PrimaLuna Prologue Premium Integrated Amplifier Review

July 20, 2012

I got into this hobby in the late 1960s and bought my first “serious” system in the early 1970s. Like today, I had a choice between tubes and transistors for my preamplifier and amplifier (and tuner). I listened to writers like Julian Hirsch of Stereo Review and went with transistors because of their superior technical performance. I was young and naïve and wanted the latest technology. My grandfather had tubes. I was way cooler than him. Besides, I had just spent a fair portion of my allowance re-tubing my father’s Zenith desk radio after an expensive trip to the drugstore to use their tube tester. That TV and radio repair course I took on Monday nights down at the vocational school when I was a sophomore in high school was really paying off. Well, maybe I wasn’t that cool. Just thinking about it is like an adventure on the holodeck.

I have heard many tube systems at audio shows and in audiophile’s homes, but it was not until a month or so ago when a PrimaLuna Prologue Premium integrated amplifier arrived, courtesy of tube guru Kevin Deal at Upscale Audio, that I had ever had tubes in my own listening room. Coincidentally, that was also about the time the pair of Magnepan MMG planer-magnetic loudspeakers I reviewed here arrived as well. Having acquired my first turntable in over 30 years barely nine months ago, my audiophile education is continuing apace.

The PrimaLuna Prologue Premium ($2299) is a solid, but stylishly designed, piece of gear that is right up-front about being all about tubes. There is nothing slim about it. Tipping the scales at nearly 50 pounds, the chassis is heavily weighted toward the rear where the power transformer and pair of output transformers are located. In front of them are the four pentode output tubes conjuring up 35 watts per channel, this being a push-pull design running in ultralinear mode. At the base of each output tube is a small red LED, which lights up to warn of tube failure. You can use EL34s or KT88s, or any of their common replacements. There is a switch on the right side panel to toggle your selection. When Kevin asked me if I wanted the amplifier fitted with EL34s or KT88s, I just stared at him blankly and said “Yes”. I ended up with PrimaLuna branded Silver Label EL34s, which are standard. Gold Labels are available as as option. You can even use a mixture of EL34s and KT88s and the PrimaLuna’s auto-adaptive biasing circuitry will sort things out. Thus, you are spared the ritual of setting bias with a multimeter, probes, and a screwdriver. Darn, I was hoping for something to obsess over.

In front of the output tubes, symmetrically arranged, are four smaller 12AU7 dual-triodes for the preamplifier buffer section to drive the EL34s. Rectification is handled by a diode bridge. All of the tubes are protected (as are you) by a removable, rounded, metal and glass tube cage. Since I no longer have small children in the house, I immediately removed it so I could basked in the glow of all that tube goodness.

The front panel is less than half the height of the transformer-laden rear of the chassis. You are given the option of a silver or black finish. On the left side is a large, smooth volume control. On the right is an identically-sized source selection switch. One of the inputs is marked HT. It is a home theater bypass, but not in the traditional sense. There is none of the vagueness of having to guess where the volume control is set at unity gain. There are dedicated HT inputs on the rear which simply bypass the preamplifier section altogether. Handy also if you want to use the PrimaLuna as a power amplifier only, say, if you have a DAC which handles volume control in the digital domain, like the Wadia 121 I reviewed here, the Berkeley Audio Design DAC, the dCS Debussy (review forthcoming), or a host of others. There is also is an optional MM phono stage available ($199), saving space and the cost of an extra set of interconnects. Nothing beats this kind of versatility when considering the purchase of the centerpiece of an entry-level system. The PrimaLuna also comes with nice wand-like remote control for volume and input selection as a bonus.

Around back are four pairs of unbalanced RCA inputs in addition to those for HT bypass, two sets of three 5-way binding posts which you can arrange for 4 ohm or 8 ohm output, a ground screw, and a standard combination IEC AC inlet and fuse holder. The PrimaLuna ships with a heavy duty three-prong power cable. The power switch is located at the front of the left side panel adjacent to the volume control. The manual suggests that you try both the 4 ohm and 8 ohm taps regardless of your speakers’ nominal impedance, and to trust your ears. Always good advice.

