HIFICRITIC APR | MAY | JUN 2022 REVIEW | CHRIS KELLY A question of EVOlution THE EVO 400 ISNT CHRIS KELLYS FIRST ENCOUNTER WITH PRIMALUNAS AMPLIFICATION, BUT IT LOOKS SET TO BE A LASTING ONE, SO MUCH DOES HE FIND TO ADMIRE Regular readers of HIFI CRITIC may recall that, back in issue 59, I wrote a review of the PrimaLuna EVO 300 integrated amplifier. To save you digging it out I was absolutely smitten with it. It was my first foray into valve (tube if you are in other parts of the world than the UK) amplification since I owned an Emille K70 back in the 1990s, and it reignited my fascination for this distinctly 20th-century technology. Actually, it did more than that: ever since the EVO 300 and 6 12AU7 valves in the preamplifier, all of which are here, whatever loudspeakers or sources I have branded with the PrimaLuna name. The hand-madehad here to review I have wondered to myself how chassis is constructed of heavy gauge, fully vented they would have sounded with the PrimaLuna. Then. steel which sports a five-coat paint finish, which looks in the manner typical of an obsessive, I started to gorgeous and adds to the feeling that one is dealing wonder how much better the 70 watts per channel with a genuinely high-end product. EVO 400 would sound compared with the 40 watts The valves all sit in ceramic sockets and everythingof the EVO300. I watched the YouTube explanation within the chassis is point-to-point wired, the onlyof the EVO 400 by Kevin Deal of Upscale Audio in printed circuit board inside the chassis being for the California, who is the US distributor of PrimaLuna AutoBias system, which constantly monitors the products but who is also involved in the design and condition of each valve and which makes owning and specification of the PrimaLuna products. Eventually using the amplifier no more onerous than a solid state my desire to hear the EVO 400 became too strong a device. For someone who is new to the world of valves to ignore, I gave in and asked Absolute Sounds, this is an absolute boon, removing as it does the need for the UK distributors if they would be kind enough to for the user to bias the valves by hand. If the system sends one to Kelly Towers for review. Detects that there is an issue with a valve it illuminates The EVO 400 as shipped from the factory carries a red LED in front of the valve holder so that the user complement of 8 EL34 valves in the power amplifier can replace the failed or failing valve.There are three rocker switches on the chassis. On the left-hand side (as seen from the front)is the power on/off control. On the right-handside, one switch allows the user to switch theauto-bias system from the EL34 setting to theKT setting. What does this mean? In the world of valve aficionados, there is an activity often called tube rolling, which means swapping one typeof valve for another. Thanks to the PrimaLunaauto biasing system, a user can remove the supplied EL34 power valves and install one of the KT Series - 88, 120 or 150 for example. Each of these offers an increased power output of 72, 85 or 88 watts per channel in the Ultra Linear mode, as well as subtly changing the sound characteristicsof the amplifier. I do not have a stash of alternative valves so I have not tried this. One word of caution, according to PrimaLuna the KT150 is too largeto fit under the supplied removable safety cover which helps to prevent the unwary (children, pets, partners etc) from touching the valves, which areof course very hot indeed when the power is on. The valves are all installed at the factory, with a protective sleeve over each of the EL34s. The third rocker switch, also on the right-hand side, allows the user to turn the EVO 400 into a headphone amplifier. This is not some marketeers afterthought, using (as some designs do) an inexpensive op amp to drive the headphones. It diverts the main amplifier to headphone use instead - so the EVO 400 doubles as a very high-quality valve headphone amplifier too.On the back of the chassis, there are two sets of loudspeaker binding posts, with 8ohm and 4ohm outputs, a pair of RCA outputs for attaching a subwoofer, with a mono/stereo switch alongside, and then 7 pairs of RCA input sockets, including one marked HT, which allows the EVO 400 to be integrated seamlessly into a home cinema set-up if that is required. There is no provision for using balanced XLRs here. The last feature on the back is the IEC mains power input socket. Fuss-free design The front panel is very fuss-free. Towards theleft is the rotary volume control, which is an ALPS analogue device. The centre has a small cluster of LEDs. At power up bright red lamp signals that the amplifier is warming up, and this switches to green once all the valves have reached operating temperature, which takes about a minute. Just above this light is another LED which glows red when the amplifier is in its default Ultra Linear mode or green when the Triode mode is selected via the supplied all-metal remote control (the only way that this can be done). On the right-hand side is the input selector dial, with a green LED showingwhich input is active. There is an audible click when inputs are changed, explained in part by the fact that only one input relay is ever open at one time, which helps to minimise any crosstalk between inputs another example of PrimaLuna not cutting any corners to ensure optimum performance from the amplifier. As the manual explains, All PrimaLuna power transformers include the PTPTM (Power Transformer Protection) circuit. When the power transformer overheats due to environmental circumstances, overloading or some problem in the unit, aninternal thermal switch breaks the primary, allowing the unit to cool down before harm is done. After its