Lucio Caddeddu von TNT Audio bespricht den Lehmann audio DAC+

Zeitschrift:	TNT Audio Nov. 1998
Titel/Logo:
Autor:	Lucio Caddeddu
Verlag:

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Lehmann Audio DAC+: D/A converter and preamp

Product: Lehmann Audio DAC+ D/A converter and preamp
Manufacturer: Lehmann Audio
Approx. price: 1,995 $ (check their site for EU Countries price)
Availability: authorized dealers or directly from the Web

TNT-Audio has already reviewed an audio component from this German HiFi brand, namely the famous phono preamp Black Cube, so for further infos about the company I invite you to read that review or to browse their brand new web site.

The DAC+ is a very original HiFi component, it is a D/A converter including a small minimalist hi-quality preamp with 4 digital inputs and 1 aux analog one that can be used to connect the output of a phono preamp, for example. No (analog) tape out outputs are available (just 3 digital outputs), no tone controls, no balance, nothing at all. Just a solid brass volume knob and a switch to choose between the 4 digital sources and the analog one.

More precisely, the DAC+ has 4 digital inputs: 1 optical (Toslink), 2 coaxial (gold plated connectors), 1 XLR balanced (Neutrik connector with gold plated pins). Then it has an analog input (which accepts signals up to 9 V RMS) and 3 digital outputs: 1 optical, 1 coaxial and 1 XLR balanced. Digital dubbings are not affected by the selection of the analog input.

Taking a look at the inside of the DAC+ (see the picture below) you'll find a very precise layout and a large use of very hi-quality components: a Noble volume control, WIMA MKS caps and Analog Devices op amps, a massive toroidal transformer and an impressive power supply section.

The D/A conversion section uses a Crystal 24 bit DAC (CS4390), different from the old 20 bit chip (CS4329) which equipped the DAC+ reviewed by the friends at Soundstage, for example.

The DAC+ offers a pletora of pretty unusual features: the owner can customize his DAC+ to suit his needs, for example: the volume control can be bridged so that you can use the DAC+ as a standard D/A converter, the output caps can be excluded from the signal path, if your power amplifier has a DC offset filter in its input stage and the gain can be lowered by 6 dB (default output at full digital scale is 4 V RMS).

Take a look at the excellent layout in the picture below.

The cabinet of the DAC+ is just a plain solid black metal box (43 x 21.5 x 5 cm, weight: 5 kg more or less), with 4 tender rubber feet that help decoupling the unit from the "outside world". The ON/OFF switch is placed in the rear panel, close to the IEC mains socket. This means that it should be better to leave the DAC+, like any other D/A converter, permanently turned on.

It is also available a simplified version of the DAC+, simply called DAC, which comes without volume control and analog input. With the DAC you can save few hundreds dollars but you lose the preamp feature which is, in my opinion, very, very interesting as we'll see later.

I've tested and evaluated the DAC+ over a long period, using it as a standard DAC converter and also as a minimalist preamp.

Two hearts beat as one?

I've tested the DAC+ both with the old 20 bit DAC chip and with the new 24 bit. For those of you who are already familiar with the sound of the DAC+ I'd say that the new 24 bit chip is a huge improvement over the old chip: smoothness and clarity of the mid range improve and the air amongst instruments and singers increases. In a word it is much more "musical" and enjoyable.

Hence the following notes are related to the 24 bit version only. For more infos and upgrades please contact the manufacturer.

The DAC+ is a solid state component, like its brother the Black Cube, but, while the phono stage had a mix of transistor and tube sound features, the D/A converter does nothing to hide its proud solid-state soul.

The overall feeling is that of a taut, solid and punchy sound, like the one of a good solid state powerful amplifier. More precisely, few tube amps can rival the bass performance of a good solid state amp and so is the DAC+ bass range: extened till the first octave, very powerful, taut and articulated, don't be surprised to hear your loudspeakers going lower than ever :-) (see the review on Soundstage, for example). It is a nothing but excellent bass range, very close to the best bass performance of a good analog turntable, if you know what I mean.

Actually, in my opinion, apart from soundstaging and overall "musicality", one of the big pluses of the LPs was the bass performance and the dynamics. The DAC+ makes the CD sound close to vinyl, at least for these two parameters. Put a CD with a well recorded double bass or organ and your listening chair will tremble as well as your floor.The DAC+ possesses also a crystal clear mid range, with a good level of detail and introspection, not exactly warm but never aggressive. It is very analytic, it lets you discover each nuance of the recording and, of course, each error of the recording engineer ;-)

It is NOT the warm and rounded sound of certain D/A converters that try to mimic the sound of the vinyl discs: it is a sound made of a clean and open mid range, matched with a well extended and harmonically rich high range. For example, the harmonic richness of an acoustic guitar is preserved by the DAC+, you can clearly hear the fundamental note and then the harmonics expanding into your listening room. While with the old 20 bit chip the female voices were sometimes too edgy and plenty of sibilants, with the 24 bit everything seems far more natural and, quite surprisingly, this happens without losing any information in the high range. The voices appear much clearer and less artificial and grainy (digital?) though there's clearly much more detail and "air".

Used as a preamp the DAC+ retains its solid state behaviour, showing its limits only when compared with hi-end preamps that are, alas, much more expen$$$ive. Given the price of the DAC+ the performance, as a preamp, is pretty outstanding.

