PrimaLuna ProLogue Premium Integrated Amplifier Review

[jdandy]

by J. Dan Daniell





An illuminating discovery is often referred to as an epiphany. So it was for me with the PrimaLuna ProLogue Premium integrated amplifier. My long standing attitude with respect to the origin of an audio manufacturing facility, in this case China, turned to dust. This well designed hand built, point to point wired integrated amplifier is quite a beauty. Designed and engineered in Holland and assembled in China to PrimaLuna’s specifications, this integrated tube amp delivers 40 watts per channel using KT88 power tubes and 35 watts per channel using EL34 power tubes. My Sonus faber Amati Anniversario’s, at 92 dB efficiency, provided a comfortable volume level with less than an estimated 5 watts.

From the outside the ProLogue Premium appears quite simple, a volume control, an input selector, and two rocker switches, one mounted on each side of the chassis. The left rocker switch is for power and the right rocker switch selects the proper bias setting for either KT88 or EL34 power tubes. In the ceramic tube sockets of this ProLogue Premium amp are four KT88 power tubes and four 12AU7 tubes. The tube guard lifts off easily with no tools required. That’s it. No balance control, no tone controls, no tape monitor loop, no speaker switching, and no additional signal paths to otherwise color a clean audio signal on its way to your speakers. PrimaLuna makes it clear by their refreshingly simple approach that the ProLogue Premium is here to do one thing, reproduce a quality musical performance in an uncomplicated fashion.

The PrimaLuna amp’s fit and finish is very good. The chassis paint job would appear right at home on a new automobile. The rear apron continues the straight forward design concept. There is an IEC power connector, five pairs of high quality gold plated RCA input jacks, plus left and right channel speaker terminals that are substantial enough to easily accommodate the large spade terminals on my Wireworld Silver Eclipse speaker cables. The speaker terminals are labeled 8 ohm, 4 ohm, and 0 ohm, the latter being the traditional negative speaker terminal. There is also a grounding terminal on the rear apron to be used with the optional moving magnet phono stage. This review sample did not have the phono stage option installed. There is also a Home Theater pass-thru function that uses a pair of the RCA inputs on the rear apron. When HT pass-thru is selected the preamplifier is removed from the signal path so your processor drives the power amplifier section directly. Most owners will find setup is easy without referring to the owner’s manual. One of PrimaLuna’s design concepts for their entire line is simple setup and intuitive control. They have certainly achieved that goal with the Prologue Premium integrated amplifier.

. . .

The ProLogue Premium has a noteworthy list of unique features, many of which aren’t seen on competitor’s products until the price point doubles or triples that of this amp. New to the ProLogue Premium integrated amplifier is PrimaLuna’s Adaptive AutoBias feature. With the flip of a single switch the bias can be properly set to use either KT88 or EL34 power tubes. In addition, the Adaptive AutoBias circuit continuously monitors and adjusts each tube’s bias, thereby accurately maintaining this critical adjustment. The Adaptive AutoBias not only extends tube life while keeping harmonic distortion at an absolute minimum, it helps maintains a quieter background.

Another useful feature that reduces stress for tube amp owners is the Bad Tube Indicator circuit. The BTI circuit works in conjunction with the Adaptive AutoBias circuit and uses four LED’s placed in the chassis, one in front of each power tube. If a tube goes bad, power is interrupted and the corresponding LED in front of the suspect power tube illuminates. This same circuit also protects the amplifier from short circuits at the speaker terminals. The power transformer and the output transformers are also protected with specialized circuits. In the event of problems like high temperature or owner error, such as replacing a tube with the power on, the ProLogue Premium automatically interrupts the power.

Included in this impressive list of features are premium internal parts like the respected Alps Blue Velvet motorized volume control. It operates smoothly and silently by hand or with the slender black anodized aluminum remote control. The speed of the motorized volume control is predictable. It is neither too fast nor too slow, so when using the remote control it is easy to tweak the volume up or down without overshot. You will also find Solen and Nichicon capacitors and a toroidal power transformer in the amplifier’s design. All of these features would be right at home and expected in a $7,000 integrated amplifier. PrimaLuna manages to incorporate all of these benefits into the ProLogue Premium integrated amp at less than one third of that price, a remarkable engineering accomplishment in my opinion.



