Wednesday, March 21, 2018

The Grampian DP4/L still sends for tea the rest mics


More world class moving coil mics where tested and the DP4/L sends them to the cleaners. Well,the above comments may be exaggerations but in all those subjective brain perception tests this is how it is felt.


At the moment it is the Pleiades reference mic.


Grampian say in the mic operating instructions that it is the mic against which all others are judged. This is a very bold statement. They knew.


Perhaps the Pleiades 1:10, 140mH input transformer used in the Pleiades V6 booster and the DP4/L match like hand and glove...


But still it is the best sound of all the previous experiments with the mics and different tranformere mentioned.


Signal path, Setup:


Singer's brain - Male voice singing A Taste of Honey - mic at 1in to 6in - Pleiades V6 - Sony TC-D5 Pro - Sennheiser HD580 - Listener's brain


On voice not loud, not too soft...


Compared to the DP4/L...


The Schaub Lorentz MD200 sounds too bright but great (understandable since it is of 750Ω impedance)


The Electro-Voice RE-15 sounds amazing and great but there is something even more natural on the DP4/L


The Electro-Voice RE-16 same as the RE-15 but more bright and you can go closer than the RE-15 for same bass.


The Electro-Voice 635a amazing but still the DP4/L more natural on detail and less bright. As if the DP4/L does not have the rising HF response. Could it be that the DP4 has compensation for the presure doubling effect, ie is flat at 0 degrees incidence therefore deliberately non flat for random field?


The Sennheiser MD21 HN amazing and natural and perhaps smoothest but perhaps bright.


The MD211 great and full but with less natural and less bass. (The MD211 should be connected to a transformer primary winding input inductance of typically 300mH. Also a proper cable needs to be made for it. The SM200 and MD211 were connected with untwisted alligator cable clips to the connector after the mic). It was also bright and of course possible RF pickup did not help.


The Shure Unidyne III, vintage SM57 great but still the DP4 more full and natural and easy while being lively too. Is there something important in metal diaphragms?, is the DP4 diaphragm made of aluminum?


A mic that sounded great to the above setup is the Sennheiser MD112 although not directly compared to the DP4/L yet.


The DP4/L has an amazingly low handling noise. Low hiss. No buzz. The most likely reason is that there is no transformer inside. So one has direct access to the amazing 25Ω voicecoil.


Pleiades V6 schematic

Compared to the other mics the DP4 needed more gain increase on the Sony since it is 25Ω but who cares. The gain adjusting potentiometer on the Sony has to be at 4 instead of 3 out of 10 for example. Connected as all the other mics to the Pleiadws V6 booster it was possibly the mic with the best signal to noise ratio.






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