Dynamics

Solid state at its best here: the DAC+ is a NO FEAR HiFi component, it explodes (well, not literally :-) ) into your listening room and, as mentioned before, this performance puts its sound very close to the one of a good turntable. A friend of mine, in love with my Linn analog fron-end, when listening to the DAC+, has confessed that the CD CAN sound "dynamically" close to the analog source even without spending an arm and a leg on price-no-object D/A converters or transports.

The dynamic performance is probably one of the best qualities of this converter and it can rival with far more expensive units. Attacks are fast and decays are natural, with plenty of "breath" and echoes...listen for example the KO-DO Heartbeat Drummers of Japan (Sheffield Labs) playing the huge O-Daiko drum: you'll clearly hear the vibration of the drum after it has been violently hit by the player. A still open famous mathematical problem is: can one HEAR the shape of a drum? My answer is YES, if the converter is something dynamic like the DAC+!

When playing highly dynamic recordings, take care of the listening level...or your power amplier or your speakers may suffer ;-)

The DAC+ is good even when playing difficult instruments like the harpsichord, where a great amount of microdynamics is required: the harmonically rich texture of its sound is a thrilling test for any HiFi component. The German converter, thanks to its rich and detailed sound, succeeds in following each delicate and sudden variation of the instrument, giving you always a sparking musical reproduction.

3D imaging

As usual, the soundstage reproduced by a component that is precise and detailed like the DAC+ is nothing but excellently focused: to hear this you should bypass the volume control and use the DAC+ as a standard fixed-output converter. Indeed the DAC+ used as a preamp has a slightly narrower soundstage and it seems that the D/A converter section can play slightly better and more focused when the volume control is bridged.

This is obvious to me, as long as a far better preamp is used with the DAC+ working as a standard fixed output converter. But don't get me wrong: when used with its internal volume control it is quite impossible to detect the price range of this unit...you need thousands of dollars of a separated preamp to "tell" the difference. This leads to a pretty obvious question: the DAC+ is a converter matched to a minimalist preamp and it costs less than 2,000 dollars: how many DAC + separate preamp combos in the same price range offer the same sound quality? Very few is the answer, especially if you consider the price of a good interconnects cable which is necessary to link the DAC to the external preamp.

So, it is true, the DAC+, used as a standard DAC, has a better focused and wider soundstage than when the volume control is used...but the question is, how many preamps can reveal this? I've discovered this using the reference Thor Audio TA1000 preamp (7,000 $) and an Audio Research LS 15 preamp (soon on TNT-Audio) so...it's up to you (or to your wallet) to decide :-)

Some advice

As said before, it is better to leave the DAC+ permanently turned on, it is a trick suggested both by the recessed position of the ON/OFF switch and by a non-written law on D/A converters (leave them on, they'll sound better).

The DAC+, thanks to its tender rubber feet, sounds good independently of the surface, provided it is sufficently stable and solid. This is a sign of the good mechanical qualities of the layout and of the cabinet.

Finally, a few words about the mains cable: thanks God it is detachable so you can use any special audiophile AC cord (for example, our DIY project Merlino). The DAC+ designer, Norbert Lehmann, seems very interested in equipping its products with better AC cords and I hope ANY HiFi designer in the World will start thinking at the mains cable like a COMPONENT of the unit itself which does affect the overall performance.

Complaints

Considering that the DVD Audio seems here to stay, I'd like to see the DAC+ capable to convert the new 24/96 digital format. I believe the designer is already thinking about this possibility.
Secondly, a minor complaint: the 4 different digital inputs can be selected by 4 microswitches in the fron panel, each one equipped with a red led light. Now, the problem is that it is very DIFFICULT to remember which numeber refers to the desired input so one has to look at the rear panel, and switch the right button in the front panel. Things are even worse since there are two coaxial inputs...it could be way easier if the 4 switches, instead of being labelled with 1, 2 , 3 and 4, would have been marked with Optical, Coax 1 and 2, XLR.

As for the sound quality: apart from the differences remarked above related to the 3D imaging there's little to say about an HiFi component that at a price of a DAC converter offers you a hi-quality preamp....included!

Conclusions

Less than 2,000 $ for a 24 bit DAC converter featuring 4 digital inputs and 3 digital outputs (even XLR balanced!) plus an analog aux input, hi-quality components (Noble, MKS, Analog Devices, Crystal), a toroidal transformer and a huge power supply section...it sounds like a bargain to me. Then add the possibility to customize the unit to suit your needs and to use it as the minimalist heart of your HiFi system: 4 different digital sources (CD, DAT,...) plus an analog one (turntable via a phono preamp)...it sounds like a better bargain to me. Then hook up the cables and listen to it: its sound, especially for dynamics and quality of the bass range, can outperform even more expensive DACs...if it is not a bargain, how would you call it?

Norbert Lehmann proves one more time that you don't need to spend outrageously amounts of hard earned cash to enter the hi-end world. Of course, you need to save on cool looks, gold plated knobs and massive CNC aluminium face plates...but, after all, it's the MUSIC, stupid! (right, Steve?) :-)
The Lehmann Audio DAC+: when Music really matters...

As usual, a huge thank you to Norbert Lehmann who has sent us the unit for this listening test and for having listened to my humble opinion about the 24 bit new DAC chip.