Of course none of this would matter one bit to a music lover if the amplifier didn’t rise to its intended purpose, reproducing music in an authentic performance with a minimum of distortion and noise. With this in mind I put the PrimaLuna ProLogue Premium through a vigorous audition in my studio system. The sources were an Esoteric K-03 SACD/CD/DAC player and the Olive 04HD music server’s digital output to the K-03 DAC. Since the ProLogue Premium’s optional moving magnet phono stage was not installed I was unable to audition vinyl playback. Other gear used in this audition included Sonus faber Amati Anniversario speakers, PurePower 2000 AC regenerator, Wireworld Silver Eclipse single ended interconnects, Wireworld Silver Starlight digital cable, and Wireworld Silver Eclipse speaker cables. I used the PrimaLuna stock power cord and later introduced the Wireworld Silver Electra power cord.

When the amplifier first arrived I inquired and was informed the ProLogue Premium had approximately 50 hours on it. Since I am one of those audio enthusiasts who support the mystery of component break-in, I made the decision to allow this integrated amplifier to operate continuously with music playing for an additional 150 hours. This provided me a total of 200 hours break-in on the specialized caps and other internal components, as well as the PrimaLuna branded tubes. This may or may not be the ideal benchmark for break-in but I feel more comfortable offering my opinion of an amplifier with 200 hours on it versus 50 hours. In fact, during the first four days of listening to the ProLogue Premium I experienced a gradual reduction in edginess that existed in the upper midrange where female voices, mid and upper octave piano, violin, and horns reside. Initially I discovered that certain upper frequencies had a bite that caused me to reach for the remote to reduce the volume. To my ears this anomaly manifested itself as an exaggerated range of frequencies that drew too much attention. During the break-in period I spent as much as six hours a day listening to the ProLogue Premium, usually in the evening to well past midnight. That’s when I do my most focused listening. Each day I could hear the integrated amplifier slowly evolve, gradually developing a more balanced sonic signature. As the bump in upper midrange frequencies mellowed I began to realize an absence of listener fatigue from the listening sessions. That is always a good sign.

Further exploration revealed the ProLogue Premium integrated amp responds positively to power cord upgrades and clean AC power. On day four I swapped the PrimaLuna stock power cord for the Wireworld Silver Electra power cord, continuing to use the dedicated 20 amp circuit from the wall. What I heard with the Silver Electra power cord was a firming of bass texture and a sense of additional zest in dynamics. Listening to Stevie Ray Vaughan’s “Tin Pan Alley” from the 24Bit/88.2kHz high-res download Couldn’t Stand The Weather, the drum strikes were crisper, bass notes seemed to have added weight, and Stevie Ray’s lead guitar sounded sharper. On day five I powered the ProLogue Premium with the Wireworld Silver Electra power cord connected to the PurePower 2000 AC regenerator. After a couple of hours listening with clean AC coming from the PurePower 2000 I felt the entire performance was emanating from a darker background. The faint delicate sound of a brush dragged lightly on a cymbal, like those heard on Tord Gustavsen Trio – The Ground, ‘Colours Of Mercy”, was clearly portrayed in the background. Tord’s piano chords and single key notes diminished satisfyingly into a deep black silence. I maintained this clean power arrangement for the remaining time I auditioned the amp.



I started my critical listening of the PrimaLuna ProLogue Premium integrated amplifier in the late afternoon of day six with a total of 200 hours logged on the amp. I still find myself intrigued when experiencing the sonic signature shift of a new audio component during break-in. The sound slowly morphs from revealing certain audible inaccuracies to ultimately delivering a pleasurable and robust performance. That is how it happened to me with the ProLogue Premium integrated amplifier. I thought the amp sounded good on day one with the caveats previously mentioned, but I held out hope that additional hours would diminish the upper midrange bite I found distracting. Ultimately, as the ProLogue Premium gained hours, I was rewarded. The integrated amplifier finally replaced the upper midrange peak with a far more enjoyable presentation.

Listening to Ronnie Earl and The Broadcasters – Just For Today, “Pastorale”, my attention was captured by the resolution and clarity in Ronnie’s guitar and how weighty the deep electric bass sounded. This same Ronnie Earl recording features Beth Hart on “I’d Rather Go Blind”. Beth’s voice was gripping through the ProLogue Premium’s well focused sound stage. Playing Duke Ellington And His Orchestra – Concert In The Virgin Islands, “Mysterious Chick”, showed off the PrimaLuna’s ability to capture the essence of a live performance. The trombone’s throaty timbre was thick and earthy in the right channel, twin saxophones smooth as silk in the left channel, drums just off to the left of center and behind the acoustic double bass, and Duke’s piano in the center while a brassy trumpet interplayed with the trombone. Duke’s orchestra sounded rich and in full bloom. Listening to the 24Bit/192kHz recording of Louise Rogers – Black Coffee, “Lazy Afternoon”, her voice was suspended in the center of a convincing three dimensional sound stage. Hearing the 24Bit/96kHz high-res download of Paul McCartney – Kisses On The Bottom, “It’s Only A Paper Moon”, the recording was completely engaging, as was Diana Krall’s voice on “Temptation” from The Girl In The Other Room SACD. The ProLogue Premium reproduces the human voice convincingly. In all honestly, I find myself questioning how PrimaLuna can achieve this performance level from an integrated amplifier costing only $2299.



