Cartridge Loading for a phono pre amp

Thanks @atmasphere .

I was under the impression that the current from the motor was the same with and without the load, so 47k would be a higher voltage across the resistance, and lower resistance would be less voltage.

Looks like I got it backwards.

The options I have are as follows: 47K, 1K, 560R, 470R, 100R, and 47R.

There are three more options worth experiments:

257R (560R+470R)

322R (1K+470R)

362R (1K+560R)

 

Also ... with an output of 1.1 you might start at 52 db of gain.

Always start with 47K to see if the preamp works with RFI at its input. If yes (the preamp is unperturbed by RFI), this will get you the best sonic performance. If it sounds better with lower resistance loads, then the preamp does not handle RFI well.

Dear @judsauce  : Start with Benz advise at the end is the cartridge manufacturer and knows all around cartridge/tonearm/phono stage to achieve the best of each cartridge. So you can  start with 470 ohms and test it with LP tracks that you know very well what should be its quality performance levels.

MF loaded his Cadenza Black in your phono stage review at 100 ohms and even at 47 ohm and he did not mentioned any single quality level bad performance because that cartridge loading.

 

Btw, @holmz , next  I pasted what J.Carr ( Lyra cartridge designer ) posted about cartridge loading:

"" To claim that the loading affects the measurable frequency response of the cartridge is bogus. However, if inappropriate loading bathes the phono stage in copius amounts of high-frequency noise, it may start to distort (unless the designer implemented various techniques to make sure that this won't happen), and the result will likely be intermodulation distortion.  ""

""  If the phono stage does not have high overload margin at ultrasonic frequencies, or not-so-favorable linearity at ultrasonic frequencies, the ultrasonic spike resulting from high-value resistive loads (the spike can be in excess of 30dB at 5-7MHz if the phono stage input termination is 10kohm or higher) can easily result in ringing and intermodulation distortion which will obscure real information.

But if the designer does give his phono stage high overload margin and good linearity at ultrasonic frequencies, the phono stage will treat the ultrasonic spike as simply another signal, and no intermodulation distortion products will be generated that could otherwise be low enough in frequency for the ear to hear.   ""


He never posted that loading to hard a cartridge will cause stiffness to the cartridge cantilever enough to mistracking.

What I pasted is a JC conclusion with foundation in his white papers coming from 2018 where  made a in deep analysis, modeling/simulations, with white papers including charts of the behavior of loading an LOMC cartridges with different impedance values along different capacitance values too.

 

Other gentleman that in the past works for Analog Devices been group leader there and where he made/designed  several AD items proved in real time what JC said and that does not exist cartridge frequency response anomalies in any way:

 

""  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.

 I did not design the AD797. That was Scott Wurcer- a colleague at ADI ( Analog Devices competitor to TX/B&B ). and, incidentally, for whatever it's worth, also an ADI design fellow. However, I know the design quite well.

He and I were colleagues in the opamp group in the 80s. He focused on high performance relatively low frequency opamps such as the AD712 and then the AD797, amongst others.

I focused on high performance high speed amps like the AD843, 845 (at one point an audio darling), 846 (also a transimpedance design with some very interesting design aspects that I gave an ISSCC paper on) etc. etc. mostly using a complementary bipolar process that I helped develop that I believe was also used in the AD797.
 I also did things like designing the FET based AD736/737 RMS-DC converter and others.
I moved on to more RF, disk drive read/write, GSM, CDMA etc. transceivers, signal processing, PLL and DSP designs. Then he continue:

 




""  is why any of the purported effects of heavy resistive loading you state could be definitively true-

 certainly NOT on TRACKING which is demonstrably FALSE based on IM tests on tracking performance that I have incidentally performed as a function of load.

  ( He measured and is the only gentleman I know he did it. )

While mechanical impact does occur as a result of electrical load- there is some back emf necessarily generated by the signal current that affects the mechanical motion, but a quick back of the envelope calculation using Lenz's law and the 10uH cartridge suggests a 2 orders of magnitude difference between the generated signal and the back EMF for a 100 ohm load at 20kHz- certainly not enough to cause tracking issue.

 As for the rest, well, 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.

By the way, I constructed a model for the cartridge back EMF using Lenz's law and incorporated it into my simulations.

One of the "joys" of being an IC designer is the compulsion to measure/model everything! However, once the skills are developed it's relatively easy to do as long as someone else has done the hard work of producing suitable models to use.  "

 

All those by this gentleman and J.Carr are facts, something proved not coming from theory or a book.

 

So, the next statements are totally false and a falacy:

 

"  it will make the cantilever stiffer and less able to trace high frequencies. It can and does affect the interaction between the arm and cartridge (effective mass and mechanical resonance).  "

 

@holmz  , not only were proved the statements are totally false but who posted the statements never posted anywhere where he is sharing that false information any tests/measurements/facts to prove it and always only dead silence and not only that but it's just a little of common sense to know that information is false:

 

first effective mass is not affected and the existence of  mechanical resonance for that false " stiffer " cantilever just can't happens at a level where can has a measured effects. Look, if we take a tonearm with 12gr. on EM and a cartridge with say 18cu on compliance and 10 grs. of weigth the tonearm resonance frequency is: 8hz..  Now, you have to change the cartridge compliance from 18cu to 15-14cu ( stiffer ) to change the resonance frequency to 9hz but that does not affects high frequencies.

 

It will be an stupidity by my self to follow post arguments against something false when exist real test/measurements that already proved are false..

 

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.