The amplifier is imported from the Netherlands but is made in China. However, flipping it over and removing the bottom panel reveals very neat, high-quality, point-to-point wiring and top-notch component selection, including Nichicon and Solen capacitors and an Alps potentiometer, so cast aside any preconceptions you may have. It immediately inspires confidence and pride of ownership. Isn’t it about time that we enter the 21st century and acknowledge that the Chinese build some very fine high-end audio gear? In fact, I would take some Goo-Gone and just remove the small Made in China sticker on the rear. What’s the point anyway?

So I connected my inputs and speakers, checked that all the tubes were firmly in their sockets and the selector switch was set for EL34s, and flipped the power switch. The tubes began to glow and the front panel indicator burned red. After a few moments, I heard a relay click and the front panel indicator changed to green, acknowledging that the auto-biasing circuit had completed its mission and I was good to go. I put on a record.

My first reaction was: “Ooo, fat”. I think it was primarily expectation bias kicking in. There is no doubt that tubes have a distinctive sonic signature, but over the course of listening, fat became lush, lush became bloom, bloom became warm, warm became laid-back, and laid-back became organic. Call it what you will, the PrimaLuna Prologue Premium got tonality right – different from solid-state – but right, in an as you imagine it kind of way. It really is quite addicting.

I did experience a problem with my unit. Sometimes one of the red bad tube lights would come on although there was no audible problem. I mentioned this to Kevin Deal, who promptly dispatched a new set of output tubes. The problem persisted and on one occasion the sound shut down altogether. Kevin shipped me a replacement unit the same day I called him and I experienced no further problems. I believe the issue lay in the auto-biasing circuit. Kevin assured me that these units are virtually bullet proof and he had only rarely experienced any problem with them. I have no reason to think otherwise.

Since we are doing old school here with tubes and planar-magnetics, I thought I would start off with an analog source, in this case, an Otari MX-5050BII-2 two-track reel-to-reel deck, which conveniently also has a four-track playback head for playing pre-recorded tapes. I spooled up a 7.5 ips recording of Cat Steven’s Teaser and the Firecat. The first thing I noted was just how well this album has stood the test of time. If one were drowning in nostalgia, I guess they might remember every album from the 1960′s and 1970′s as being a masterpiece. Truth be told, there were a lot of really bad albums made, including some by the rock stars of the day. Even the great albums, including this one, were done a great disservice by their transfer to CD in the early 1980′s, which is one reason to seek out the original LPs, and, in this case, reel-to-reel tapes.

Frankly, this tape sounds better than I ever remember the LP sounding. And the slight tape hiss you can hear between tracks is much less objectionable than the ticks and pops of an LP. The first track, a ballad called The Wind, and the fifth track, another ballad called How Can I Tell You, feature just Cat Stevens accompanying himself on the guitar. Unlike some of the other cuts on the album, he and his guitar appear dead center. His voice has a rich, creamy texture, and his guitar a large, resonant tone. He plays the songs finger-style. Without knowing that, you might think the Prologue Premium lacked detail. Instead, the lower strings ring and decay slowly, and the upper strings do not have a sharp transient response, but rather a rounded tone. Contrast that with When I Laugh and Tuesday’s Dead, where he uses a pick. Here, the guitar has a smaller, thinner sound, with the detail you would expect. He is joined by piano on Morning Has Broken, and while its image appears to shift around a bit, it is realistically portrayed, stretching between, but not outside, the speakers. Moonshadow is interesting from a production standpoint in the sense that that it harkens back to early stereo where the instruments and vocals are panned hard left and right; nevertheless, somehow the soundstage is wide and there is no hole in the middle. Of particular note is that at places throughout the song, the tambourine is shaken rather than struck with the heel of the hand and is appropriately jingly. While warmish sounding, which enhances the presentation of this album, the Prologue Premium does not homogenize the sound. It is smooth when that is called for, and crisp when that is called for. Overall, the acoustic guitar, bouzoukis, piano, bass, drums, and vocals have real substance and body. Although I am sure part of that can be attributed to the source, I am quite certain that the PrimaLuna Prologue Premium plays a significant part.