cooled, contact is restored and if nothing is broken, the amp will repower and function properly. This is an important feature and is reassuring my Emille K70 was badly damaged when a family member used it when I was away on business and forgot to switch it off after the listening session. The only optional extra which can be ordered with the EVO 400 is a moving magnet phono stage, a solid state device which sits externally on the bottom of the chassis. It was not fitted to the review unit so I cannot comment on it. I suspect that most purchasers will already have their preferred external phono amplifier but it is good that PrimaLuna has the provision if required. When the unit arrived, even the strappingyoung courier was huffing and puffing as he brought the box from his van to the front door. The shipped weight is about 36kg, which puts it on the edge of what I can cope with single-handed, and even once unboxed it still weighs an impressive 31kg, but I was just about able to manhandle the heavy beast onto my venerable Quadraspire XL rack, and set about connecting the system. TelluriumQ UltraBlackII speaker cable, running from my Harbeth C7ES3XDs was plugged in, using the 8Ohm option. For inputs, Audioquest Earth from the GoldNote PH10 phono stage and Audioquest Yukon from the Yamaha CD-S3000 SACD/CD player was plugged into the inputs marked Aux1 and Aux2. The cable from the REL305SE was plugged in and that switch was set to mono. Finally, the optical cable for the television was plugged into the DAC on the Yamaha. A Shunyata Research Delta NR2 mains cable, fed from the same companys Hydra mains block was plugged into the IEC socket. Powering the unit on can only be done via the side-mounted rocker switch. Doing so one hears the EVO 400 coming to life as the electricity flows around and brings those 14 glass tubes to life. Once it is on the EVO 400 is silent, and even with an ear hard up against the loudspeakers there is no noise at all Sound Quality I was expecting great things from the EVO 400 and wasnt to be disappointed. Even during the first few days, when it was bedding in, it produced a sound that was even better than my memory of its smaller sibling, but my intention remained to play a few silver discs but not to sit and listen, so I loaded my Analog Productions SACD of Pink Floyds Wish You Were Here, pressed play and walked out of the room.For about five minutes, as it turned out: thesound coming from the room drew me back inand there I stayed, playing several different pieces of music until Mrs Kelly returned from work. Even after a couple of hours, it felt as if the amplifierwas getting fully into its stride, and that evening we watched an action film, the EVO 400 handling the huge dynamic range of the soundtrack really well, with dialogue coming through with terrific clarity and realism. There was a real sense of being enveloped in a three-dimensional aural world, even though it was all emanating from a single pair of loudspeakers. (At this point the REL was plugged in but not powered on). The next few days were really an orgy oflistening, mostly through the Linn/Gold Notevinyl system, and extended sessions were quite unfatiguing. I played my usual selection of test albums, and each of them sounded more involving than they have for a long while. Instead of playing one track, I found myself listening to the wholeside of an album, then turning the record overand listening to the second side. What valve amplifiers do especially well is project the midrange frequencies in such a way that vocals and guitarsreally stand out from the mix, which suits my typical music selections very well. However, the EVO 400 also produces very high-quality bass frequencies too - bass guitar and acoustic bass come through with great pace and tonality.Listening to Osibisas 1971 album Woyaya onmy original MCA UK pressing, the contribution of their bassist Spartacus R is vividly portrayed without ever dominating proceedings or sounding too big and bloated. In fact, this album proved to be a great way to hear just how accomplished the EVO 400as a musical communicator, from ethereal flutes to pounding drums I was swept along by the sheer joy de Vivre of the players. Pace, rhythm and timing This is not the woolly, warm, soft valve sound of myth and legend au contraire, it has the much sought-after pace, rhythm of the timing of the finest solid-state alternatives, but with that magical richness only a thermionic device seems to produce. Changing the mood, Gary Karrs masterfuldouble bass is wonderfully captured on the Cisco Firebird pressing of En Aranjuez Con Tu Amor, on which he is accompanied on piano and organ byhis long-term collaborator Harmon Lewis. This2005 recording captures the sound of these two gifted players beautifully, and through the EVO 400 provoked a very strong emotional response in this listener. The final track, Samuel Barbers Adagio For Strings, was absolutely spell-binding. Ive started to enjoy jazz in the last few years,though Im still exploring and learning, and through the EVO 400 I started to revisit my rather modest collection of recordings on vinyl. A recent purchases Christian McBride and Inside Straights Live at The Village Vanguard, a 2021 double record release onthe Mack Avenue label of gigs at the renowned New York venue back in 2014. The final track, StickMove, features a lot of interplay between McBrides double bass and the drums of Carl Allen it sounded epic. Drums dont always sound this realistic but through the EVO 400 and Harbeths it felt as if one was in the venue with the band. Ive overheard audiophile conversationssuggesting valves are only good for relatively easy-on-the-ear acoustic music, and that reproducing heavy rock is best left to powerful