Solid State Preamp Reviews

Sidebar 1: MBL Chief Engineer Jürgen Reis

Jürgen Reis, 59, whom John Atkinson respectfully describes as "an engineer's engineer," joined MBL in 1982, when the company was three years old. After improving the original MBL preamp, he designed MBL's first three-way speaker system, the MBL 101, in 1986.

As Reis's work continued, he found time to sing baritone/bass in the award-winning Hanover Choir, play guitar in a rock band, and serve as a recording engineer. With time for only one serious recording project per year, he currently records the superb ensemble Concerto Köln for Berlin Classics. For fun, he also records local orchestras, including "Orchester im Treppenhaus" (Orchestra in the Staircase).

"Listening to real instruments while you set up the microphones is a totally different story than listening at a mixing desk," he told me. "If I set up the microphones in the wrong position, I can mix endlessly and still not get a good result." The parallels with optimal system setup are clear.

Jason Victor Serinus: I already have dCS Rossini and EMM Labs DV2 DACs with excellent volume controls in my all-digital front end. What are the advantages of adding a preamp?

Jürgen Reis: If the output stage and volume control of the DAC are a perfect match for the amps, you do not need an analog preamp in between because you cannot beat a perfect match. But since you do not know, I hope that the design of the N11 matches the amps very well. I know that the N11 matches the D'Agostino Momentum monoblocks very well, but I haven't heard the Progressions long enough to know if the N11 will work as well with them.

If the tonal characteristics of the components match and balance each other, then the sound is more fluid. For example, if you have a power amp that is a little bit shy in bass and you compensate with a preamp that pushes bass a lot, you create a balanced sound, but you lack some fluidity. If both have the same characteristics, then they match better together. That's what a good preamp can do.

Serinus: Do most people use the N11 with other MBL gear?

Reis: Yes. But it's fine for you to use it in a different system because you are experienced with setup. If you have a system that, over the years, you've tuned to the sound you like, there will not be any addition that will give exactly what you want without retuning. You must play a little bit with cable or threads or feet to find a new balance. It's difficult for me to write a step-by-step guide of what to do, because unless you've experimented in advance, you have no idea what the tonal characteristics are for each component you add or change. You must change piece by piece.

Serinus: Could you elaborate a bit more on how you develop and tune your components?

Reis: I begin with a sound in my head. In the case of the N11, the sound was different from the Reference Line, different from our Corona Line, and different from the [previous, now-discontinued] Noble Line. Then I use my knowledge to create a schematic that I think will work, put this into a printed circuit board, and conduct first measurements. When I am happy with the measurements, then I begin to listen and "tune" the parts. I use different types of resistors and capacitors from different manufacturers. I also tune the isolation of the internal cabling and adjust how it's laid out. Then I remeasure and continue the process until I am happy with the specs and the sound.

Serinus: Given my reference components and 16 × 20 × 9 room, do you see me as a Noble customer or a Reference customer?

Reis: In between. You have a Reference-customer character, but your digital front end and cable tell me that you're more like a Noble Line customer. It's not about the price of the cable; it's about the sound. For you, I would mix it a little bit up, with maybe a Noble Line preamp and cable that would better integrate it in your system. If you had the Reference preamp, you might need to change the rack or feet a bit to match your taste.

I've had a bit of fear that you've set up your system and maximized your sound with a preamp that has, for example, a gain of 8dB or 10dB. In that case, even if my preamp is "better," the Unity Gain feature will not satisfy you. You may have to change something such as the feet to generate the sound that will make you happy.

Serinus: Do you tune your products with specific cabling, footers, and power conditioners?

Reis: For product development, cables I've known for a long time is a fixed variable that I do not want to change, because I know how those cables sound. I mostly use Wireworld Eclipse for speaker and interconnect cabling. Regardless of whether there is "better" cable out there, I know the Wireworld Eclipse sound very well, and it works all the time, at every show, in every setup. For digital cables, I use mostly AudioQuest Diamond for USB, SPDIF, AES, and LAN. Again, it works very well at every show and every setup.

Ultimately, cable choice depends on the room, the taste, and the racks. When I visit a customer and talk to them about their taste, I listen to some music, evaluate their room, and am then able to recommend a cable upgrade that matches their wants and needs.

I like the Finite Elemente Emperor rack a lot—it provides a good foundation—but the choice strongly depends on taste, room, and cabling. I also use the rounded-tip RDC cones from Clearlight Audio; their composite granulate is stable but not resonant. If I want a bit softer sound, I use Mpingo Discs from Shun Mook.

Every MBL product uses double-shielded transformers. Unless someone's AC is not stable, I would start without power conditioning. We have electrostatic shields in our components to prevent common mode coupling and electromagnetic shields to prevent differential mode coupling. All our products are measured to withstand HF frequency and do not radiate HF noise. But many/most customers either have different products in their setup or have some electrical disturbance that a power conditioner can help. They have to try and decide.

Serinus: As a recording engineer, do you find that the preferences and predilections of conductors and musicians and audiophiles match what you are trying to achieve, or do the preferences diverge and require compromise?

Reis: I've had lengthy discussions with conductors because of what they feel and how they hear. To achieve the right tonal characteristics, we have to speak a lot. Musicians create some emotions in their brain or body, and they want to experience these same emotions during playback. Because listening to real musicians triggers different areas in the brain than listening to phantom sources [speakers or headphones], good engineers have to engage in some trickery to help the brain feel similarly. The sound isn't the same from an acoustical standpoint, but you have to convince the brain that it's similar.

I rarely make compromises in dynamic range—the worst I've ever done was on a death metal recording with a dynamic range of 11. If you look at mass-market pop and rock, you will not find a dynamic range of 11; most mass-market productions have DR around 5 or 6. Mostly, I stick with mastering engineer Bob Katz's suggestions in this regard. When people ask me to record, they know I do not make compromises in dynamic range.