Commenting on the bass performance of the ProLogue Premium integrated amp, it goes deep with believable texture and authority but occasionally can sound loose in the lowest octave. On some recordings, like the Jazz After Midnight SACD, double bass exhibited an occasional tendency to sound less authentic on the lowest bass string notes. This characteristic seemed most apparent on acoustic double bass that was recorded prominently in a particular mix. Electric bass was less prone to this loss of tautness. I found the ProLogue Premium was able to resolve complex musical arrangements without difficulty, although the sensation of air between instruments and voices was not quite as spacious as I am accustomed to with my reference preamp and mono blocks. This is not to say the ProLogue Premium’s sound is congested, more like subtly compacted by comparison, as though there was less physical distance between instruments and voices.

Being accustomed to considerably higher powered amplifiers, I found myself clipping the output of the ProLogue Premium at one point while listening to Paul Hardcastle 5, “Lucky Star”. This recording has a steady rhythmic bass and strong kick drum throughout the tune. As I eased the volume up to see how loud the ProLogue Premium would play cleanly I quickly reached a point where I could hear the amplifier clipping the bass thump of each kick drum strike. That was at about 1:00 o’clock on the volume control. I quickly reduced the volume to just under 12:00 o’clock and the amplifier recovered its dynamic composure. This does not reduce my enthusiasm and overall impression that the PrimaLuna ProLogue Premium integrated amplifier represents a fine value, delivering an audiophile experience beyond its price. Owners will need to be mindful it is a 40 watt amp, not a 400 watt amp. Speaker efficiency will need to be considered, but I believe it would be an easy task to assemble a complete two channel sound system around the ProLogue Premium, even on a tight budget, that would keep many music lovers happy.



There is a lot to appreciate about the PrimaLuna ProLogue Premium integrated amplifier. If you haven’t auditioned one, you are overlooking a compact and classy integrated amplifier that rises to true audiophile sound and does it for less cost than a pair of decent speaker cables. It doesn't take an electrical engineer to admire the neat and orderly assembly of the point to point wiring and quality craftsmanship that goes into the ProLogue Premium. This attention to detail is also reflected in its performance. Do yourself a favor, audition this audio gem. Like me, I believe you will be more than a little surprised and heartily impressed.

[Masterlu]

Dan... Your gear reviews exceed any that I have read in a major publication. I say this not because this is a positive one (we all know, you call it as you hear it) but simply because you are far more thorough, detailed, and express such depth and command of your craft; you simply draw the reader in and won't let go.

I thank you for doing the review for all us here on AA, and most of all your unwavering support, participation and friendship!

[NOLG4EVR]

Excellent review Dan. You have not only done a very informative review but your writing is engaging and entertaining at the same time. I agree with Ivan, totally draws the reader in. Thank you.

[jdandy]

Originally Posted by Masterlu

Dan... Your gear reviews exceed any that I have read in a major publication. I say this not because this is a positive one (we all know, you call it as you hear it) but simply because you are far more thorough, detailed, and express such depth and command of your craft; you simply draw the reader in and won't let go.

I thank you for doing the review for all us here on AA, and most of all your unwavering support, participation and friendship!

Ivan.......What a nice compliment. I truly appreciate it. Thank you.

[jdandy]

Originally Posted by NOLG4EVR

Excellent review Dan. You have not only done a very informative review but your writing is engaging and entertaining at the same time. I agree with Ivan, totally draws the reader in. Thank you.

J.J. .......It always make me smile to know I have connected with those who read my words. Much obliged.

[jdandy]

I had a little fun with a red LED light bar and long exposures.

[Masterlu]

Originally Posted by Masterlu

Dan... Your gear reviews exceed any that I have read in a major publication. I say this not because this is a positive one (we all know, you call it as you hear it) but simply because you are far more thorough, detailed, and express such depth and command of your craft; you simply draw the reader in and won't let go.

I thank you for doing the review for all us here on AA, and most of all your unwavering support, participation and friendship!

And ditto for your Great Pics!

[jdandy]

Here is another look under the PrimaLuna ProLogue Premium's bottom cover.

[Masterlu]

A very clean design, well executed and some premium components.

[jdandy]

Originally Posted by Masterlu

A very clean design, well executed and some premium components.

Ivan.......When I pulled the bottom cover and saw the clean routing of wire, the well designed circuit layout, and the obvious care put into assembly I was pleasantly surprised.