solid-state amplifiers. If those gentlemen could have joinedwhen I played the 2015 Parlophone release of Iron Maidens The Book Of Souls I suspect they would have had to recant: turning the volume up, Bruce Dickinsons voice came through loud and apparent, with his bandmates in hot pursuit. This system rocks. All this listening was done with the amplifier in its default Ultra Linear mode, but now it was time to experiment with the triode option. A press of the Top button on the nicely weighted remote control and the LED changed from red to green, indicating that the amplifier was now operating in the lower power mode. I spun up the 2014 Jimmy Page remastering of Led Zeppelin II, which I dont play very often because I find it a little too strident, and the EVO 400 in Triode mode reduced this to such an extent that I really enjoyed it. Switching back and forth between Triode and Ultra Linear as the record was playing was interesting: in the latter mode it was still more enjoyable than I remembered it, but the Triode option was even better. After that, I switched between the two modeson numerous albums, and there are some which definitely are more pleasurable in the lower-powered Triode setting. My early 1970s Rolling Stones albums all seemed better played that way, as did the Doors on SACD - LA Woman became almost a different album, with the warmth and intimacyof Jim Morrisons final recordings seeming to gain inpoignancy and realism. Other albums did not benefit from leaving Ultra Linear, but the great thing with this is that the listener can experiment to their hearts content with the on-the-fly switching. Vivid in-head pictures Although Im but a very occasional user of headphones, I did bring out my closed-back Audioquest NightOwls to see whether the EVO 400 could sound as good through as it does through loudspeakers. It does, to the extent that I chose this mode of listening for several days when I was home alone. Theres an inky black background until the music starts, but once it does it creates a vivid sound picture within the head. I had enjoyed LA Woman through the loudspeakers now it became even more intimate, and here again, being able to switch to Triode at the touch of a button was really pleasing. If you are a regular headphone listener, the EVO 400 will serve you very well indeed. Given that the EVO 400 is loaded with 14 valves,it does give off a fair amount of heat, but Ive usedit for extended listening sessions for several weeks now and it hasnt missed a beat. It will be more expensive to run than a solid state alternative, but its only switched on when I want to listen and always switched off at night. With plenty of air around it on my open rack, the heat doesnt seem to affect the components on the shelves above. I also tried the 4ohm loudspeaker outputoption (having started with the 8ohm on the advice of the distributor). There was not a huge difference in sound quality but for me, the 8ohm option sounded slightly better so thats what I stuck with. I gave my smaller loudspeakers, the Harbeth P3ESRs, a run out with the EVO 400: these, although a very consistent 6ohm load rightacross their frequency range, are only rated at 83.5dB efficiency, the EVO 400 had no problem driving them to impressive volume levels without any audible distortion. In fact, this made for an extremely enjoyable listening experience. Conclusion I have been fascinated (my wife might say obsessed!) with music for as long as I can remember and was lucky enough to be a teenager in the 1960s, so I have records in my collection that I purchased as far back as 1965. And like many of my generation, my aspirations were to get a job, buy a house and a car, find a partner to share them with and then to buy a stereo system on which to play my records. In those far-off days, valves were much more common than they are today then came to the widespread use of transistors and other solid state devices, and valves became side-lined a throwback. But they didnt go away and a few keen audio designers kept the faith. PrimaLuna was founded in 2003 by the Dutch audio engineer Herman Van Den Dungen, whoalong with a coterie of others, set out to bring to market twenty-first-century versions of amplifiers using valve technology, and in the almost two decades since the brand has grown in terms of sales but also reputation, garnering many (forgive the pun) glowing reviews along the way. The EVO 400 is the logical culmination of all that experience and knowledge and is quite simply a magnificent single chassis implementation of the valve amplifier designers art. Is it perfect? Of course not Id love to have a couple of pairs of balanced XLR inputs, for example but theres very little Id change. However, itll be interesting to try different valves in it, although the current crisis with Russia has pushed the cost of replacement valves to an all-time high, as well as severely limiting supplies, so that may have to wait a while. When I started writing reviews of hi-fi equipment a few years ago a good friend of mine, who knows me too well, warned me that this could prove to be an expensive past-time. Ive been very fortunateto have had many fine audio components pass through my listening room, from racks and cables, through source components and amplifiers to loudspeakers, and I have tried to do them justice by painting word pictures for those who take the time to read them. That done, the items have been boxed up and returned with gratitude, for just like you, I find this an endlessly fascinating hobby. But this time, dear reader, the amplifier isnt being boxed up and going on its merry way. I have arranged to buy it, because I think Id miss it too much once it was gone. I can think of no stronger recommendation than that.
