The correct internal-inductance of Windfeld cart.?


What (on earth) is the correct internal-inductance of the Ortofon Peer Windfeld cartridge?

They made a mistake in the brochure about the loading impedance: it says >10k but should read >10 ohms. This was admitted by the factory's techies.

The brochure also says internal-inductance: 700 mH !!!
This you would expect from an MM cart. Was this also a factor 1 000 error? I can not find ANY help on the web to clear this up. Can any one help?
axelwahl
Axelwahl, You originally asked about inductance, not impedance. This naturally led some people to ask why you wanted that information, since the proper loading of your cartridge is easiest to calculate based on the square of its turns ratio of the SUT you are using, if you know the desired load. For example, if you want the cartridge to "see" a 100-ohm load (a reasonable guess for a cartidge with a 4-ohm internal impedance, altho I know the Ortofon likes to see a higher value), and if your SUT has a turns ratio of 10:1, then the proper value of the load resistor on the secondary side of the SUT is 10,000 ohms. (The square of the turns ratio = 10^2 = 100; 100*100 ohms (the desired load) = 10,000 ohms.) If you want the Ortofon to see 500 ohms, then you need a 50K ohm load resistor. Maybe you know all this, but the fact remains that inductance of the cartridge is not needed to make this calculation. Folks were trying to help you.
Thanks for the help, why I asked for the correct impedance?
To determine the bandwidth of my system after SUT loading!
f/3dB = R / 2pi*L ...that's why :-)

Got it right now by primary loading 13ohm! Fidelity Research XF-1 type M (1:31.6 ratio) ergo 47ohm natural impedance with 47k phono-pre input impedance. (47k/31.6^2 = 47ohm)

So, 13*47/(13+47) = 10.18 ohm primary input impedance to match PW >10ohm recommended impedance.

The brochure I was referring to is the very one THAT CAME WITH THE CART! Mr. Rauliruegas
(Ortofon do know about their miss-prints, why ask?)

Meanwhile NOBODY at Ortofon commits to a correct impedance figure, other then 10 - 100uH -- Not so professional I say --- the reason? "We don't measure it..." well, well, well
According to the Ortofon specification sheet, the PW has an internal resistance of 4 ohms, and an output of .3mV. If you are trying to work out what kind of step up transformer will work for this cartridge, those numbers are what you need. These are pretty much normal numbers for a relatively low output cartridge.

As for the inductance, I have no idea. Why would you need to know the inductance? I would assume that the PW is like any other MC cartridge, which means an insensitivity to capacitance loading.
Dear Axelwahl: I don't know to what brochure you are reffering but here you can read that >10 ohms:
http://www.ortofon.com/index.php?option=com_content&view=article&id=230&Itemid=225

I don't know too why is so important to you the internal-inductance but you can ask directly to Ortofon here:
http://www.ortofon.com/index.php

Regards and enjoy the music.
Raul.
That sounds so impossibly high that I agree it MUST be an error. There's just not enough wire in there to generate that much inductance. I will bet that they meant to write "micro-" Henries, not "milli-". Even that much seems a tad high. Of course, I am only guessing.