MC cartridge loading: still baffled


I am using a low output moving coil cartridge- a retipped Linn Troika.  Recommended loading is 100-200 ohms which I have always followed.  My phono pre is an Ayre P-5xe and set to the highest gain.  Years ago, Michael at Ayre said most moving coil cartridges sounded best when loaded at 47k ohm using their phono pre.  I just got around to trying this setting and it does sound more open and better to me.  Lately, I am discovering that much of the dogma that I have been following isn't necessarily correct, at least with my system and to my ears.  Another example I found recently is that my arm/cartridge performs just fine with very little anti-skate force as opposed to just picking a setting equal to VTF as universally suggested.

Back to the loading question:  is the proper loading more a function of the phono pre or the cartridge itself?
jc4659
The phono preamp. Having adjustable loading is great as you can play around to see what you think sounds best in your system. I would trust Ayre's suggestions on their equipment.
As for anti Skate, never follow the tonearm's instruction. You adjust the anti skate by test record or by the Schroeder method. When you put the stylus down in the run out area between the grooves it should VERY slowly drift toward the spindle. Not using any anti skate is improper and you can see this easily. Defeat your anti skate mechanism. Viewing the cantilever from the front use your lift to lower the stylus into the groove and watch where the cantilever goes. It will deviate towards the outside of the record as the tonearm leans heavily on the inside groove (left Channel.) What you are doing is increasing the tracking force on the left channel and decreasing it on the right. The right channel now starts miss tracking early. You can hear this effect easily with a test record. This also increases wear on both the stylus and the record. When you set the anti skate correctly you will notice when you put the stylus down that it does not deviate at all.  
@mijostyn thanks for the reply!

Concerning the anti-skate setting, using music as my test (not a test record), I get no right channel distortion even with the anti skate turned off!  Turntable is absolutely level.  Using the run-out  area test, sure, the arm skates when lowered into this area but tracks fine when allowed to enter the run-out groove at the end of a record.  I finally settled on an anti-skate setting ~ 0.5 just to have some counter force but using test records with atypical modulations might be overkill.  If I hear any break up coming from the right channel (outer groove wall distortion then I will adjust it higher but for now, I am quite content using this lower setting.
I should also add that I do not see any deflection of the cantilever when the arm is lowered into a groove.  However, the cantilever is not very compliant so this may be a factor.  I am comfortable using real music as a test and listening for possible break up if the antiskate setting needs to be adjusted higher.  I acknowledge the possibility that I might be wearing the stylus or inner groove unevenly.
Mijo forgot to mention that your empirical finding that you need much less AS force, in terms of grams, than VTF is absolutely to be expected.  The notion that if VTF = 1.5, then AS = 1.5 is antiquated.  Setting AS = VTF will nearly always result in an excess of AS, which you can hear in the form of L channel distortion. So, you did good.
Likewise for the choice of resistive loading.  First, as Mijo said, you are always well advised to go along with a manufacturer recommendation, and second because loading is for the phono stage more than for the cartridge.  You might want to search the long and contentious thread on cartridge loading for posts by Atmasphere, who explains this well.  I too have found that 47K sounds more "open" for me, using an Atmasphere MP1 phono section with one or two of my LOMC cartridges.
Anti-skating force depends on the stylus profile too, with advanced profiles it's never equal to the tracking force, normally lower. I remember VdH interview and his thought about it. 

Regarding the loading just buy a phono stage with optional loading and use what you like, do not listen to anyone. 
Back to the loading question:  is the proper loading more a function of the phono pre or the cartridge itself?
Ayre made their recommendation to you on account of the fact that they did the proper homework in their design of their phono section.


There is another thread active on this forum that relates to this topic. So I am repeating myself here:  The loading resistor is primarily for the benefit of the phono section, not the cartridge (although decreasing the load resistor value will decrease the compliance of the cantilever). The cartridge has an inductance and the tone arm cable (and to a certain extent, also the input of the phono section) has a capacitance. They are in parallel. Anytime you find an inductance and a capacitance in parallel you have a tuned circuit, also known as a 'tank circuit' (as it stores AC energy) which resonates at a certain frequency. BTW an inductance in parallel with a capacitance is the means used to tune a radio to a station.

Since the inductance of a moving coil is usually slight and capacitance of the cable is also low (or should be) the resonant frequency is rather high and can be anywhere from several 100KHz to several MHz. This resonance is a peak and can be as much as 30dB! When the peak is at resonance, the term for this is 'excitation'. The energy of the cartridge itself is enough to drive the tank circuit into excitation.


Essentially as far as the phono preamp is concerned this energy is RFI (Radio Frequency Interference) and is injected directly into the input of the phono section! It can overload the input of the phono section and this can result in a tick or a pop. So to avoid this problem the input of the phono section should be designed with plenty of headroom.


