Question about Cartridge Loading

Raul, It’s not my rule. It’s just physics. If you load a cartridge that has a 45R internal impedance with a 100R resistor, of course it will work. But a large fraction of the cartridge voltage output will be lost to ground and you will lose some HF bandwidth. These two numbers can be precisely calculated but the end result is more complex because of frequency dependency. If the net result sounds best, I am not about to quibble, but if a novice asks me a question about loading, I feel obliged to tell it like it is. Then let the other guy decide for himself.

As to the importance of inductance in the Hegerman calculator for LOMC cartridges.  Did you add in say 10-20 microHenries for an LOMC, or whatever is the value for any particular LOMC?  And does it make a difference?  Of course it will perturb the value a bit, but not by any important amount.  Tell me what you found out.

Jay, I always use the cartridge manufacturer's suggestion and stick with it but, my phono stage requires removing the bottom and soldering in resistors to change the load. Just use what you think sounds best to you. It is your system and your ears. 

With experience you will know what you want to hear. When you are not sure you tend to second guess yourself. As an audiophile you owe it to yourself to listen to as many systems as you can at dealers and shows to get an idea of what systems can do. You'll have to dweedle through a bunch of bad systems but when you hear a good one you will know it for sure. If you want to get first rate service at a high end store just drive up in a 911. A Yellow one works best:-)

Coil inductance has biggest impact for cartridge loading if its inductance is higher than 1mH.

If you want to use a LOMC cartridge, avoid phono stage that only provide 100Ω fixed loading resistance for MC cartridge.

If you have a LOMC cartridge, you'll find that loading has little effect on its audible bandwidth. However it can have an enourmous effect on the phono section being driven by the cartridge, if the phono section is sensitive to RFI being injected at its input.

Above @hagtech kindly posted a link to his calculator. If you drop the inductance value of your cartridge into it, and then the capacitance of your phono cable in too (a typical phono cable is about 20pf/foot, FWIW), the calculator will show you the resonant frequency. With LOMC cartridges this is often in the MHz region- definitely Radio Frequencies.

That peak can be set into what is called 'excitation' in radio parlance, caused by the operation of the cartridge. This results in RFI injected into the input of the preamp, and many preamps don't deal with that very well (for example they might sound bright; you might also get more ticks and pops if the preamp has a poor high frequency overload margin). The loading resistor serves to detune that resonance, thus eliminating the RFI.

If your preamp can deal with the RFI then you'll find the loading resistor has little or no effect.

@lewm  : " cartridge was reviewed and the reviewer said performs just fine at 100 ohms that's is way out of your 10X rule. "

" lose some HF bandwidth.."  how much.Example?

Normally SPL goes a little lower.

R.