A moving coil is generally loaded 10 times it’s impedance. The Hana EL for instance has an impedance of 30 ohms, so 300 would be a good place to start. Hana recommends loading the EL @ 400 ohms or greater. I own it and i run it with a Jensen SUT which incidentally has an impedance of which the cartridge sees of 430 ohms. This particular cartridge sounds wonderful any where between 400 a 475 ohms. Lower (numerically) impedance loading will result in an accentuated bass response and the cartridge will sound closed in. Higher loading will result in a brighter sound but also more open. My Rothwell mcx SUT will provide a fixed load of 100 ohms, ideal for many a moving coil, such as my Goldring Eroica LX, which the manufacturer recommends it be loaded at 100 ohms.
I do not subscribe to loading a moving coil at 47k, I reserve that for my many moving magnets.
What is neat about my pro-ject tube box DS2 is that I am able to dial up any impedance loading so desired on the fly from 0 to 1000 ohms.
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As Ralph ( @atmasphere )has pointed out many times loading is for the cartridge preamp system as a whole, more for the preamp than the cart. So every combo has its sweet spot.
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Now that I have better designed phono preamps, most of my MC cartridges sound better at 47K loading. There are a couple, especially my Denon 103R that sound better with lower loading, but I like the 103R at 1.6K rather than 100 or 400 ohms.
Since changing loading can't hurt the cartridge or the rest of my system, I'm happy to experiment with all the different settings, regardless of what's considered correct.
FWIW, I like some of my MM carts at 68K rather than 47K. I wish I had 100K to try easily.
Bottom line, I trust my ears.
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Dear @quincy : " My take from this recent thread is as follows. Load at 100 Ohms or at 47K Ohms with a quality MC cartridge. "
No, it's not that way. Your phono stage has several load choices from 200 ohms to 47k and what you have to do with both cartridges as the Delos is to test the quality performance in your system starting at 200 ohms and then change to the other choices till you decide which load is the one that fulfill what you like the more.
This is the Lyra J.Carr cartridge designer Delos load advice:
" Recommended load directly into MC phono input: 97.6ohm ~ 806ohm. )
Btw, " all those years listening to the incorrect load setting.. " :
no, was not incorrect according with Lyra 500 ohms is inside a " correct " load impedance range Lyra advise.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.
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I'm not an experienced pro, nor a technical engineer: the instructions on my MC just recommend about 10x cartridge impedance, and, as @rauliruegas indicates, the instructions on my Lyra cartridge recommends anything between 100 to 1000 ohms.
The phono stage (Manley Steelhead) recommends just listening to the cartridge at various loads, and pick what sounds best.
I don't know what implications there would be with a SUT.
I suppose this is all variable, depending on the capabilities of the phono stage, as Ralph @atmasphere seemingly explained in the previous thread.
Best wishes to everyone, and I hope everyone is enjoying their music.
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Ultimately it depends on your ears. There really isn’t a “right or wrong”. Personally, like others I have found 47k to be way to bright/harsh when tried. I have usually settled into more of a “loaded” sound than “unloaded” as I prefer the generally beefier low end. That’s my preference. Have fun with it. One day you might like X loading, the next Y… makes it fun.
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Just to share: my Lyra Kleos sounds best anywhere between 60 to 500 ohms depending on recordings (overly dark ones at 500, overly bright ones at 60 and 400 for most, that's why I love the PS audio stellar phono preamp with its instant ohms adjustment on the remote). However the changes are not very significant. On the other hand, my new Sumiko Starling sounds best between 100 and 280 but changes are much more significant. Anything 300 and higher, count me out since it loses its slam. BTW, love this cart, much more fitted to my "head banger" style of music than the Kleos. Term often referred to here by some and always by my wife at home 🙂 That's why I built the house of stereo. Now you know.
Kleos for acoustic and classical, Starling for everything else in my setup.
