Lucio Cadeddu von TNT audio bespricht den Black Cube Phonoamp

Zeitschrift:	www.tnt-audio.com März 2002
Titel/Logo:
Autor:	Lucio Cadeddu
Verlag:	TNT Audio

Lucio Cadeddu hatte bereits den Black Cube im Jahr 1998 und im Januar 2002 getestet.

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Lehmann Audio
Black Cube SE phono preamp

In a couple of years the Black Cube has become one of the most popular phono stages in the World, earning good reputation among audiophiles and getting several rave reviews from the HiFi press. Somehow TNT-Audio contributed to "spread the word" as we've been the first magazine to review the Black Cube in Europe and among the first ones the World, after Steven Rochlin's review in USA. We have followed the growth of the success of the Black Cube and its subsequent upgrades, all reviewed as soon as released. So here we are with the latest version of this little black box, now upgraded by an external massive power supply called PWX. This external power supply is available as a separate unit for upgrading ANY Black Cube in the market, even the oldest units.
Somehow this PWX answers one of the questions I raised while reviewing the mk2 or SE version of the Cube. Its bass performance was adequate but I found the first version to be punchier and gutsier. Norbert Lehmann worked on the power supply and decided to use a 30 VA toroidal transformer (10 times the original power supply capability!), filtering coils to suppress interferences from the mains, ultra-fast hi-quality rectifiers (FRED BYV27) and a good quality connection to the main preamp unit via an umbilical cord and a Neutrik 4 pole gold-plated connector.
Inside the preamp you can find, as usual, hi-quality parts such as Wima MKS caps, an OPA 2604AP dual opamp and a couple of SSM2017's. The top cover of the aluminium cabinet is dampened via a thick tar sheet.

You can just imagine how curious I was to test the "turbocharged" version of the Black Cube SE so, though seriously backlogged :-(, I gladly accepted to review this unit and to compare it to the previous ones. In the meanwhile, our Giorgio sent me a new version of our next-to-be-released DIY phono stage with battery-operated power supply so I was ready for the battle.

The new Black Cube SE + PWX has been tested for several months (Mr. Lehmann actually expected to see the review before X-Mas!) on my systems: firstly on my "B" system consisting of good quality components (not state of the art stuff), secondly on my A system for deeper investigations.

Here in Europe the Black Cube SE + PWX sells for 620 Euro though the PWX only is available for 250 Euro, more or less. This price may greatly vary abroad (and overseas!) but my comments may only refer to THIS price range.

Turbo Classic

Take a classic sports car, then add a turbocharger. I'm sure you remember the old Ferrari 208. Very nice car, indeed, at a price which was pretty unusual for a Ferrari. Nothing to complain, except that it was a bit slow, considering the brand....hence the guys at Maranello decided to add a turbocharger and the 208 started to shine!
The new "turbocharged" Black Cube is a vast improvement above the standard unit. Believe it or not, an upgraded and beefier power supply can do wonders to any HiFi component.

The first thing you can notice is that the sound is now "bigger", and not only in the sense the soundstage being wider...no, it is that kind of sound you only can get from "big" amps: powerful and tight bass and a delightful feeling as the Music is "breathing" freely in the air. And no, Virginia, this does not mean a totally "out of control" sound! Nope, everything is tighter and much more precise than before and actually the second thing you can notice is the improved (greatly improved, indeed) level of precision and detail.

Just compare this new turbocharged version to the standard one and you'll understand: no need to use golden ears and time consuming comparison tests, the difference is crystal-clear! The amount of data it retrieves from your LPs is astonishing, considering the price range, and everything is precisely placed where it should be: yes, the old Black Cube was already quite precise...this is a whole step above. The tonal balance has remained virtually unchanged, it seems just a bit brighter because the amount of informations in the high range has increased but when you focus your attention to the bass range you can't help but notice everything is playing as it should, even better than before: bass is actually tighter and even a bit deeper and FINALLY! the punch of the first version of the Cube is here again! And then some :-)
With respect to the previous versions, this newer Black Cube + PWX is much less "forgiving" with poorly recorded LPs.

Thanks to its natural musicality, it still can make bearable most of the recordings but you can distincly hear all the errors the recording engineer made. In other words, it takes you closer to the master tape and this also means closer to mistakes during the recording process :-)

Dynamics

As it always happens, a beefier and better PSU helps in the dynamics department. The turbocharged Black Cube delivers a punchier and faster sound, with that "kick" in the bass that keeps Music alive. Rock fans will have nothing to complain about :-)

This improvement does not harm the microdynamics performance, which is indeed better than before thanks to the ability of the new unit to precisely follow Music patterns (percussive or melodic) with plenty of ease. This helps improving that "live effect" the Cube had in spades since its first release. Don't search for smooth and mellow sounds here, the new Cube plays just like live: powerful, fast and gutsy...and never, I mean NEVER, harsh or edgy.