The loading resistor suggested is in parallel with the tank circuit. It acts to detune the tank circuit and prevent resonance. Since a cartridge manufacturer has no idea of how competent the phono section to which the cartridge is connected will be, they often recommend a low loading value to allow that phono section to operate correctly. Its well-known that RFI causes audio electronics to not sound right (often brighter)!


But if the phono section is RFI immune and has good overload margins, the loading resistor simply isn't needed. This allows the cartridge greater compliance and can result in better tracking performance, depending to some extent on the tone arm. Right about here things get a bit complex, but as a general rule of thumb most cartridges are designed to drive 47Kohms, despite the 100 ohm loading recommendation.

The bottom line is try it both ways and see.
@atmasphere  thank you for (repeating) your thorough explanation!  

Thanks to all for your input as well!

JC
Jc, if your anti skate is not set correctly the unloaded channel will only miss track at higher groove velocities so at regular velocities things might sound sort of normal. But, there are more than tracking considerations. For the best performance/low distortion the coil (or magnet) should be placed symmetrically in the magnetic gap. With the anti skate set incorrectly the cantilever will drift to one side or the other and this will not be the case. Again, in the run out area, between the grooves the arm should drift VERY slowly towards the spindle. Use whatever weight or setting of your anti skate that accomplishes this. This will assure you of the lowest distortion, best channel separation and best tracking your cartridge can achieve when it hit the cannons in the 1812 Overture. 
It looks like there are some knowledgeable people on this thread, so I'll take the opportunity to add a few questions.

1. Can someone suggest a good test record?
2. Is tracking force adjustment for 33 rpm just as suitable for 45 rpm records.
3. Is the best tracking force for the outside of the record the same as for the inside and should tracking force be adjusted in the middle as a compromise?
1.  There are at least a dozen useful test LPs.  Depends upon what you want to test for. The Cardas LP is a good one to have.2. Yes.3. Are you kidding?
Another way to set AS: Start with the very lowest amount that your tonearm permits, but not zero.  Gradually increase from that starting point until you have no audible tracking distortion in the R channel.  (R channel distorts with zero AS, so you want the minimal AS that eliminates any such issue.)  Others will have other views.  This is no more nor no less vague than Mijo's method.
Both loading and anti-skate are set by ear. I only just recently learned the difference a small adjustment can make. Anti-skate on my Origin Live Conqueror is a ball hanging from a thread attached to a lever arm. A little set screw lets you slide and lock it in.

I’m guessing somewhere along the line that screw got loose and it slid out resulting in increased anti-skate.

Hard to say. Its not like there’s markings or anything.

Anyway, it never got far enough off for anything as obvious as breakup. I’ve always thought of that as the marker, and so assumed mine was fine.

Until gradually over the last few months I was getting this funny feeling the image was ever so slightly right shifted. Some vocals that I was sure had been rock solid dead center seemed just a tad to the right. I’m a freaking OCD stickler with speaker placement so that’s not it.

I started thinking. Its to the right. The right channel is the right side of the groove. Even without mistracking, too much pressure would have the coil ever so slightly off center. Well you can think or you can find out.

I found out. A little less and not only did the image shift that few inches, it locked in a good deal more solid too. Not like it was ever bad before. Far from it. Which is why I never tried before. Never, ever would have dreamed of setting anti-skate by ear like this before.

Its amazing the extent to which these things can be tuned with enough time and tweaking.


I use a blank record to adjust anti-skating. You can get a one sided recording on ebay . It works for me!!
https://www.bing.com/videos/search?q=anti+skating+with+a+blank+record&&view=detail&mid=B...

@millercarbon always disheartening to realize you've got a loose screw!  ;)  I'm going to try the center image test on some recordings that I know to have a dead center vocal image.  I am also OCD about speaker positioning.
Actually Lewm that is Frank Schroeder's method. I prefer to use the HI Fi News test record as it has an excellent anti skate track and both vertical and lateral resonance tracks. But I have noticed repeatedly that once I set up the tonearm with the record the tonearm drifts slowly towards the spindle on a blank record so Frank's method works. 
When using the test record you are using your ears to detect miss tracking.
I can't count the number of screws millercarbon has loose. Setting up a system is simple once you know what you are doing. The vast majority of "tweaking" is mythology. A really good tech can interpret what a client wants to hear into the system's sound. 
Good post on anti-skate! Learning never gets old. Thank you all!
Yogi, blank LP is not a good tool for setting AS. The skating force is due to the friction of the stylus as it passes over the vinyl in the groove. A blank LP by definition has no grooves. Therefore, it does not present the same friction related resistance to travel as does a real LP with grooves. This has been stated and restated over and over again on various forums.
While I agree with your conclusion, the number of falsehoods being stated on various forums as facts are as numerous as the grains of sand on a decently sized beach.
lewn,

The blank disc is NOT intended to simulate actual operating conditions.  From experience of many manufacturers and listeners, it gives a rough approximation of what the correct setting would be when playing actual records.  Like all antiskating measures, at best, one can only get a roughly correct setting--actual skating forces change dynamically during play (tends to be higher at high modulation levels) and this methodology is intended to roughly mimic the forces when playing records at average modulation levels.  I think SoundSmith has a video explaining this approach.  