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I am running a Benz Micro Wood SL and have it loaded at 150 Ohms which I thought sounded best after some trial and error. The specs for the cartridge list >100 Ohms. I tried 47K Ohms and as others have experienced I found that setting to be harsh and the music lacked cohesiveness. My Phono Stage is a Herron VTPH-2A and has load resistors that plug in the back so experimenting is easy as long as I have the proper loaded RCA's to experiment with. I also have the ability to custom make different load resistors if I am so inclined.
Chuck
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I don't know what implications there would be with a SUT.
I suppose this is all variable, depending on the capabilities of the phono stage, as Ralph @atmasphere seemingly explained in the previous thread.
Normally you have a rather prodigious electrical peak (resonance) with a LOMC cartridge. It might be as high as 5MHz or as low as 100KHz. Generally speaking if a lower frequency the peak will be less prodigious; this depends on the Q (Quality) of the coil in the cartridge. Lower output cartridges tend to have a higher Q since the windings are shorter and wider with respect to their length; this done to keep their mass down.
That peak can be a good 30dB (1000x) higher than the signal! So if you have a 0.5mV output, perhaps half a volt at 2-5MHz is presented to the input of the preamp. Some preamps don't like that (and might sound bright or weird as a result)! For example, if the phono section employs high quality opamps, its quite possible that the circuit will have some bandwidth that that frequency and so could be overloaded (if overloaded, you'll get ticks and pops) or otherwise affected by an RF signal that powerful at its input!
That's why the loading resistor can be so important (its used to detune that peak, thus eliminating the RFI it generates)! Its certainly not to change the bandwidth or frequency response of the cartridge; at least with all the LOMC cartridges I've tested, all showed no ringing at audio frequencies- quite simply their inductance is too low for that, which implies that the load isn't needed to roll them off to prevent brightness- therefore something else is causing the brightness.
When you use an SUT, it simply lacks the kind of bandwidth to pass RFI at 200KHz or 3MHz- whatever the cartridge might be generating. The only thing with SUTs is that since they have a fairly high inductance, they need to be loaded to prevent ringing ('ringing' is distortion, caused by overshoot of the signal and causes brightness and harshness). If you have an SUT designed for your cartridge, the 47K might be a proper load so no worries. 'After market' SUTs like those made by Jensen Transformers are a different matter. They require specific loading that varies according to the source impedance of the cartridge (since a transformer transforms impedance, the correct load at the output will vary depending on the source impedance). They publish the values needed for a particular cartridge in a pdf file available off of their website. IMO Jensen Transformers make some of the best SUTs available.
I suspect that since the RFI issue is conveniently eliminated when using an SUT that this is why some people say that cartridges sound better when played thru them. Personally I don't find this to be the case, but the preamp I use has no issues if RFI is present at its input and can't be overloaded by that RFI, even if its at 0.5 Volts.
So where this is going: If you have no SUT and 47K sounds bright, you need a loading resistor to eliminate the RFI at the input of the phono section. IOW the brightness isn't the cartridge being bright.
If you have an SUT you do need to investigate the issue of its loading, which might be satisfied by the stock 47K input load of your phono section. BTW, if the SUT is designed for that and you try to drive a 100 Ohm load, you'll find it quite rolled off! There is something called 'critical damping' that applies to things like SUTs (and other interstage or line level audio transformers). If you are loading above critical damping there will be ringing causing the transformer to be bright; if you load with a resistive value too low the transformer will be rolled off.
All phono cartridges are generators, having a coil that interacts with a magnetic field. If you have a regular generator making AC power, for example a portable Honda generator for backup use or camping, you'll notice that when you load it more the engine has to work harder to keep the generator (or alternator) spinning. This is because electrical energy has to come from somewhere ('free energy' is still the stuff of conspiracy theories) so the generator presents a harder load to the engine when its asked to make more current.
The same thing happens in a phono cartridge- the lower the resistive load it drives, the harder it becomes to move the stylus since that is where the mechanical energy is input to be converted to electrical energy. IOW the cantilever becomes stiffer. If you have a means of testing the mechanical resonance of your arm/cartridge combination, you can see that this affects the mechanical resonance since in essence you are reducing the compliance of the cartridge.
