Cartridge Loading- Low output M/C


I have a Plinius Koru- Here are ADJUSTABLE LOADS-
47k ohms, 22k ohms, 1k ohms, 470 ohms, 220 ohms, 100 ohms, 47 ohms, 22 ohms

I'm about to buy an Ortofon Cadenza Bronze that recommends loading at 50-200 ohms

Will 47 ohms work? Or should I start out at 100 ohms?

I'm obviously not well versed in this...and would love all the help I can get.

Also is there any advantage to buying a phono cartridge that loads exactly where the manufacturer recommends?

Any and all help would be greatly appreciated.

Thanks in advance.
krelldog
Dear @almarg and friends: This came for the very first post by Wyn:


""  the bottom line is- you’ll never get it perfect. You can either listen and decide what you like......... A couple of other things, the RIAA deemphasis of your amp comes into play, and it’s not unusual for that to be off c. 0.5dB or so over some frequency range, and most amps have restricted frequency responses to reduce the infrasonic and ultrasonic signals.
Also, your room/speaker response is probably poor with errors at least as large as any from the above sources, so unless you’ve characterized and corrected that then listening is probably your best bet. """


and then from the others posts these hiligths:

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


"""  Unfortunately accentuated dynamics and resolution all too often mean a really nasty peak at the HF. In my experience......... 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. """

"""  Again, listening is best, but be careful not to delude yourself.
Audiophiles (myself included) tend to get seduced by what are essentially deviations from what the real listening experience provides- such as excessive detail, ability to resolve supposed room artifacts etc. etc.
These effects, in my substantial experience of live performances, just do not exist in a live listening environment,..."""


"""   take the Madake for instance- the resistive load that people (reviewers) claim is best literally varies by nearly four orders of magnitude! I load mine with 60 ohms (as do many users) and I find that the resolution and dynamics is excellent while maintaining a natural timbre, tonal balance and micro/macro dynamics while not creating the unnatural etched image that many "high resolution" MC cartridges produce.   """


"""  increasing the R to 47k shows significant near-oscillation at the output of the preamp.
The passive design shows none of these pathologies with the change in load R, and always has a significantly slower and essentially constant, risetime,......................................................................................................................... perhaps the answer to the loading question is, no matter how unlikely it seems- it depends on the architecture of your phono   """


Everything he posted is full of lessons for me and maybe for some other readers.

Is important for me read those highligths that gives a more " affordable " information for all and important to note his " perhaps " in last higligth.


This thread made that I remembered one time in one of my trips to USA when in an audiophile place whom owned a top system/room audio system ( 150K-200K $$$. ) I attended and when we were listening his system I noted something was wrong with the tonal balance of his LOMC cartridge .
His system in those times ( between other items ) had: Walker TT, Dali top of the line speakers, tube monobloks amps, first rate cables everywhere, very good room treatment many audiophile tweaks and a four chasis all tube phono stage ( no SUT. ).

Mi first question to him was the value of the load he was using where I ask him to lower to at least 100 ohms and he did it ( he was loading it at way higher R. ) and ligths come out " and he noted at once as I did it." 
Everything changed for the better. Over the time my experiences with my and other systems attest the same behavior ( tubes and SS electronics. ).

Al, I posted to you that the capacitance issue is almost useless when exist several other critical subjects we have to fix in our systems before that.
As Wyn posted: "  so unless you’ve characterized and corrected that then listening is probably your best bet. """ followed by:
""" 
fixing the problem where it exists and not by adding an additional parameter to an already over-constrained problem """

Analog is full of " problems " and " problems " of more vital importance that the capacitance issue and are on those " main problems " where we have to work before other " new " parameter.

If I remember years ago (but I'm not sure if he was. ) I read probably in the long MM thread a JC post telling that for capacitance could has an audible effect with LOMC cartridges the amount of capacitance must be truly high. This was the second time that I read it ( first time somewhere in the net. ) . As I said not totally sure if was JC but was in Agon. I really never bother about as I don't bother yet.

As @krelldog and @catcher10: " 
There is a tremendous amount of info here, both super technical as well as the basics """.


R.


One other thing, setting the input resistance >>100 ohms can have unfortunate effects on the input stage amp if the bandwidth is high. For example, with a AD797 opamp the gain bandwidth product is 110MHz, so for a c. 2.5MHz electrical cartridge resonance  the amp still has a gain of 44, so if the input stage has a high gain the total gain at resonance can be 35+32dB=67dB, or a gain of about 2k, so if, for example, there's a transient click which generates a 1mv rms output at resonance the input amp can produce 2v rms output.
This may not be an issue, but it would seem to me that when using a high resistive load an input amp with either a very high overload margin or a deliberately limited bandwidth (<<2.5MHz) would be essential. Once again, preamp architecture seems to be the deciding factor.
This may not be an issue, but it would seem to me that when using a high resistive load an input amp with either a very high overload margin or a deliberately limited bandwidth (<<2.5MHz) would be essential. Once again, preamp architecture seems to be the deciding factor.