I use to set antiskating using test records (like the Shure trackability test records) with music played at higher and higher levels and I would set the antiskating at a level that minimizes mis-tracking or cause the mis-tracking to be about equal in both channels, and then I would back off antiskating from this level just a bit to account for the fact that I never have records recorded at such high levels of modulation.  I now just use the blank record approach (much easier).
Dear @larryi  : 2+   lewm: 2-

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.
Raul seems to be my personal critic, following me around on these pages to disagree or debunk what I might have written.  Raul notwithstanding, I have no problem with anyone setting AS any way they want to.  I was merely re-quoting a fact: blank LPs do not generate the friction force on the stylus tip that is generated by any LP with actual grooves encoding music.  This is not a truth that emanates only from me; others have also mentioned it.  Raul or anyone else can take that or leave it.  Nor do I dispute the fact that the skating force is constantly varying across the surface of an LP, largely in fact due to groove tortuosity and also to the constantly varying tracking angle error.  Thus, there is no such thing as one correct amount of AS, even for any one single LP.
raul, I didn't know you knew how to do math:)
A good explanation of the blank record and the similar use of the run-out section of the record can be found if the last listed video here:

https://www.sound-smith.com/articles/videos

This is the method now endorsed by Peter Ledermann and Frank Shroeder (tonearm maker).  It is also the method described in the instruction manual of one of my cartridges (I believe it is the one for the Lyra Titan, so J.C. Carr is also endorsing this method). The video explains why this is a reasonable approximation.  

Someone mention listening for how well centered is a soloist on records with a well-defined center image.  To me, that would work only if your cartridge had perfect channel balance and few owners are that lucky.  I would rather have the cartridge set up for optimum physical alignment, and compensate for channel imbalance with the balance control on my linestage.


@lewm
I stated that a blank record is what works for me. I hear a large improvement in the stereo image when I use that method.  I could care less what is said on other forums. You should give it a try!
lewm doubt your keeping score, but I have to give you
1 point for tortuosity. :)
I would guess that using a blank LP would give you a baseline for AS force, because I am guessing that the skating force on a blank surface would be a bit less in magnitude compared to that of a stylus traveling in a groove, where the contact points are to the side walls of the groove.  Whereas on a blank LP, the very tip of the stylus is all that would contact the vinyl.  Plus, the stylus is not having to negotiate tiny undulations due to the recorded signal. So, maybe less skating force.  If all this is so, then the blank LP could give a good baseline from which one might need to add a bit more AS force for playing LPs.  I dunno.  I certainly never meant to say it is dead wrong to use a blank LP, but I prefer either Mijo's suggested method (using the run-out grooves) or my own, which is apparently also the approach recommended by Frank Schroeder.  (At least I am in good company.)  I think this is enough tortuosity for all of us.
I am using TW ACUSTIC RPS100 which has multiple loading options.These loading options can be selected from the front of the unit.The phono is tube based 2 6dj8s and 2 12ax7s.The loading is determined by the cartridge.
too bad Michael has retired and went to Florida....I always enjoyed talking with him.  I'm using an Ortofon with Ayre, and after experimenting (a pain with most, but Ayre has those screw in connectors for resistors) I found 10K to sound better to my ears.  I would always say to satisfy your own preferences.  ( Gary has replaced Michael....another great guy)
Another person here who used to just follow cartridge manufacturer's recommendations for loading, but 47k sounds best with my Hyperion/NuVista Vinyl and Herron VTPH2A.
Using a DV 17D2 in a Rega RB300 with the AS set to match the VTF resulted in an offset and twisted cantilever after probably a bit too much use. I then got a copy of a record called “the enjoyment of stereo” in a job lot of classical records I was given. This had a track for setting antiskate which was a blank section of the disk near the halfway point and it’s proved very useful over the years.
At one point I had an arm with weight and thread AS (Naim Aro) where the thread could only go in a small number of grooves to adjust it, it was easy to hear which one sounded best.
Now with a Schröder Reference arm and I’m back to the blank record with a bit of fine tuning by ear. The hifi news and record review test record tracks result in far too much AS.

Loading I also assess by ear but as suggested above it doesn’t seem to transfer between phonostages Ω for Ω. If you like 47k on the Ayre compare it to the next lower setting and so on, you’ll soon form a preference or, if you don’t, it doesn’t matter.
 Reviewing this thread, what surprises me is how many other people besides myself have empirically discovered that they prefer to use a 47K load with one or another LOMC cartridge. I arrived at the conclusion that I preferred 47K quite by accident, speaking for myself. And I previously thought that I was a loner in this regard.