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@atmasphere
Thanks for the detailed explanation. It's going to take me a while to digest all that information!
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30dB is actually 29.54x higher than the signal.
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@atmasphere I have been pondering a experience I had recently where a SUT was brought along to a demonstration that was said to be the ideal match for the Cartridge used in the system.
Prior to the SUT being used other models were used and a Phasemation Degauss Device was used, to prepare a condition that was consistent.
When the ideal match SUT was entered into the system, I was immediately astonished at how I was perceiving the presentation as being effortless and free from constraint, in comparison to the other SUT Models.
There was an Alchemy beyond my understanding.
The description on offer from yourself, might just have made me a little more aware of what I was experiencing.
I have made the post available to my Local HiFi Group to ponder over, I'm sure there are few who will enjoy your descriptions and take from it a lesson learned. 👌
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I run my MC cartridges into my Herron VTPH-2A with no loading according to Keith's reccomendations. My Lyra Delos and my other cartridges sound better all around compared with any loading including 47k.
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Been following the cartridge loading threads with interest. I have a VPI Prime, AudioTechnica ART9 MC and Supratek Chenin which has a cart loading slider switch where I can change values while playing LP's - 47k, 1K, 100 and 10 setpoints. Used 'As falls Wichita so falls Wichita falls' excellent ECM recording.
At 47K the center soundstage more defined, and background sounds more volume and integrated into the soundstage fabric.
My take-a-way is the cartridge, the pre-amp and your tastes in sound all partners in the setting that's best. For me 47K.
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Dear friends: LOMC cartridges are not sensitive to load impedance but exist a relationship between the cartridge internal inductance and the overall capacitance with the phono stgae/IC cable that are the ones that could change the " color " of what we listen with changes in load impedances.
Why active high gain phono stages does not comes with fixed 47k impedance? because is not the standard for a LOMC but more for MM/MI cartridges. Normally active high gain phono stages are designed and comes with choices with load impedance between 50 ohms and 1k impedance values. Yoday phono stages designs comes with high/healthy overload(headroom levels and really has not problems .
So, we have not to distress about LOMC load impedance just tests the alternatives that has your phono stages and set up the one that fulfill your needs. There is no correct or incorrect choice about and no you can't have compliance changes with load impedance changes that could be higher enough for you can detect or for you have to be worried about, no distress other way of thinking is just bs.
Next, the first hand experiences of almost all of you audiophiles about:
""" Benz Micro Wood SL and have it loaded at 150 Ohms which I thought sounded best after some trial and error. The specs for the cartridge list >100 Ohms. I tried 47K Ohms and as others have experienced I found that setting to be harsh and the music lacked cohesiveness. """
"" I do not subscribe to loading a moving coil at 47k, I reserve that for my many moving magnets.
What is neat about my pro-ject tube box DS2 is that I am able to dial up any impedance loading so desired on the fly from 0 to 1000 ohms. ""
"" specially my Denon 103R that sound better with lower loading, but I like the 103R at 1.6K rather than 100 or 400 ohms.
I'm happy to experiment with all the different settings, regardless of what's considered correct.
FWIW, I like some of my MM carts at 68K rather than 47K. I wish I had 100K to try easily. "
""
indicates, the instructions on my Lyra cartridge recommends anything between 100 to 1000 ohms.
The phono stage (Manley Steelhead) recommends just listening to the cartridge at various loads, and pick what sounds best. ""
"" like others I have found 47k to be way to bright/harsh when tried. I have usually settled into more of a “loaded” sound than “unloaded” as I prefer the generally beefier low end. ""
"" my Lyra Kleos sounds best anywhere between 60 to 500 ohms depending on recordings (overly dark ones at 500, overly bright ones at 60 and 400 for most, that's why I love the PS audio stellar phono preamp with its instant ohms adjustment on the remote). However the changes are not very significant. On the other hand, my new Sumiko Starling sounds best between 100 and 280 but changes are much more significant. Anything 300 and higher, count me out since it loses its slam. ""
R.
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Well, this has been an interesting thread.
