Symphonic Line Die Erleuchtung MKII

Symphonic Line's bespoke 'Die Erleuchtung' tube preamplifier was first introduced to the HiFi community in the late 1990s. Revised MKII and MKII HD versions followed in 2006 and 2007, respectively. Symphonic Line has built some exceptional audio equipment over the years, and although I previously reviewed Rolf Gemein’s impressive RG2 preamplifier, as well as the RG9 and RG10 Reference fully-integrated amplifiers, this is my first review of the brand's tube equipment.

What can we rightfully expect from music? 

This question has captured the imagination of audiophiles and audio equipment creators since the first recordings were made. The first successful attempts at recording music date back to the invention of the phonautograph by the French printer, bookseller and inventor Édouard-Léon Scott de Martinville in 1860. Similar to a gramophone, the Phonautograph used a horn-like funnel to capture sound waves, transcribing them onto a rotating cylinder. However, it was not until 148 years later that scientists rediscovered these recordings and were able to digitise, adjust and filter them in such a way as to recreate their sound. In 2008, scientists most likely heard the voice of Scott de Martinville himself vocalising a simple melody to test his equipment. Despite the digital filters and adjustments applied, the recording revealed a limited frequency spectrum centred around the human voice and a low dynamic range. It was accompanied by lots of static and background noise.

More clearly than modern recordings, such first attempts by Scott de Martinville (and later by Edison and others) show the enormous distance that needs to be overcome between the event of the recording and the listening event. In the case of Éduard-Léon Scott de Martinville, the recording itself was so ‘sketchy’ that there was a 148-year delay until it could be reconverted. Rather than providing a faithful rendition of typical musical characteristics such as tempo, tonality, and dynamics, the inventor sings to us from a remote place that is obscured by the imperfections of the technology of his time. It is as if the dead are sending us a warning from the past, or as if the recording was found on a sound capsule from an alien spaceship. And yet, these early recordings are a living testament to the many challenges we face in faithfully recreating music events in their authentic scope and dimension from a recording.

It is therefore not surprising that my earliest memories of recorded music are of stale and hollow-sounding contraptions made from resonating plastic components. During the 1980s, the home entertainment market was flooded with cheap transistor stereo cassette recorders. The compact cassette, using standard ferric tapes, had a frequency range from 30 Hz to 15,000 Hz which sounded limiting to the human ear. If we further consider the signal-to-noise ratio of around 50dB, it is no wonder the joy of listening lay more in the still new and perplexing ability to record and play back sounds than it was in the musical experience itself. Owners of record players, or later CD players, could hope for a more faithful audio signal at the input level. And yet, most of the stereo systems available to consumers at the time used weak-chested transistor amplifiers that distorted dynamics and tonality, giving priority to all frequencies at once. There were also phase shifts and noise issues that were not evident from their specification sheets.

Phase shifts occur during the recording process when the frequencies bounce back from the room's walls and objects, and when the audio signals pass through the recording equipment's electronics. Phase shifts also occur during signal processing, amplification, and translation into sound pressure waves in the listening room. While primary phase shifts provide information about the size of the room and instruments, subsequent layers of electronic and physical phase shifts are unnatural deviations from the source signal and degrade sound quality. Similarly, the noise floor of a recording studio provides information about the venue. However, electronic and mechanical noise gathered during the recording and reproduction process is unnatural to the human ear. It eats away at signal energy and creates a sonic barrier.

It is often not the amount of noise, but its nature, that causes problems. For instance, the switching process necessary for amplification always produces distortion, but transistors produce much less than tubes. However, the human ear perceives even-order harmonics (2nd, 4th and 6th) more favourably than odd-order harmonics (3rd and 5th). While both noise sources fall into the category of electronic noise, tube harmonics are perceived as tonal warmth, whereas transistor harmonics sound sharp, dissonant and metallic. The low-power stereo compact cassette recorders of the 1980s were often driven at clipping levels, revealing another downside of transistors. When tube amplifiers are overdriven, the peaks of the waveform are rounded off gradually in a process called soft-clipping. Transistors, on the other hand, clip abruptly, cutting the audio wave flat and thus creating harsh distortion artefacts.

Our understanding is often limited by the way we depict or represent things. Scott de Martinville’s recorder sketched the musical signal onto a rotating cylinder using a stylus. While the cylinder itself was three-dimensional, the recording was made on a two-dimensional surface. Similarly, a recording engineer in the studio sees the recorded signal as a series of jagged lines moving up and down, much like the readings on a heart monitor. However, none of these representations resembles the actual sonic event. Sound is a multidimensional occurrence consisting of depth, width, height and time. Like raindrops falling from the sky, each sound has a characteristic beginning and ending, as well as a volume and speed of attack. The concept of three-dimensional sound is important for understanding how vital proportional energy is for creating a realistic impression. The fourth dimension is time, which is important for understanding the significance of time-coherence.

