Cartridge Loading- Low output M/C

I may not be a renowned Audio Designer, but I am a somewhat renowned IC designer with credits that include cell phone transceivers and high performance opamps. 
In truth, the issue with phono stage RF has little to do with the capacitance loading- rather it's that many RIAA stages are designed to be non-inverting and lack the additional pole necessary to provide attenuation at ultrasonic frequencies and above. For example:
http://audiokarma.org/forums/index.php?threads/ad797-phono-stage-build-and-help-desk-thread.501186/p...
Where I discuss this very problem as an aside to optimizing an opamp based phono stage.
The non-inverting amplifiers used in an RIAA stage never have a gain below unity unless an additional pole is added. It's hard to see why adding a capacitance of significant value to the input of a phono stage helps when the self resonant frequency of most larger value caps is well below the RF region of interest. Indeed, if that is your concern, then adding several caps of scaled value 1-2 orders of magnitude apart, say 0.1uF//3300pF//100pF as the cartridge load would be the way to go, and who does that- except as an extra pole in a non-inverting RIAA stage.
I'm a believer in fixing the problem where it exists and not by adding an additional parameter to an already over-constrained problem.

I have my Nova II phono pre capacitance set at 100pF for my Delos and I use an AQ Cougar phono cable with total cap at 60pF. Lyra suggests using the lowest cap cable you can, and for me it does make a difference, as I was using a very high cap cable in the 350pF range with loading at 121 ohms.
The dynamics and resolution is so much better now.

Just for interest sake, I ran some simulations with an "ideal" MC cartridge with a 5mH/5 ohms coil in conjunction with a near ideal active RIAA design with non inverting amps and the extra pole.

The ideal load- the one that results in the closest compliance to RIAA
is with 22nF||110 ohms (+/-.06dB 20Hz-20kHz). It also has 50dB of attenuation (relative to the ideal RIAA stage) at 1MHZ and 95dB at 10MHz. Dropping the load R to 100 ohms reduces the 20kHz output by 0.2dB. 
Increasing the capacitance to 0.1uf and reducing the load to 68ohms is almost as good as this.
None of these simulations include the mechanical response.
Anyway- as can be seen there is no perfect answer. There are many combinations of load R/C that are pretty well equivalent and you can't even simulate or calculate it to find a decent answer as no MC cartridge maker that I am aware of provides even simple models for their device, even when asked.

Unfortunately accentuated dynamics and resolution all too often mean a really nasty peak at the HF. In my experience, getting a good test record and testing the RIAA response can be a real eye opener.
Most of the differences in response that occur due to changes in load are in the 10k-20kHz range.

Dear @wynpalmer4: " I may not be a renowned Audio Designer..."""

Problem with we audiophiles is that almost all always think that reviewers and manufacturers are the ones that not only kno everything but that what they say always is " the Bible " and almost all of us are docile followers, pity for say the least.

The other problem is that we audiophiles think we understand " everything " in audio with out take in count that all of us are ignorant people in several audio subjects when in other audio subjects our ignorance levels are lower.
Additional to that when I speak of ignorance levels peoples feel that I’m trying to offend/hit them when it’s in not way. Ignorance is just that: ignorance.

Good that you came here to put a true " ligth " in that regards because the atmasphere seller is spreading that same capacitance issue all over the internet forums and like here @krelldog is " facinated " with 47koms @catcher10 just does not understand what you posted.

We all audiophiles in reality are not educated in what is wrong or good in what we are listening at our place/home and this ignorance level is the real brake that stops the high end faster developments. Go figure, we are in 2018 still using tubes in phono stages and the real problem is that audiophiles are jumping of hapiness with. To each his owns.

""" In most cases a resistance close to 100 ohms is fine- largely because the coil DC resistance is often a proxy for the inductance .... and as a result a 100 ohm load gives you a well damped electrical system..."""




Several years ago I remember a top LOMC cartridges evaluation made it in TAS where one of the reviewers was the TAS’s editor ( that pass away. ) where as was his " trend " always loaded his LOMC at 47kohm but he did it for way different reasons where one of them was that he was losting to fast his auditive sensitivity due that for many years he listened his audio system at way to high SPL ( he had the Infinity IRS loaned from years. ) and where that sensitivity affects more is at the high frequency range that’s what shows that wrong 47kohms loading. We " love " that " transparency/spark "/detail in that range with out take in count that only are higher distortion levels. You said it:

""" Unfortunately accentuated dynamics and resolution all too often mean a really nasty peak at the HF ....... ferences in response that occur due to changes in load are in the 10k-20kHz range. """

Well, audiophiles as me sometimes we don’t like 100ohms loads because in many audio systems makes that we " feel " that the sound is " dull " but the problem is not on the load it self but in the system/room interaction and that our MUSIC/sound priorities are wrong choosed and sometimes is because we not only don’t attend often to live events but there are people that not even does one time in a year ! ! and this is a serious trouble.



"""
I’m a believer in fixing the problem where it exists and not by adding an additional parameter to an already over-constrained problem. """


with different words I posted something like that.

"" you can’t even simulate or calculate it to find a decent answer as no MC cartridge maker that I am aware of provides even simple models for their device, even when asked. """

it’s out of our control.

I’m way ignorant in several audio subjects and I wish to have a tinny very tinny fraction of your level knowledge/skills and experiences.

For my part really appreciated your posts. A learning lessons for all we true audiophiles that are always willing to learn and trying to sell nothing.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.