Similarity between ribbon microphones and moving iron phono cartridges

I wrongly new or assumed that all cartridges that look like MM are mocing magnet.


Few days ago  Stanton 680 look alike cartridge (with missing moder sticker) had been setup on a Technics SL1200MK2 and the sound was impressive and easy, deep and detailed. Very extended high frequency response.
Some sibilant problems but not sure yet whether this sibilant information is already in the record!


Reading patents
US2538164 by Norman C. Pickering
US3546399 by Walter C. Stanton, Laurel Hollow


reveal that the diamond moves a thin metal which then completes (varies) the magnetic circuit inside the cartridges created by a non moving (stationary) magnet. Coils in the magnetic circuit sense the change in magnetic flux and by Faraday's law an EMF or voltage (the music voltage signal) is created.


This looks very nice as a relatively heavy magnet does not have to move. Only a lightweight cantilever peace of iron moves. Magnetically saturated.


It is a bit like ribbon microphone with the difference that the voltage is not taken from the iron itself but by the coil.
So it reminds a bit moving (but not moving actually) coil microphone.
It also of course reminds electric guitar pickups, the steel vibrating wire being the cause of variable magnetic conductance of flux through the coil.


Many turns of wire create the normal say 1000Ω output which needs to be terminated by 47KΩ and capacitance.
Few turns of wire create a say 100Ω or less output impedance to be connected to an MC input, input transformer, Pleiades V6 front end etc.


A lightweight iron cantilever has small mass ie accelerates easily, and less tracking force is needed. For example the Stanton non DJ aftermarket stylus inserted on the unknown Stanton (680?) cartridge starts tracking at 1.4g.


A smooth sound.


At the moment treble is too extended. But vertical tracking angle has not been looked at yet.


Today searching on Google:
https://www.vinylengine.com/turntable_forum/viewtopic.php?t=26815


"Post by bauzace50 » 01 Apr 2010 16:24 true enough! Curiosity killed the cat, and that's behind the premise of this thread. Is the Moving Iron principle more beneficial, in and of itself? Why not MM? Why not MC? The all-MI-Grado contingent seems aligned WITH MI (at least, BY DEFAULT, if not by militance!). Other MI owners have not really manifested themselves about this. Think about owners of Stanton 681 series, Decca, ADC XLM (et al.), Sonus, General Electric Variable Reluctance, (some of Garrott Bros.???), Acutex, Bang & Olufsen, Ortofon Super OM, Ortofon VMS, SoundSmith and...any others? The difference cannot be caused by low inductance-and-resistance,
because only the Grados qualify (with the exception of a few MM-LoZ Pickerings and Stantons). The true operational cause HAS to be the MI principle...I think."



So are MI carts giving MC cartridges a run?


See also:


Feynman Lectures on Physics - Feynman, Leighton, Sands