It is an issue, as far as I can tell. Overload margin is really important otherwise ticks and pops abound.

When you cut a lacquer, if the stylus angle and temperature are set right, the silent groove is so quiet that the playback electronics are the noise floor. The test LP you get back from the pressing plant comes with a form that the producer has to sign- so the test LP gets a listen to insure an absence of ticks and pops. So it follows that most LPs should be nice and quiet, and in practice if the phono preamp is up on its game, they will be.
I don't have the values you requested, but the coil at the output of the cutter amps isn't very large. The inductance of the head varies depending on the voice coil used and we've used both. The older version use a series resistance, while the newer ones are higher impedance (about 10 ohms) and don't employ the resistor. I suspect this could be handled in a better way, as well, the cutter amps were designed in the late 1960s- they are pretty primitive!


Well, the preamp design that I've been referencing has an unweighted 20-20kHz S/N ratio of 66dB at 1v rms output, 0.25mv rms input. Assuming the 0.25mv output from the cartridge is at 5cm/sec, and the max velocity before miss-tracking is 20cm/sec the effective dynamic range of the preamp is 78dB, unweighted. 
I don't have any LPs which do not noticeably increase the noise floor once the stylus is dropped, but that could mean that the LP dynamic range could still be >70dB weighted. For the passive design the gain is split c. 200x for each of the two gain stages- which produces c. 50mv rms at the output of the first stage and c.1v rms at the final output due to the attenuation through the passive equalization network. 
The amplifier GBW product provides the necessary roll off to prevent overload and the output noise is imperceptibly different between the passive and active designs. The active design measures slightly better as far as harmonic distortion is concerned, but were talking about the difference between 0.001% @ 1kHz, 1v rms,versus 0.001% @ 10kHz, 1v rms as at lower frequencies noise dominates and I can't measure it with my primitive test equipment.
If I add a 42kHz cutter -3db point, then not surprisingly, the 20kHz response is down by c. 1dB.
I'm using the opamp preamp for three reasons- I can simulate it quite well, it sounds, actually, pretty good, and it's easy to make changes in topology to examine various aspects of the design to investigate various things- such as the mystery of loading.
Dear @wynpalmer4 and friends: Other that your very clear higligths I posted other gentleman posted in this thread:

"  If your set up sounds "wrong" with more modest loading, such as 100 ohms, something might be wrong elsewhere..."""

I don't know why all those " huge " inistence on the capacitance LOMC subject maybe because one of them is a seller .

Now, you are a gentleman that already use around " 100 ohms as loading the LOMC cartridge and in the Madake 60 ohms with great results.

I experienced always in the same way however a " live " evaluation tests are in order and as always I just did it because it's the best way to learn something new or confirm our believes.

I have my own fully proccess to make audio items evaluations in my system through listening sessions.  My tests evaluation was changing only one parameter that's the cartridge load impedance going from my usual 100 ohms to 47kohms and 100kohms. Fortunatelly I have that proved proccess ( tested in my system and many other diffrenet systems. ) and a truly high resolution and precise system. Well this is what I found out against 100 ohms:

I found out no more transparency or openess in the system presentation in those HF range but what I heard is lower " definition " of the fundamental and developed harmonics even in some of the tracks of that test proccess part of the detalied HF with 100 ohms not only was veiled but just disappeared. The transient and decay time changed in a way that makes everything more " ethereal " than with live music definition.
The overall presentation at 47/100k has a penalty not only in the HF range but even at the lower ranges maybe because the " contrast " in between goes smaller but I can't be sure why.

Taking those Wyn highlighs and  the larryi ( now I remember whom posted the highligth at the begin of this post. ) I agree with both of you and what larryi said is true " something wrong " in the system.

Seems to me that some of you that prefer 47K with out intention to do it what in reality are doing is " compensating " some " faults "  somewhere in the audio system links of that complex system chain and could be problems in more than one of those system links.

My take is that before we make changes on LOMC cartridge loading and especially from 100 ohms to 47K we have to be totally sure that at every single system link we have no " problems " but if you are unaware of that then you have to make a proved testing evaluation using a proccess that permit a " true " evaluation. Obviously that we can't be absolutely sure of the proccess validity but we have to be nearer to that " true ".

Is more frecuent/often that we make changes where we don't need to do it but anyway we did it and think that were for the better when in reallity are only hidden system " errors " somewhere.

Of course that for those evaluations we have to be honest with our self and not biased on purpose or because we are accustom to this or that characteristic in the sounds and obviously that we have to be sure that we know how sounds each instrument in a near field live event.

Btw, I made my tests as always: at normal seating position and at near field position. As a part of my proccess tests headphones are inside but normally I don't use it because I'm truly engaged with the system but this time I used and confirms what I said. I always prefer the near field test than the headphones because I'm not accustom to.
Btw, I tested through too using an additional full stage with my AU-1000 SUT with similar results that in the active high gain phonolinepreamp.

Now, sounds bad at 47K? no it did not but when you are accustom to the top quality level I'm the you can listen the difference at once not 3 hours latter, it's immediatly.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.