I do appreciate everyones response in regards to loading.
I did a little internet search and here is what I came up with in regards to loading.
I am quoting from Analog Planet, a site of which I've never heard of prior to today.
"The Delos, machined from solid aluminum billet, features a 2.5µm x 75µm Namiki microridge line contact stylus, a solid boron cantilever and coils of 6-N high purity copper. Output of the 7.3 gram cartridge is a relatively high 0.6mV@5cm/sec while internal impedance is moderately low at 8.2 ohms. Like other Lyras the Delos uses a yokeless, Neodymium disc direct magnet system. The connection pins are silver plated.
As with any line contact type stylus, correct VTA/SRA is critical to optimizing performance so a VTA adjustable tonearm is recommended if not mandatory. Compliance is approximately 12x10cm/dyne at 100Hz. Recommended tracking force has a narrow window of 1.7g—1.8, with 1.75 “preferred.” Recommended loading is between 91ohms and 47kOhms determined by listening. VTA is 20 degrees, which Lyra says is achieved with the arm parallel to the record surface. As with other Lyras, the generator is integral to the body as opposed to being a completed mechanism inserted into a body. The result is better mechanical grounding, energy transfer and inherently correct alignment of the generator and body.
You can determine the “mathematically correct” loading according to Carr’s instructions by determining the total capacitance between the Delos and the phono stage. While the ultra low inductance of moving coil cartridges makes capacitive loading far less critical than it is with MM cartridges, there remains a relationship between capacitance, load value, bandwidth and the amplitude of the ultrasonic resonance.
Usually though, a setting of 10X the internal impedance is a good starting point, which is why Lyra species 91 ohms as the low, which is just above 10X the Delos’ 8.2 ohm impedance. According to the instructions if your cable’s capacitance is 100pF per meter, for instance, loading at 390 ohms will suppress the peak to 3dB while 200 ohms will suppress it to 0 at the expense of slightly poorer phase response and reduced dynamics. I went with 500 ohms but listened at 100 ohms as well, which is where I preferred it.
One interesting new design wrinkle here is a new body angle and a “pre-angled” damper system that aligns the coils and magnetic circuit with the application of the proper VTF. Most cartridges, Lyra claims, provide this alignment only when no tracking force is applied."
I dug out my manual for my C-J EF1 phono stage. (btw I run the phono stage into a C-J Premier 17 LS, a very high quality tube preamp I acquired from a good friend 20 years or so ago.) The avail loading is: 200 ohms, 500, 1.9K, 9.6K, and 47K. These are set by dip switches. One sentence I will quote from the manual. "The factory preset 47K load (all switches off) will be best suited to most cartridges."
C-J does not mention MM or MC carts in any of their instructions....go figure.
I am running Audio Quest King Cobra interconnects throughout the entire system chain of equipment. I have no idea how to calculate the mathematical correct loading; and even if I could, it may not be avail in my phono stage. Since my Pre amp and Amp are tube C-J equipment, I'm hoping C-J did all the 'correct engineering' so their equipment runs together in harmony. The way my system is stacked it's a hassle and 1.5 hr job to switch the loading, which requires me to get on a ladder...no fun. For the time being I'll leave it at 47K. If I decide I don't like it, I'll switch to 200 ohms and call it a day. I really don't want to 'play around' with loading. Just find the best setting and leave it alone...Thanks for all the feedback!
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Recommended loading is between 91ohms and 47kOhms determined by listening.
@quincy I love that Lyra states things this way- Jonathon Carr is well aware of how differently phono sections behave when presented with the RFI generated by LOMC cartridges. Normally you'd expect a very specific value for something like that, not something determined by 'listening'. But until more phono preamp designers get the implications of the LOMC cartridge making RFI, about the only way to do will be by 'listening'.
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Well, played many favorite records at 47k for awhile. Didn't like it overall. A little to bright, if that's a good analogy. Switched loading to 200 ohms yesterday. Better. Not much difference from the original 500 ohms I've been running for the last decade. Will leave it at 200 and call it good!
