Ever since the first ProLogue the PrimaLuna brand has earned a reputation for well-made, practical products with superb sound quality. The experience that PrimaLuna has built up over the years and its keen eye for new technology have provided the materials for an update of the DiaLogue range to Premium-level. It took some time before the amplifier was available for a review, a result of meticulous production methods and the fact that PrimaLuna makes sure that absolutely everything is ready before a product is launched. But patience is not one of my strong points, so I made a nuisance of myself by repeatedly asking PrimaLuna importer Durob for a sample. My persistence was finally rewarded and while I really liked the DiaLogue 2, the Premium is a superior amplifier.
Premium
PrimaLuna builds valve amplifiers. They have also succeeded in popularising the valve amplifier in an unprecedented way by making sure that owning a PrimaLuna is not the reserve of the technically inclined. With the Premium range they have gone a step further with innovative technology that enhances safety and reliability and also improves the sound quality. Let me try to explain some aspects of this amplifier without getting carried away with technical stuff. Adaptive Autobias is a circuit that takes care of bias, it ensures that each valve gets an optimal voltage, there is even an indicator for every power valve that lets you know when it has reached the end of its lifespan. With a single switch you can calibrate the amplifier for EL34 or KT88/KT120 valves, thereafter you can leave it alone. Not only are the valves protected but the power- and output-transformers are monitored to prevent overheating. Instead of fuses the Premium is fitted with relays, this benefits sound quality and you don't need to change fuses when a valve expires. All critical signal paths are wired with silver-plated, oxygen-free, continuous crystal (OCC) copper with a Teflon dielectric. Inside the amplifier are Takman resistors, SCR tin foil capacitors and an ALPS volume control. The power supply has a circuit that eliminates transformer hum and the amp has a heavy remote control, triode/ultra-linear switching and bypass circuitry for one input. New to both this amp and the brand is a dedicated (mono) subwoofer output.
When you check out the glassware on the DiaLogue Premium you'll see a remarkable number of small valves. There are six 12AU7 valves, three for each channel; one double triode valve for pre-amplification and two driving the power valves. Usually one valve is used as a phase splitter and driver, but every designer will tell you that a powerful drive-circuit (with more current available) and a low output impedance for the power valves equals better sound quality. This manifests in lower distortion, increased bandwidth and more linear behaviour. Tighter bass and lower treble distortion are audible benefits but traditional static measurements don’t reveal the improvements that have been wrought. The real benefit becomes clear in the dynamic conduct of the amplifier (playing music). Things like air between the instruments, a quieter background, better reproduction of harmonics, wider dynamic range and fatigue free listening can't be captured in cold figures. But these are exactly the properties that promote a DiaLogue to a DiaLogue Premium.
Beside the bypass circuitry and subwoofer output there are five inputs, one of which can be converted to MM phono. Two loudspeaker connections are available: 4 and 8 Ohms. The input switch, which is controlled by relays, remembers the last input rather than defaulting to CD on switch on. With the remote control you can choose between Ultra-Linear mode, which results in more power and more lively dynamics or the more polished Triode mode. On purchase you can choose between EL34 (32 Watts), KT88 (36 Watts) or KT120 (43 Watts) PrimaLuna valves. It’s important to point out that the gain in power is of minor importance compared to the difference in sound and character of the valves. The EL34 for example has a lush midrange but is less powerful at the extremes of the frequency band while a KT88/120 is more powerful but less subtle. The choice will mainly depend on the loudspeakers that need to be driven. Personally I prefer an EL34 in combination with a standmount loudspeaker and the KT88/KT120 for floorstanding speakers in a bigger room. But this is no ironclad rule. PrimaLuna has made things easier for themselves though, the buyer used to choose the amplifier with the corresponding valves, which meant that many different types had to be kept in stock. Now you just buy the amplifier and pick the valves you want, this is also an advantage for the customer who can choose to buy an alternative type of valve at a later date.
Setting
The PrimaLuna DiaLogue Premium was used with a variety of equipment in my house. First it was put in my smaller listening room with a Naim UnitiQute network player as a digital source, connected to a Micromega MyDac D/A-converter, which was in its turn connected to the DiaLogue with a Crystal Cable interconnect. Speaker cables and mains leads were plain Supras. The speakers that were connected to the DiaLogue were Sonus faber Venere 1.5 and PMC Twenty.23. With the Venere I preferred the EL34, the PMCs benefited from the power the supplied by KT120 valves. The second set-up was in my living room where the DiaLogue (equipped with the KT120 valves) met the Sonus faber Venere 2.5 and my PMC fact.8. The main source in this setup is a NAD M50 network player with an Esoteric D-07 D/A-converter. Ancillaries include Crystal Cable interconnects, speaker cables and mains leads, Kemp Elektroniks power conditioning and an isolating transformer. You may notice that the KT120 was my preferred valve in most instances. The EL34 worked beautifully with the small, eager Sf Venere 1.5 speaker because it doesn't master the extremes of the frequency band. I rather like the EL34 in combination with this type of speaker. However, after I switched to KT120 for the ‘small’ PMCs a "wow" escaped my lips. The Tungsol KT120 is downright marvellous in a system that has good bass extension, it makes the sound a lot more powerful and impressive with bigger dynamics. In the meantime it maintains all the good qualities of the more subtle EL34. However you look at it the KT120 was such a clear winner with larger systems and I never went back to the EL34 over the course of the review.
