MC loading at 47K


Hi All,

Just after some expert advice from your good selves if I may. My current system is as follows:

Musical Fidelity KW550 intergrated amp which has a MM and MC section, both loaded at 47K. The only difference between them is the step up voltage.

My turntable is the Rega P9 with Ortofon Kontrapunkt A.

Looking at changing my cartridge but honestly cant decide between MM or MC.

My music taste are as follows:

Reggae
Soul
Female Vocal
RNB

No classical or jazz.

So what should I choose based I'm only limited to a 47K loading. I was thinking either of the below:

1. Ortofon Jubilee (MC)
2. Ortofon 2M black (MM)
3. Clear Audio Maestro (MM)

Is there a down side to loading up a MC so much?

Thoughts please...thanks
che13
Something that hasn't been mentioned: Anyone with a phonostage offering instantaneous load change comparisons like my Aesthetix Rhea will be aware that the audible difference as you go from sub-100 ohms to 47 kOhms isn't nearly as great as you might expect. Yeah, there's a difference (especially going from sub-100 immediately to 47k) but the incremental changes are pretty subtle.
Audiofeil:I have done and you are NOT the last word on this subject even though you are trying to be by your soapbox statements....

Dopogue: I agree with you on that. I am using the Phonomena and the changes require extended listening to a wide variety of material. Other items that have a more obvious impact to sound are whether the arm is level or slightly lower at the back and/or the playing weight. These should be optimised BEFORE the load resistance into which the cartridge is fed is evaluated.
It's simple electrical theory and physics young man.

You need to read more and post less.
This has been covered in other threads.

However, in a nutshell there is a simple reason that you see variable results. It has to do with how sensitive the phono section is to Radio Frequency Interference (RFI).

Now its a fact that at almost any loading value you can put on a LOMC, you will not affect the response of the unit at audio frequencies. But when you install the loading resistor (often quite low in the case of LOMC) you can hear a change.

This is because the cartridge has an inductance, the the interconnect cable has a capacitance. Together they form a tuned circuit at ultrasonic (RF) frequencies. The action of the the cartridge playing provides the energy- and so the tuned circuit thus injects RFI directly into the phono input.

Now if the phono section is stable with the presence of RFI at its input, you will not hear a lot of effect with loading the cartridge. But if RFI is able to mess with your phono section, then you will hear big differences. The effect of a resistance is that it lowers the energy of the tuned circuit. When that energy is low enough, the perception will be that you found the sweet spot.

Mind you, this is the 'nutshell' version of this explanation. But it does explain why you will see difference of opinion here.

The bottom line: if you hear big differences with loading, your phono section is sensitive to RFI.