On the super-damped Crystal Cable Minissimo at right which were simultaneously in for review, their petite dimensions and small mid/woofer had rendered them somewhat bass-shy in our >100m² downstairs space. With the mb55 in the driver's seat, this combo conspired to textural dryness, tonal compaction and an ultra-modern just-the-facts reading which had very little sex appeal. Those Dutch metal-loaded polymer boxes really begged for a higher protein diet. They wanted more meat à la pure class A Pass Labs XA30.8. In his The Audio Beat review, Roy Gregory most enjoyed them with a three-box Border Patrol parallel 300B amp to speak to the same observation.
With our resident EnigmAcoustics Mythology M1 with electrostatic Sopranino super tweeters below representing the same super monitor class, I still wanted the tube-buffered Fore Audio DAISy 1 DAC and/or our usual valve Nagra Jazz in the loop to create fully fleshed-out colours. That's coming from the XA30.8 precedent as my yard stick on these. With the cunningly voiced Teutonic Classics however, XLR direct drive off the COS Engineering D1 DAC/pre netted just the right combination of tight control with agreeable warmth in a very high-resolution context most ably led by that terrific Serbian Raal tweeter preceded by a gold/silver/Palladium-wired custom amorphous-core transformer.


I'd opted to replace these speakers' stock Stillpoints risers with Artesania Audio Exoteryc floor couplers. Due to the former's far smaller contact patches and severe speaker weight, I was worried about making dents in our soft parquet flooring. With the Spaniards' profile lower, the gap height of the Classics which defines their downfiring port's tuning had lowered too. So had bass extension. Whilst designer Rainer Weber predicted lower tautness in trade, with the Teutonic mini bricks I heard no ill effects at all. This spoke to the well-publicized benefits of low amplifier output impedance. It's an area where tube amps traditionally are weak(er) particularly when operated without any negative feedback.


Meanwhile most current class D amps propagandize loudly about extreme damping figures (4-digit numbers routinely neglect to account for speaker cable resistance and voice-coil inductance which easily takes off a zero or more). But, particularly ported alignments with ambitiously low tuning can benefit tremendously from optimized amplifier control. Without it, they often suffer boominess. This can sound exactly like triggered room modes until an amp with far superior damping eliminates the effect to show it for what it really was: under-damped port ringing, not room modes at all. My former AudioSolutions 4-driver 3-way Rhapsody 200 towers had been such a type. I only ever heard those at their best with nCore-1200 based Atsah monos. With me a more omnivorous sort who hates having to use a specific amp on a specific speaker, those thus made onward tracks to happy new owners.


One glance at the next photo explains how the Classic derives its deliberate warmth. The 7" Audio Technology midrange with its custom voice-coil former is loaded by an 8-inch rear-facing auxiliary bass radiator aka passive. Then the 10" Audio Technology woofer aims back as well. This blend of direct, bipole and omni radiation patterns administers direct and reflective/diffusive sonic elements. Their carefully tailored mix eliminates the type of lower-mid/upper-bass leanness so many modern speakers suffer. With those attributes covered, the mb55s' lack of extra in that range prevented coagulation or undue double teaming. The obvious implication? Speakers diverging from Kaiser's supremely effective recipe might prefer more pro-active electronics to compensate. The Lindemänner won't. If the speaker you leash them to is a skinny runway model, you'll want to ladle on some sauce upstream, perhaps with a tubed preamp and/or a valve-buffered source.


For some D-class duelling, AURALiC's Merak picked up the glove. These are transformer-coupled Hypex units which favour linear power supplies over switchers and apply very strategic module mods. AURALiC's modifications lower the stock UcD 400 board's 4th though 10th higher distortion harmonics whilst slightly increasing the 2nd and 3rd THD. Without calling out those choices as specific enablers—assigning such cause and effect requires parts swaps on the bench for a proper whodunnit—listening clearly determined that the Merak twins played it less dry and texturally more generous. As most things hifi, this wasn't about better or worse per se. It's always a function of interaction, completion and subtraction. More salt, less sugar? Some vinegar instead? That's where each audiophile becomes his or her own chef.

For just one size perspective, two pairs of class D monos on the Artesania Audio Exoteryc Krion amp stand vs. one pair of ~ 300-watt class AB Goldmund Telos 360 on the floor.

On my personal class D map based on many years of sampling various specimens, Pascal as implemented by Gato Audio plays it warmest and densest. Anaview by Amphion does it leanest and fastest. D.A.C.'s Maraschino is closer to the latter. ICEpower by Aura and Wyred4Sound are nearer the former. nCore and Lindemann's Helios sit somewhere in the middle. AURALiC hunkers down between them and the toastier pole. Class D sound actually stretches quite the gamut. Norbert Lindemann's take seems about as neutral as subjective auditions can sort out. After all, what exactly is neutral? None of us know! The best we can do is triangulate and approximate. The more systems and components we've heard, the more such notions get defined. But it still doesn't account for biological differences between listeners; and our inability to eliminate our own biases and preferences completely or at all. What's beyond dispute and personal likes and dislikes? The music:book 55 must operate with a very low noise floor given the easy audibility of ambient data and concomitant soundstage mapping; exerts obviously firm driver control over even more challenging loads; plays it taut, dry and crystalline regardless; and responds quite overtly to upstream changes to suggest very low self colouration.