The 'tube-transistor' enigma by MC carts?

By accident I got to know an guy from Swizerland who has
worked for years as technician (R&D,testing,manuf.etc) by
Benz. I made some joke about 'Zelle',the expresion he used
to refer to carts,by asking if the carts are made by
prisoners? ('zelle' is 'the box' in the prison) He appreciated my joke and explaned to me in 2 sentences
something I never thought about. There are 2 kinds of
'bobins': iron and the other kind. The 'classical example'
of 'iron' is the Ortofon SPU. The advantage: stronger signal and some kind of 'pleasing warm sound.the disadvantage:(more)distortion.
The 'ruby-cross' bobin has (much?) less distortion but can
sound 'thin' depending on the rest of 'the chain'.
This is obviously the so-called 'Holistic' approach ;
aka Rauls 'it depends...'. Me? Because I can't cope with
more then 2 variables at the same time I am for 'simplicity' approch. The best 'definition' of this
approch is from O.Wilde:'I have the simplest tastes. I am
alwys satisfid with the best'. So I am still seaching.
Raul will you please bring (more) light to this issue?

The trade off with an air core versus an iron core or other variant is that you need more turns of wire to achieve the same energy out. So this adds resistance.
Dear @bimasta: Always exist trade-offs. I'm not  cartridge designer but maybe the best is to build cartridge coreless and yoke-less like the Yamaha X-1s. I own it and is truly good performer even that's a vintage one.

@chakster — Thanks, I think I have that text in the booklet that came with it. But a question...
" Air core coil is adopted as coil.... In addition, by adopting a new special lightweight resin coil bobbin...
It seems "core" and "bobbin" are different things. I thought both referred refer to whatever the wire is wound around, i.e. a single thing — apparently not. So now I don’t know what an "air" core is. Can someone educate me, and explain the difference between core, bobbin, armature?

@lewm — More resistance would lower the output, yes? But we’re dealing with low output anyway. Would it have any other significant effects?

I was stunned to see that this was/is my own thread. From 2009!

I also had difficulty to recognize my own English.

Well the expression ''CORE-LESS''  may give the right direction

for our thoughts. ''Iron-core'' in the ''coil-former'' is used , like

by cheap inductors , to increase the cart output. As Lew put

it ''less coil wire'' is then needed reducing the moving mass.

Lukatatschek, the owner&designer by Benz , stated ''I don't like

iron'' anywhere in the signal  path and use ruby plate to wind

coils on. But his LP S (or mr.) has + 40 Ohms impedance

''suggesting'' much (more) wire. Mori san invented ''8 form

 coil-former'' for his series XL Sony MC's. Those coils are also

''core-less'' but the whole series, like Benz, has +40 Ohms

impedance ''implicating''  more wire. Ergo: those LOMC''s with

output around 0,2 mV or less are ''core-less'' with little wire

and with low impedance.

@bimasta  it's nice to run into somebody with an FRMC201.  I have had one for a while when I picked it up on a curiosity. I absolutely love it, it is fantastic Mounted on an ET2.   It is an air core  design with I believe .17 mV output.