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Well, played many favorite records at 47k for awhile. Didn't like it overall. A little to bright, if that's a good analogy.
@quincy It is. If you experience brightness, IME this is because the phono section really isn't happy with RFI at its input. So loading is really the best thing you can do.
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Yep, your correct!
Thanks to all for the support!
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The lower value 200 ohm vs. 47k ohms means more loading which tends to attenuate higher frequencies (because we hear things in terms of overall balance, attenuating highs can also be perceived as more bass). Another way to attenuate highs is to lower the VTA/SRA (lower the pivot point of the tonearm). This means that, to some extent you can play around with both loading changes and small VTA/SRA changes to find the best combination for achieving the tonal balance that you want. I know this adds to the complications, but, it also may enhance your sweet spot.
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@larryi to add what he said, it is one of the best things about vinyl. On one hand you want some setup to be dead on, cart alignment etc. But, when it comes to final sound there are lots of possibilities between loading, VTA, and VTF (to a degree). All can be tweaked to achieve just about any realm of balance desired.
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reset the loading to 47K, buttoned things up and called the wife in for a listening session. Sure as heck both of us noticed the highs were crisper
This is a common trick for many listeners over 60. Brings back the "airiness" of youth. Do whatever sounds best for you, not others.
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The lower value 200 ohm vs. 47k ohms means more loading which tends to attenuate higher frequencies.
If this were the case it would be easily measured yet I have yet to see this actually documented.
Another way to attenuate highs is to lower the VTA/SRA
This is another case of something widely accepted, easily measured yet completely undocumented.
I want to be clear that I am not doubting there is a change in sound from varying load or changing SRA, I am just suspect about the "change in frequency response" explanation that is widely accepted as the cause.
Peter Moncrief in IAR 5 makes a compelling case with measured confirmation that loading of an MC cartridge does not materially effect the measured frequency response of a MC cartridge. He then goes on to show how loading does measurably change the amount of IMD created from the trackability tones on the Shure TTR103. He then finally proposes that the excess IMD caused by a lightly loaded MC cart is often perceived as high frequency detail that many have grown accustomed to and the "dark" sound of heavily loaded cartridge can be due to a system being tuned for the typical lightly loaded case.
dave
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I suppose I should have preceded my comments with the phrase "I perceive as" because I did not take measurements. In any case, the sound changes, both with loading changes and VTA, and whether or not it is actually added distortion that one might be favoring with a higher VTA and lower loading (higher resistance in parallel), I don't really care; I like what I like. I suspect that a lot of the appeal of vinyl playback IS something added, and perhaps something lost, as compared to the original recorded signal, but, I don't have any sort of religious commitment to authenticity/accuracy. I happen to like, for example, many works of visual arts that don't depict their subjects with the same "accuracy" as high definition photography.
If light loading is entirely added intermodulated distortion and the "real" and "accurate" sound is what you get with high loading, I will take distortion. As an experiment, one could try the loading of a MC with relatively high source impedance (like a Denon 103) with something like a 10 ohm resistor. One would have to compensate for the loss of gain from using such a resistor, but, one will hear quite a difference in sound as compared to a light loading (e.g. 47k); I would not chide anyone for preferring lightly loaded and accuse them of having incorrectly becoming "accustomed " to light loading.
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Dear @intactaudio : You are rigth and what PM IAR 5 posted was confirmed by J.Carr when in other thread on the same issue posted:
" 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. "
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.
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The lower value 200 ohm vs. 47k ohms means more loading which tends to attenuate higher frequencies (because we hear things in terms of overall balance, attenuating highs can also be perceived as more bass).
If light loading is entirely added intermodulated distortion and the "real" and "accurate" sound is what you get with high loading, I will take distortion.
The loading has no effect on the cartridge other than making the cantilever harder to move. You can take any LOMC cartridge and put it on the bench. Using a squarewave generator (at a very low loutput, so as to not damage the cartridge), you can put the cartridge in series with the squarewave and then measure the output. With no resistor in parallel this is an unloaded inductor. What you will see on the oscilloscope is a nice squarewave, looking really quite a lot like the input, neither attenuated or rounded and with no overshoot! This is simply because the inductance of the coil is too tiny to ring at audio frequencies.