Staying analog, I slipped on Mozart’s Piano Concerto No. 21 in C, K. 467 featuring Stephen Bishop with Sir Colin Davis conducting the London Symphony Orchestra. If you have seen the movie Amadeus, this piece is instantly recognizable. Even if you haven’t, you probably know it. It opens with a rousing interplay between mass strings, brass and woodwinds, before the piano begins. The soundstage is not wide, but is deep. Instruments are delineated but do not stand out with laser-like focus. The brass has a burnished tone. The piano has a ringing quality. Right hand notes, which predominate, are not aggressive, perhaps even a bit rolled off, which is pleasant. The microphones are obviously above and in front of rather than within the piano, which would account for that tone. The second movement opens lyrically, but then is given over almost exclusively to the piano with only light accompaniment. The piano is recessed into the soundstage. You can hear the pizzicato basses and cellos clearly. The pace picks back up in the third movement. Tympani are slightly muffled, but the piano continues to stand out distinctly. I would characterize to sound as more romantic than robust, likely due in equal parts to the recording and the PrimaLuna Prologue Premium.

Moving to a digital recording, I put on the newly remastered version of the Beatles Revolver. Eleanor Rigby is likely the signature song from this album. In contrast to the Mozart recording, the sound is exceptionally clean. The soundstage, though somewhat flattened, extends beyond the speakers. Like all of the early Beatles stereo albums, instruments and vocals are panned hard left and right, and occasionally from left to right to left. The cellos are centered and anchor the song, sounding resonant with plenty of detail in the bowing. Paul’s voice, to the right, is entirely natural. In Love to You, George Harrison’s tamboura, is slightly etched, almost metallic, showing that the PrimaLuna Prologue Premium is perfectly capable of playing high frequencies with quick transient response when called on. Yellow Submarine is just fun, with the various sound effects, occupying different places in the soundstage, both left-right and front-back. Imaging is no problem for the PrimaLuna when the right material is selected. This is one great album, and the amplifier does it full justice.

Conclusion

The PrimaLuna Prologue Premium surprised me in several regards. First, it did not fit the stereotype of a lush sound with amorphous bass and rolled off highs; in other words, it was not euphonic in the extreme. It had a realistically organic sound, perhaps on the relaxed side, which means it will pair nicely with the plethora of speakers on the market which I find to be generally too bright; which is not to say it does not provide all the detail you would want when the detail is in the source. In addition, though it is rated at only 35 watts/channel, it had no trouble providing ample power to my demanding 86db sensitive Magnepan MMGs loudspeakers. It might be true what they say about tube watts being different than solid-state watts, and I am not talking here about soft-clipping. With its strong performance and versatility, it is an easy recommendation for someone adventurous enough to want to build a system around an integrated tube amplifier. And it calls out for an analog source, so grab yourself a turntable while you are at it. Don’t forget the optional MM phono stage PrimaLuna offers when selecting your cartridge.

- Frank Berryman

Contact Information

PrimaLuna USA
1042 North Mountain Avenue, Suite B PMB 406
Upland, California 91786
Telephone: (909) 931-9686
www.primaluna-usa.com
info@primaluna-usa.com

Associated Equipment

Analog Source: VPI Scout; Dynavector 20X2; Musical Surroundings Phonomena II; Otari MX-5050BII-2
Digital Source: Meridian G08; Mac Mini; Wadia 121; Halide Design Bridge and DAC HD; Pure Music
Preamplifier: Meridian G02; Meridian G68ADV
Power Amplifier: Meridian 557
Loudspeakers: Magnepan MMG; Meridian DSP5500; B&W 683; Silverline Minuet Supreme Plus
Cables: Digital: Meridian; USB: Wireworld Starlight; Analog: Mogami/Amphenol (RCA), Mogami/Neutrik (XLR); Speaker: Mogami/Audioquest (BFA/banana); Power: Volex/Marinco
Headphones: Etymotic ER-4S
Accessories: GIK acoustic treatments; dedicated 20 amp circuit; Audience aR2p power conditioner