More than 166 years have passed since Scott de Martinville’s first experiments with recorded sound, and we have since become much better at recording and playing back sound to resemble the original event. Pioneers in many disciplines have collaborated to find the best materials, designs, and setups for each step of the process. And while “High Fidelity” became the inflationary term used for audio gear able to play back music in the household environment in a reasonable manner, the term “High End” was chosen by those who craved audiophile designs that were true to the source. Rolf Gemein was among the pioneers of high-end audio in Germany. He represented “Vernissage Laboratorium” at the inaugural meeting of the High End Society in 1981, before rebranding as Symphonic Line in 1984. Having first started crafting audio equipment in 1979, Gemein devoted his lifetime to understanding the propagation of audio signals.

Central to his research is the belief that energy needs to flow in abundance when the source signal demands it, and that poorly designed power supplies and systemic electronic resonances and reflections are the bottle necks that need to be overcome. Phase linearity, impedance matching, and handling the complete resonance circuit from beginning to end, are only some of the characteristics that give Symphonic Line gear its unique tonal integrity, timing, and dynamics. I have previously written about these traits in my articles on the RG2 preamplifier, as well as the RG9 and RG10 Reference integrated amplifiers. Although I am a careful observer and (by now) an experienced listener, I did not notice all characteristics at once. However, I did find myself transfixed from the very beginning, eager to learn more about the captivating nature of these devices.

What to expect from a Symphonic Line tube preamp?

Following my favourable reviews of Symphonic Line transistor gear, the all-tube Die Erleuchtung, in English “enlightenment” promised to be an exciting change. Henrik, a fellow audiophile from around Hamburg, had fished a well-maintained specimen out of the bay and surprised me with it. Die Erleuchtung came in similar housing to my RG9 integrated amplifier. Aranja (or grapefruit) was the fashionable finish of high-end gear in the 1990s. Whereas Henrik’s device still looked shiny and new, my RG9 looked tarnished and dull shortly after polishing it. As the RG9, Die Erleuchtung has a chassis made of a bent brass alloy of 2 mm thickness that is paired with a 10 mm face plate. At 14 kilograms, the preamplifier feels very solid and heavy, especially if we consider that the power supply comes in the form of a separate, 8.5 kg enclosure. This makes a combined weight of 22.5 kg, just for pre-amplification.

The glossy Aranja finish gives the Symphonic Line chameleon-like qualities. Similar to a tined mirror, the pre-amplifier reflects its surroundings and does not draw much attention to itself. The twelve Telefunken CC 189 tubes, whose warm glow might be interpreted as Erleuchtung, remain hidden from sight inside the enclosure. Instead, the front is dominated by four large rotary knobs with their difficult-to-read descriptions engraved on the face plate. Those familiar with Symphonic Line designs, will find the controls relatively intuitive, beginning with the four-step input source selector on the left (Phono, CD, Tuner, Aux), followed by the Tape Monitor selector (Source, Tape 1, Tape 2) to the right. As the power switch of Die Erleuchtung is located in the back of the separate power supply, there is room for a balance control on the front. This may be useful to compensate for imbalances in the setup or tubes. The volume control is the largest of the four rotary knobs and is positioned to the right.

When starting up your equipment, turn on Die Erleuchtung before your amplifier, and give the tubes some time to warm up. This is best practice for any pre-amplifier but it is especially important for tube devices in order to avoid small amounts of DC output from the tubes that might damage your equipment downstream. Other than that, all rotary knobs can be turned without having to fear any switching noise. All the knobs feel rewarding to turn and provide solid haptic feedback. I am personally a fan of stepped volume attenuators and would have preferred such an attenuator for even greater reassurance. However, I have come to understand that these are not normally found on Symphonic Line gear.

My specimen of Die Erleuchtung offered a large number of inputs and a sufficient number of outputs for most applications. All of these were of the Cinch/RCA type. I understand that XLR outputs and an MC phono stage are available as upgrades. Die Erleuchtung does not offer any digital inputs or outputs, and it does not have internal signal processing, room correction, or Bluetooth connectivity. It is simply not that kind of amplifier. If you need to integrate the pre-amplifier into a digital environment, this must be done via separate specialised equipment. The gold-plated Cinch/RCA sockets are high-quality, and there is sufficient space between them to allow for most types of high-end connector. The phono grounding screw is large enough to be adjusted by hand and is easily accessible. Connecting the external power supply requires a single proprietary cable. However, the positioning of the power switch at the back of the power supply is a bit inconvenient, as it is difficult to reach and is easy to forget. Although Die Erleuchtung requires 10-20 minutes to warm-up and sound at its best, it is not advisable to leave the pre-amplifier turned on for several days. Doing so will substantially reduce the lifespan of the tubes.

