Who attaches tidy headphone to mobile audio devices, like portable MP3 and D-CPlayer, or also to sound cards, enough a herbe disappointment often experiences: Usually it sounds only quietly - and often also still badly. Here the likewise mobile Porta Corda of Meier audio remedy is to create - and tut's also.
Motive number 1 for the link high-quality headphone at mobiles audio equipment is the quality of the provided ear plugs lausige in all rule. In addition, at sound cards some speaks for good headphones: In the price efficiency comparison they cut off far better than each PC loudspeaker system, which came us so far into the fingers. And one saves the trouble of the wiring with usually off been situated stereo-Anlage.
The disappointment follows nevertheless usually on the foot, because it usually schallt thinly and more or less strongly distorted from the caps. A cause for it are almost always to weak drivers, which come with usually higher impedance (apparent impedance) and the smaller efficiency of better headphones not by right.
Mobile audio devices about carry 5 out to 10 in the majority only twice mW at 16 or 32 ohms. That preserves battery or Akku (as well as the nerves of the standing around), but under 20 mW per channel plays hardly tidy headphones decently up. Ergo arises the desire for an acoustic after Burner, which lets anbrennen in puncto sound quality nothing and after possibility be also still mobile should. Evenly that is to carry the portable headphone amplifier Porta out Corda of Meier audio.
The fact that as a small piece of audio technique is to cost as the Porta Corda stately 175 euro is because of the high-quality interior life. And one put, puts it only into operation the required sound quality doubting questions about the price performance fast ad acta.
The native dutchman January Meier is not only a studied nuclear physicist, he has also a doctor title as an engineer of the biomedicine - and a passion: Music and their playback. Together it led to the fact that he operates a headphone selling in the Internet apart from his main profession now also and manufactures in the Frankish exile own headphone amplifiers.
Who can do without the mobile operation, should therefore also quite a view of the stationary Corda Headamp-1 - or briefly: HA-1 - throw. That costs with 360 euro also scarcely doubly as much as its portable brother, sounds however even still better - among other things, because no consideration to the requirements must be given here in mobile operation.
Interior life and scope of supply
But back to the Porta Corda: Somewhat the Design homemade at first sight should not emislead about the wertigen Innereien. Among other things there four individual operation amplifiers of the type LM6171, a switching potentiometer of Alps, metallic film resistances, plastic condensers, Puffer/Sieb Elkos with altogether 3000 µF capacity as well as a quality circuit board with 70 are µm to thick copper coating. The switches and sockets offer gold and silver contacts.
In addition gibt's additionally a short cable connection with 3,5-mm-Stereo-Klinken at both ends and one likewise of Oehlbach manufactured 120-Ohm-Adapter. Over the latters the output impedance of 0 ohms can be raised for better coupling to certain headphones to the default value usual with integrated amplifiers.
Current supply
For lot putting one needs only a 9-Volt-Blockbatterie - or a linear regulated power pack with 6 to 28 V together with 9-V-Adapter-Clip, because a separate socket for the external current supply is missing. With the 9-V-Block the Porta Corda is to hold out approximately 48 hours.
That seems convincing, because we heard meanwhile already well 30 DS with an alkali battery of Duracell and to register only now a gradual leaving of the thrust within the bass area. Likewise suited, more pollution free, but not so long-lived 8,4-V-Block-Akkus is - preferably in NiMH execution (nickel metal hydride), because nickel cadmium Akkus in the same format has fewer capacity and to hold thus fewer for a long time through.
Who operates the Porta Corda mainly at home, should not however only invest for environmental protection reasons into a power pack: Because the more one the max. voltage of 28 V approaches, the more near arrives one also at the max. amplification factor of 17 dB. That creates certain volume reserves, even if one once again on CD also quite low accommodation level pushes - which occurs in particular with older AAD accommodations (similar accommodation and merging, only digitally stored) quite more frequently. Besides a current supply with more Schmalz offers also to more dynamics and increases the sound.
In order to plumb, we let the klanglichen abilities begin the Porta Corda against the Marantz PM510 - a somewhat older full amplifier in the usual 43-Zentimeter-Format also quite prop. rem headphone exit -.
As source mainly the proven portable CD Player Sl-ct570a von Panasonic served. As transducer above all - by the way quite favorable - the DT 531 was used from Beyerdynamics HiFi headphone series; in addition still the DT 990 pro (250-Ohm-Variante) from the professional series of Beyerdynamic, the K 501 of AKG and the SR80 von Grado. All this headphones suffer with direct connection to the Sl-ct570a under the initially specified problems.
Convincing sound
The results speak for the Porta Corda: It is able not completely to deklassierien the PM510 - in addition principle conditionally still somewhat more thrust in the lowest bass cellar is missing to it. In things speed and dissolution of high clay/tone must the integrated Marantz amplifier however that something over cigarette-box-large and without Battrie scarcely 100 gram easy Porta Corda struck give itself.
Beyond that the portable headphone amplifier of Meier audio harmoniert also better with the low impedance Grado SR80, which at the Marantz a badly bright and rather importunate Timbre assumes. One obtains the best results by the way usually when direct connecting the Porta Corda to the LINE exit of the source of sound. By its favorably selected feed impedance of 3 kOhm it accumulates in addition, at headphone exits to good form.
In the end still a few words to a so far unmentioned special feature of the Porta Corda, the insertable CROSS feed filter: Who hears normally only with loudspeakers, which may appear rather unnatural for lack of space reflections clearly higher the kanal-Trennung headphone. Exactly the Porta Corda copies and deals these missing reflections with active CROSS feed filter by a purely similar circuit with it a possible hearing stress factor.
Total total: very well
Price achievement: good - very well *
*) subjective valuation - in practice dependent on the respective sound gain
That's a rather pathetic Babelfish translation for ya. I think we should just wait for lini's translation...
