therin is therefore redundant & overKILLING !!!!

As explained above, using transformers to provide balanced input/output termination only compromises the music quality due to the downside of any transformers besides spending extra big bucks to install such redundant devices.

So why BALANCED input/output termination using transformers for home audios ???????? Just to make it commercially more appealing & sellable ?

Listening is believing

Jack L