Sennheiser MD441 U3 and Pleiades V6

At the moment they do not mate well.


(See later post on how the problem was accidentally solved):
http://euroelectron.blogspot.com/2018/06/the-sennheiser-md441-u3-to-pleiades-rl.html


The Pleiades V6 with the 1:10, 140mH and 10:1 800mH input, output transformers make this world class mic sound a bit honky tong. There is an almost nasty exaggeration on mid range.


Signal path, setput:


Male singing voice at 4in to 8in - MD441 U3 - Pleiades V6 - Sony TC-D5 Pro - HD580


Next the MD441 U3 was directly connected to Sony.


The sound was almost unusable because of extreme proximity effect. Perhaps a quite large distance the sound could natural but the acoustics of the living room do not allow this. The gain on the Sony had to be increased but it was mostly that bass content was heard due to the proximity effect.


Next the MD441 U3 was connected to the small ratio BBC transformer and then the Sony TC-D5 Pro.


The sound was amazing. One of the smoothest sounds heard on the Pleiades experiments. There was nice proximity compensation. Mid and treble was as sweet and smooth.


There was some increase in impedance and voltage which suited very well the MD441 U3 and the Sony TC-D5.


There was some electromagnetic hum pickup up noise as the BBC transformers were just in an aluminum box and it is not certain that they were made for low level microphone work. Their inductance and sound made the MD441 sound like the diamond it is.


Signal Path, setup:


Male singing voice at typically 5in - BBC LL/210A transformer 115mH:382mH - Sony TC-D5 Pro - HD580


The gain on the Sony had to be set to fairly high and fortunately there is a 1:1.8 stepup from the transformer. But the sound was amazing.


More experiments are needed including winding a 1:1.8 transformer which stated inductances on a supermalloy ring core by Magmet or Arnold or a mumetal tape wound core or a Nanoperm nanocrystalinne tape wound core by Magnetec.


It is certainly good news that a world class sound can be obtained by just adding a signal transformer with the fabulous MD441 U3 and Sony TC-D5 Pro.


If the signal to noise ratio proves to be high without the V6 booster preamp an even more portable signal path is possible. Boosting and proximity compensation is made by just a transformer between mic and preamp. And a signal transformer is a passive device, therefore no extra battery (or power consumption) is needed.


(Later addition): see also AKG D1000 and Pleiades V6 post. Is the cause of lesser sound the input transformer of V6 being overloaded by the big bass due to the proximity effect?