Listening
It is time to tell you what this amp does with music. In the smaller listening room I replaced the amplifier section of the Naim UnitiQute with the DiaLogue Premium. Unfortunately that also meant adding an outboard DAC which may obscure my verdict, but it soon became clear that the Naim although hardly less powerful than the PrimaLuna in theory, was outperformed by a considerable margin. The cute little shoe box that I happily use was completely blown away. The extra dimensions that were added and the gain in power and dynamics were downright incredible. The stereo image grew in width and height but the depth decreased. Although the Venere 1.5 was relatively happy with the Naim, the PMCs almost begged for the DiaLogue. The pair producing lots of detail and a beautiful clear sound without hard edges made for a wonderful listening experience. This demonstrates how important the amplifier is in the audio-chain. Because I had started to appreciate the DiaLogue Premium now, I moved it to the living room and connected it to the SF Venere 2.5, replacing my Audia Flight amplifiers. This resulted in a brighter sound, music was more powerful and tight but it did stick to the speakers a little and the stereo image could have been deeper. In fact I repeated my findings with the 1.5. Of course there was a considerable gain in the bass with the bigger 2.5, but this gain was also influenced by the KT120 valves. The match between the Venere 2.5 and the DiaLogue Premium was marriage, the speaker really sounded better than with the Audia Flight amps, although the latter are far more expensive. The Audia Flights tend to sound a little dark and Sonus faber has created a rather darkish sounding speaker with the Venere 2.5. But now there are two variables: the speakers and the amplifier. So, no matter how great this pairing may sound, the amplifier needed be connected to the PMC speakers that I have been using as my reference for the past two years. The balanced Yter interlink between DAC and preamplifier is the only change that has to be made; it is replaced by a single-ended Crystal Cable interconnect.
One thing becomes clear very quickly: my comment about the sound sticking to the speakers has nothing to do with the DiaLogue. As soon as the PMC fact.8 starts playing and Six Blade Knife by Dire Straits blasts into the room, localising the speakers with my eyes shut is almost impossible. It sounds absolutely great, the music bursts out of the speakers and is incredibly tight and swinging. The guitar hangs in the air and suddenly there is a drumroll from the left, far outside of the speakers. But most spectacular are the dynamic leaps the system takes with apparently effortless ease. If anyone still thinks that a valve amplifier is a dull and dusty relic from the past, listening to this amplifier will prove the opposite. The sound is immediate and quick and it’s these characteristics that give instruments an authenticity that a slower amplifier will never achieve. The initial attack of a note is crucial, a clear indication of the quality of a design. Holly Cole's voice is far more beautiful than Mark Knopfler's. Her slow Tennessee Waltz is clearly present in the listening room alongside grand piano, harmonica and double bass, all extremely lifelike. With the Venere 1.5 I noticed the vast difference between soft and loud musical passages and again I am adjusting the volume. The DiaLogue's volume control is so easy to manage, a little tap on the remote control makes the sound either too loud or too soft. The volume control on the amplifier rarely exceeds the nine or ten o'clock position, it might be a good idea to reduce the input sensitivity. Because I really like female voices it seems predictable that I ended up playing a Kari Bremnes CD, where oddly enough a man is singing on the Slattevise track. It is a nice voice that sounds very pure and lifelike in the room with Bremnes herself singing the backing vocals. The midrange, where the voices are, pleases me and I have no criticism regarding the treble, the bass is the only aspect that is a little bit lagging in direct comparison with my class A power amplifier. That is a weakness of valves. But to be fair, we must bear in mind that the Audia Flight power amplifier is twice the price of the DiaLogue Premium. Bass reproduction is not bad, it just doesn't go as deep. On the other hand it is perfectly neutral and that is of course very important.
I found that the DiaLogue Premium can also reproduce pop music and jazz rather well and that it has enough stamina to drive substantial PMC transmission line speakers. That is why I skip hundreds of albums and end up with Cecilia Bartoli’s Sacrificium. An orchestra with about the most lovely voice I have ever heard. I am no connoisseur of opera, I’m not even an opera enthusiast, but I make an exception for this lady. If you could have seen me conducting Come Nave In Mezzo All'onde, you would have burst out laughing. It’s so easy to immerse yourself in music and just enjoy the moment. The PrimaLuna invites me to do just that all the time. Another very beautiful album is Legende by Giovanni Angeleri who plays works by Pablo de Sarasate. This is a hybrid SACD of which I ripped the CD-layer to my NAS. The orchestra starts thunderously but soon passes into subtle violin-playing with a tambourine in the background. Lesser set-ups and amplifiers make the tambourine disappear even though it is almost constant. Again the DiaLogue shows exemplary behaviour: the small instrument is audible every time and is clearly recognizable as a tambourine. I almost forget to mention Angeleri's excellent violin-playing and the delicate humming of the cellos. While listening to this music I ask myself in silence why I ever abandoned valve amplification. The DiaLogue Premium has a lot to commend itself as an absolute winner. I would find it difficult to mention a handful of amplifiers that deliver this performance at this price-point. The fact that it looks refined, has everything one could wish for and is particularly safe to operate (also by my grandchildren) makes it even more attractive. In the meantime I have arrived at violin-playing in combination with a flute, so if you will excuse me, I just want to enjoy the music.
Verdict
Who am I to judge the PrimaLuna DiaLogue Premium with its KT120 valves? I can only summarize my findings after listening to it in various set-ups. In short: if I didn’t own the great Audia Flight amplifiers, the PrimaLuna DiaLogue Premium would be on top of my most wanted list. It is unconditionally recommended!
I have owned PrimaLuna products in the past and several friends have been PrimaLuna owners for years now, so I know how reliable they are and how many measures have been taken to optimize the lifespan of the valves. Up to now this is the finest PL integrated amplifier I have had the pleasure to assess. It’s recommended for every type of music be it jazz, pop or classical. Whether it’s a Big Band, a pop artist or a soloist accompanied by a large orchestra, the DiaLogue Premium reproduces it effortlessly. This amplifier is simply a hit.