Cartridge Loading- Low output M/C

@krelldog
If the cartridge needs loading below 47K its an indication that the preamp is not stable with Radio Frequency Interference (RFI) at its input.

The loading resistor is not for the cartridge, its for the preamp.

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!
The loading resistor detunes the RF circuit, preventing the RFI. The problem is that in so doing, the cartridge is asked to perform more work as it has to drive the lower resistance. This makes the cartridge cantilever stiffer and less able to track higher frequencies. This is why the resistor can act as a tone control.

A side problem is that preamps that have problems with RFI are also far more likely to produce ticks and pops. This is often due to poor overload margin, since a signal that is 1000x more powerful can overload the preamp. The other reason is that the phono circuit can be unstable and react poorly to RFI; either way if the phono section does not have these problems, a side benefit is far less ticks and pops- you may not ever hear any on an entire LP side.
Many phono preamp designers don't realize the RFI implications and so don't know to make sure their circuit is immune to these problems. So instead you see loading switches and the like...

On that thought...all I can say is that my phono preamp (Plinius Koru) is very highly reviewed. I'm currently using an Ortofon Quintet Black. My settings are 22 ohms and I'm using 66 dbs of gain. The sound is spectacular...no issues. These are the only settings I've used since purchasing the Koru. Thus my apprehension with where to set the Koru with my soon arriving Cadenza Bronze...BTW it will be attached to my new VPI Prime Signature. I'm sure I can find the right settings...just really looking for a starting point.

The best starting point to check your cartridge and phono stage is 47k Ohm for MC (take in count what Atmasphere said)  

@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).