Added an SUT...not sure I understood this

@intactaudio 

Obviously you haven't got a clue so I'll explain it to you - actually here's a quote from JCarr

The loading resistor value is placed across the phono cartridge's output terminals, which means that any output voltage produced by the cartridge will be forced to flow through the load resistor in the form of current. The higher the load resistor value is, and the farther the net impedance is from the cartridge's internal resistance, the less current will be produced. Conversely, the lower the load resistor value is, and the closer the net impedance is to the cartridge's internal resistance, the more current will be produced.

IMHO, the only time that forcing the cartridge to produce more output current could be justified is when using it into an IV phono stage. Since this kind of phono stage converts input current into output voltage (and is more or less oblivious to input signal voltage per se), it would make sense to feed an IV phono stage with as much input current as possible. An IV phono stage, however, possesses de facto a low impedance input node that receives the output current from the cartridge as a series element (without needing a separate load resistor). This is not how a normal loading resistor works with a typical voltage amplification stage, since there the separate load resistor bleeds the current from the cartridge into ground (thereby wasting that energy). Also, IV phono stages sound qualitatively different to voltage amplification phono stages., and part the reason is that undoubtedly the cartridge is forced to operate into a zero-ohm load (or some other values that is quite close to the cartridge's internal resistance).

In other words comparing the resistive load in a current mode mc input to the the resistive load in a voltage gain mc input is like comparing apples and oranges.

If you cant understand what JCarr wrote, and don't understand the difference between voltage and current then I cant help you any further.

JCarr makes the exact point I am ultimately trying to get to when he says the below.

 Also, IV phono stages sound qualitatively different to voltage amplification phono stages., and part the reason is that undoubtedly the cartridge is forced to operate into a zero-ohm load (or some other values that is quite close to the cartridge's internal resistance).

I don't necessarily agree with his use of the term "forced" but that is for another day.  He attributes  "part of the reason" for the difference  in sound to the load the cartridge sees and I fully agree with that thought. Since this branch of the  topic is about the load the cartridge sees and not how that load is obtained, discussing the difference between current and voltage amps is not at issue.  It just so happens that a current amp gives an extreme example of "non-traditional" loading.

 A cartridge is a two terminal device that sees a two terminal load downstream.  It doesn't know or care what form of amplification that load takes, it just does what the load tells it to do.  

dave

Yes, JCarr sort of contradicts himself a bit and ends up being half right.  The reason a cartridge sounds different under a heavy load is because the low load impedance suppresses output voltage. But a preamp that is uninterested in output voltage would not be affected by this phenomenon.  In the case of the IV preamp, the low input impedance (not quite the same as load impedance) results in high current flow through the preamp.  It does for the IV preamp what a high load & input impedance does for a traditional preamp--maximizes the electrical signal that the preamp is using.

Changes in sonic character between the two approaches may be based on inherent differences in the architectures, or based on differences between the way the cartridge's--let's call it "frequency response"--as expressed by its current output varies from its "frequency response" as expressed by its voltage output, but those changes cannot be attributable to the effect of loading on voltage output since the IV preamp effectively ignores that effect.

@woofhaven1992 

 The reason a cartridge sounds different under a heavy load is because the low load impedance suppresses output voltage.

so add more gain.  I'm not trying to be cheeky here but this becomes a problem related to what happens downstream of the cartridge and not with the load the cartridge sees.  If you load a cartridge severely and do not have a capable low noise good sounding stage after it things will indeed go south.... this is not a problem with the cartridge load per se but with the behavior of what follows.  

In the case of the IV preamp, the low input impedance (not quite the same as load impedance)

how can the two be separated form each other?  from the cartridge POV, how can 3Ω be different than 3Ω?  I am speaking primarily about the effects of the load on the electromechanical behavior of the cartridge and what impact that may have on the sound.

 but those changes cannot be attributable to the effect of loading on voltage output since the IV preamp effectively ignores that effect.

Sure the IV preamp can ignore that its low input Z effectively reduces the output voltage to 0.  My question is how can the cartridge ignore that it is seeing a load that is possible a fraction of its internal impedance?

Lets get back to the simple question I asked....  If going well below a cartridge manufacturers load is not recommended, how can we reconcile the use of transimpedance amplification or in your case a load that is 1.7X the cartridge internal impedance?

It is my belief that when specified by the cartridge manufacturer the load value range would relate to the behavior of their cartridge and not in response to the unknown capabilities of what follows.  In any case... Like you I feel that number is only a suggestion and people should feel free to use whatever load sounds best to them.

dave

This is a second take on woofhaven’s post, nothing to do with what Intactaudio posted above, or only tangentially. Woof, you seem to ignore the fact that none of the available current driven phono stages actually presents a "perfect" zero impedance load to the cartridge. Each of the different units has a finite input impedance that is above zero and usually less than 10 ohms. Case in point is my BMC MCCI that I bought recently to experiment with current drive in my home system. (Otherwise, I would have to depend upon others’ opinions, which I don’t find helpful to do.) The MCCI has an input Z stated by the maker to be <3 ohms. I guess that’s why Intactaudio uses that value in his thinking process. In other words, none of these devices is "perfect" when it comes to current drive, because they really cannot be perfect; zero ohms is a short circuit to ground. My experience with two or three very good LOMC cartridges driving the MCCI is that you cannot predict in advance what you’re going to get out of the phono stage in terms of either gain or tonal balance. I’ve had to think of the cartridge and the MCCI as a single device where a major determinant of the output SQ and db is taking place at the interface between the cartridge and the MCCI I/V stage. The cartridge internal impedance, its voltage output (because that affects current output), and probably its inductance along with the ~3ohm input Z and the current amplifying devices of the MCCi would seem to be the important variables. So, there’s no free lunch, and there is nothing inherently superior about current drive vs voltage drive, at least so far in my experience. This is not to say that the results cannot be superb.