Its natural sense of pace and rhythm is still here and helps vinyl to keep that proper "timing" only top-end analogue playback systems are capable of.

Summarizing, you earn something without any loss.

Soundstaging

A wide and deep soundstage was one of the Black Cube's forte's. Now add a good amount of extra precision and focus and you get the, ehm, picture. Because of the increased level of introspection, a casual listener may find the stage a bit "forward" with respect to the older versions. This is simply a sychoacoustic effect, the increased level of details delivered to the listener somehow makes his attention to focus on them and hence on the very first (nearer) virtual planes of the stage. But, as soon as one gets used to this effect, one discovers the depth of the soundstage is still there, even deeper than before. Perhaps the background is somehow brighter, but that's all. The same holds true for the width and the height of the soundstage, slightly improved especially because of the sharpened "focus". You can more easily notice not only the contours of the instruments but even those of the virtual stage.

Finally, the comparison with our newer DIY phono stage has been quite interesting: while the Black Cube was clearly better in terms of precision, detail, tonal coherence and focus, our preliminary DIY unit did perform better in terms of soundstaging and bass frequencies sheer impact. We are working to improve it by means of a more severe caps selection ...we're planning to avoid paper in oil caps, for example. Don't ask, when ready, the design will be published on our DIY section.

Some advice

Following a good Black Cube's tradition, let me remind you this phono preamp is fully compatible with every cartridge made on Earth thanks to external switches that can modify input impedance (for MC's).

The MM section offers a standard 47 kOhm load, with 220 pF of capacitance and a sensivity of 2.2 mV with 40 dB of total gain. Max input is 63 mV. The MC section is adjustable for different loads, to suit every cart's needs: 80, 100, 470 and 47k Ohm plus a customizable slot for custom loads. The total gain of the stage is 61 dB, max input is 5.8 mV and sensitivity 210uV. The complete user's manual explains how to custom adjust your Black Cube to match your cart. The power cable is detachable thanks to an IEC socket so I suggest to use a good quality mains lead. Check our website for DIY designs if you're low on budget.

Installing the BC is easy and I'd suggest to keep both units as far as possible from the turntable (and far from each other). The umbilical PSU cable is long and very flexible so that you will encounter no problem.
On the other hand, if you want to minimize phono cable influence, you can place the preamp unit as close as possible to the turntable so to keep the cable short. The PWX unit should be kept as far as possible, though.

Warning! Running very short phono cables isn't always a good idea because cartridge response is affected by inductance and capacitance. Hence the "load" offered by 1 meter of cable could be necessary and NOT negligible. You need to evaluate this on your own system by means of A-B comparison tests.

Finally, try to use antivibration feet under the preamp and the PWX units.

Owners of previous versions can upgrade their own Black Cubes buying the PWX power supply only. The upgrade is suggested to be performed by your dealer/distributor otherwise Lehmann Audio may consider the warranty VOID. Anyway, if your soldering skills are adequate, you can do the job at home...you just need to solder the old PSU cables to a Neutrik 4-poles socket.

Complaints

The turbocharged Black Cube vastly improves the performance of standard units so there's little room to complain about its sonic performance. I'm not saying it's perfect (otherwise the newer, hi-end oriented Silver Cube would be useless :-)), it just maintains its promises, all for a honest amount of extra cash. Of course, 620 Euro ($) (here in Europe! YMMV) is still a good amount of money for a phono preamp so I'd recommend it only on analogue playback systems of fine quality, otherwise the improvement you may get from the Black Cube could result greatly reduced.

Don't expect to hook up a Black Cube to a modest turntable-arm-cart combo and then fly in hi-end business class :-)

Furthermore, if you're after good looking HiFi gear that meets the eye before the ear, look elsewhere. The Black Cube is just a black cube (ooops) matched to another black box (the PWX) via a black cable. It is nothing you can proudly show to envious friends :-) All the money has been invested on good sound research, good components and craftsmanship.

Finally, considering the 600+ Euro price tag I'd have preferred 4 (or eight) better feet instead of the ugly and useless plastic "buttons". If I remember well, for example, there exists a single BIG Vibrapod specially designed and made for the BC. Considering how cleverly priced the Vibrapods are...why not include one of these into a standard BC package?

Conclusions

I've followed the Black Cube history since its early days. Consider the first unit I reviewed was a completely black unit, even the sticker with model and brand was missing! For this reason I've always been interested to test new upgraded versions, so I can evaluate if the upgrade is "for real" or just something done to meet market's expectations.

This "third" version of the Cube is a real upgrade over the standard unit so I'd recommend it to any Black Cube owner. Also, anyone willing to improve its analogue playback system should consider auditioning the newer Black Cube SE + PWX as it still is a damn good phono preamp with an excellent quality/price ratio.