Cartridge Loading- Low output M/C

@atmasphere 

I didn't know most of that. Thanks for sharing!

Krellog,

You got a lot of useful information and advice above, particularly from lewn and atmasphere.  From my own experience, I tend to like to run my cartridges wide open, because my tube-based phonostage is not prone to overload from RFI and I get the most top end extension and "air" that way (this open top end is why one pays big bucks for MC cartridges).  But, if there is close to universal loading (one that works reasonably well with most MC cartridges) it would be around 100-150 ohms. 

Have you listened to your setup with a different loading than 22 ohms?  That would be a LOT of loading for almost any cartridge and it would tend to kill dynamics and make the top end dull.  While the particular sound one likes is a personal preference, I would be concerned that you might be utilizing excessive loading to compensate for other problems that are better addressed more directly.  For example, if you have the tonearm raised too high at the pivot (excessively high VTA/SRA), this tends to create a thin, edgy sound that you might be compensating for by excessive loading).

Dear  @atmasphere : The OP is asking for loading and not why many phono stages works in different way when we make load values.

Who cares, he as any one of us already owns a phono stage it does not matter what and no one can make a world research to find out which phono stages works as should be, it's imposible to do that.

So, what each one of us have to do is to load our cartridges according what we have and according each one music/sound priorities. That's all.

R.

Dear @krelldog : For the first 50-60 hours test it with 100 ohms . During that time is only for the cartridge can overall settle down, after those 50-60 hours you have to re-check the tonearm/cartridge whole set up: overhang, cantilever alignment, VTA/SRA, VTF and AZ and after this " fine tunning " excersice you can to start your listening tests starting with that 100 ohms and  listening for a while and the make a change either to 47 ohms or 220 ohms then you can decide where is better for you.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Atmasphere 5-21-2018
This is because the cartridge inductance combined with the tone arm cable capacitance forms a tuned RF circuit- which is energized by the cartridge signal.  It can be over 30 db higher than the phono signal- thats about 1000x more powerful!

To add to Ralph’s (Atmasphere’s) response, with which I of course agree, the input capacitance of the phono stage will add to the capacitance of the phono cable.  And I see that the Koru provides two selections for input capacitance, namely 100 pf and 570 pf. You are likely to find that the 100 pf setting will allow you to use lighter loading (i.e., higher resistance values) than the 570 pf setting.

Also, related to all of this the following excerpt from a post dated 8-14-2010 in this thread, by Lyra cartridge designer Jonathan Carr, will be of interest:

I should now debunk another myth regarding loading, which is that low-impedance MC cartridges are insensitive to capacitive loading. OK, the MC cartridges themselves aren’t particularly sensitive to capacitance, but the inductance of the cartridge coils will resonate with the distributed capacitance of the coils and the capacitance of the tonearm cable to create a high-frequency spike, and this spike certainly is sensitive to capacitance. In general, the less the capacitance the better. Having more capacitance (across the plus and minus cartridge outputs) will increase the magnitude of the high-frequency spike and lower its frequency, neither of which is good news for phono stage stability or phase response.

Generally speaking, the greater the capacitance across the plus and minus cartridge outputs, the heavier the resistive loading needs to be to control the resulting high-frequency spike. Conversely, less capacitance allows the resistive load on the cartridge to be reduced, which will benefit dynamic range, resolution and transient impact.

Good luck.  Regards,
-- Al