I have listened to Die Erleuchtung both at Henrik’s house, where it was paired with a large Musical Fidelity transistor amp, and in my own studio, paired with a 250 WPC Hafler amp as well, as a 48 WPC tube amplifier. The loudspeakers, too, could not have been more different: Henrik has a pair of Achenbach Trinity with AMT horns and large PA chassis; and I tested Die Erleuchtung with Martin Logan electrostatic speakers and with Polk Audio RTi A7 speakers, the latter being loaned to me by my friend Kristian. The principal characteristics of the pre-amplifier were the same in all three positions. While I could not have guessed what Symphonic Line tube gear sounds like, I now have a much clearer understanding of its dimensions. And even though I find the sound to be highly desirable, we did run into an issue that is intrinsic to the technology:

Die Erleuchtung is an all-tube design and uses eight input tubes and four output tubes, bringing the total number of tubes up to 12(!). While the original design uses matched Siemens dual-triode tubes, such as the E88CC / 6922 or ECC88 / 6DJ8, hand-selected by Rolf Gemein himself, these had already been changed to Telefunken CC 189 tubes by the previous owner. And while we did not have any complaints about their sound performance, we did notice some irregularities in the tube heating currents in the output stage and found that one tube had gone bad. In the search for possible culprits for periodic static noise on the right channel (Even when the volume control was turned off!) we examined and improved every solder joint where necessary. As the error was periodic, the failing output tube managed to conceal itself for some time. Tubes are subject to wear and need to be replaced every couple of years. With twelve specimens on board, rolling tubes can be a costly business on this pre-amplifier.

For the original owner of Die Erleuchtung the cost of replacing the tubes would have been of minor concern. In true high-end fashion, the sales price was well in the five digit figures, even then. But then, the resulting sound did not disappoint and was just as extraordinary as its price. When fully warmed up, Die Erleuchtung becomes an organic instrument rather than a technical device. It breathes the music generously into the room, freeing it in all its dimensions. For those, like me, who expected the all-tube design to exhibit the classic tube attributes, from a slightly warm colouring to a softening of sound, this pre-amplifier’s agility and directness will come as a surprise. Instead of drawing attention to itself by colouring the sound, the Symphonic Line steps out of the way to give the music its full dimension. (Not just hollow words, the FIR-Project proved this to be true. Coming up.) And, perhaps not surprisingly, it does this better than the transistor pre-amplifiers.

Compared with Symphonic Line’s RG2-MK3, which I tested in June 2024, Die Erleuchtung maintains the solid state’s exactness and timing, but it raises dynamics and instrument size to a whole new level. To my ears, Die Erleuchtung performs better with any of the tree amplifier options than the RG10-MK4, which could exhibit a slight leaning towards harshness, if the electricity and air were not perfectly clean. The RG10-MK4 also had a separate power supply and provided great dynamics, but I mostly enjoyed it on Sunday evenings, when all the conditions were perfect. Die Erleuchtung sounded great, no matter when. Whereas transistor amps can at times sound a bit lifeless, the tube design made the experience engaging and natural. Symphonic Line tends to offer exact tonal colours, and this is especially true for Die Erleuchtung. Generous, lush, full-bodied are some of the traits that come to mind.

However, Die Erleuchtung is not only perplexing on the tonal scale. It also provides great instrument separation, which is an important trait when listening to symphonic orchestras, where instruments can overlap on lesser gear. This pre-amplifier works great on classical music, but also on Jazz and other music that is based on natural instruments. I do not mean to say that it cannot play Rock and Pop, Techno, or any other style of music. It is just that its exceptional ability of separating instruments by location and tonal colour are less important in these genres that have often been mastered for car radios or club events. Even though Die Erleuchtung offers plenty of musical detail, it does not dissect the music. Instead, it keeps the narrative together in one continuous musical flow. To my understanding, this can well be the last pre-amplifier you will ever buy, for as long as you are willing to maintain it in good condition. Tube gear is a little more tricky but definitely worthy of our love.

Technical Specifications

• Type: All-tube preamplifier
• Frequency range: 2 Hz - 120,000 Hz
• Power supply transformer: 300 VA, mumetal
• Power supply capacitance: 56,000 uF
• MM phono (tube based): Standard
• MC phono (via step-up transformer): Optional
• MM/MC selection: Via rear toggle switch
• Line inputs (tube based): CD, Tuner, AUX, 2× Tape
• Line impedance: fully-automatic matching
• Fixed line output: 2x tape
• Input type (line and phono): Cinch/RCA
• Preamplifier stereo-outputs: 2x RCA/cinch
(XLR outputs optional)
• Preamplifier output impedance: 100 Ohms
• Tubes tested: 12x Telefunken CC 189
• Width: 450mm (10mm aluminum front plate)
• Height: 105mm incl. feet (>50mm ventilation)
• Depth: 380mm chassis (>100mm controls & plugs)
• Total weight: 22.5 kg (without packaging)
• Preamplifier unit: 14 kg preamp
• Power supply: 8.5 kg power supply
• Country of manufacture: Germany
• Year(s): 2006 -

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