So the 'brightness' we often hear is coming from somewhere else!
Putting a resistor in parallel will not affect that. So the resistor is not affecting the bandwidth of the cartridge. But it is interacting directly with the electrical resonance, which is a product of the inductance of the cartridge and the capacitance of the tonearm cable.
As we can see from the page http://www.hagtech.com/loading.html
the peak can be substantial. The reason is something called 'Quality' or simply 'Q'. Inductive coils can be long and narrow, having a low Q value, or short and wide, having a much higher Q value. The higher the Q value the higher the peak and the narrower the band of frequencies it covers. LOMC cartridge have high Q coils in them for lowest mass.
Some preamps don't like having all that RF noise caused by the peak at their input. So they do weird things and one of them is distortion. Loading knocks out the electrical resonance and if the preamp has a problem with the RFI, the brightness along with it.
One would have to compensate for the loss of gain from using such a resistor, but, one will hear quite a difference in sound
This statement is only true if the preamp is sensitive to the RFI at its input. If not, no difference will be heard. Most designers simply don't take the implications of this electrical resonance into account in their phono designs, which is why this loading conversation persists.
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Sort of makes a good argument for transimpedance as the initial stage of a phono preamp . . .
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Ralph
The loading has no effect on the cartridge other than making the cantilever harder to move.
Isn't that essentially suggesting that compliance has no effect on the sound of a cartridge?
did you ever get a chance to look at the copy of IAR #5 I sent you? I find it entirely plausible that making the cantilever easier / harder to move would have a sonic impact on the sound of a cartridge. Add to this that this effect will be dynamic based on the musical content and things get interesting. If you trust the measurements made by Moncrief, he clearly shows a reduction of IMD and it isn't a huge leap of faith to believe that the degree of measured IMD change he shows would have an audible result.
dave
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@rauliruegas
What Jcarr and in parallel Ralph are saying is completely different than what is presented by moncrief. They all agree that loading has no effect on the measured frequency response of a cartridge but any similarities end there. Ralph and Jcarr suggest the unloaded "harshness" is caused by the MC cartridge inductance resonating with cable/input capacitance resulting in input overload of a phono stage that is not "RFI stable". Moncrief suggests (and shows) that for MC carts, IMD distortion levels are directly related to applied cartridge load.
dave
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What it boils down to is that loading matters to the sound, but there is some disagreement here as to why it matters and the cause of the sonic difference. One position is that low loading is preferred because it CAUSES distortion that is perceived as high frequency information and people have grown accustomed to, and prefer, the distortion. Another point made here is that RFI overloads some electronics causing distortion which is ameliorated by loading that damps RFI. I suppose these are not contradictory statements and they may both account for some preferring low loading and others preferring more loading. Jonathan Carr (Lyra cartridge designer/builder) says that low lading is preferable, because it preserves the high frequency response, which is one of the things people pay big bucks to get from MC cartridges, but, that higher loading might be necessary to kill RFI that can overload some gear (Atmasphere's position, and I tend to agree).
As to Atmasphere's response to my statements about the sonic effects of loading-- that loading has no effect on the cartridge, except to make the cantilever harder to move-- I was merely stating that the effects of loading changes can be heard, not that loading physically affects the cartridge. There are cartridge experts that say that the back EMF changes from loading are so negligible that the effect on movement of the cantilever is mostly theoretical an not a practical reality.
Perhaps my statement about having to compensate for difference in loudness where a low value resistor is used (high loading) was misconstrued. I was merely pointing out that when making a comparison, to be fair, one might have to increase the volume a bit for the high load scenario to compensate for the voltage drop across the load resistor; with a high value resistor (low load), that drop is less significant
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Isn't that essentially suggesting that compliance has no effect on the sound of a I cartridge?
I need to clarify: It has no effect on the output of the coil. It certainly has an effect on the cantilever, and if you look at my prior posts you'll see that I suggest this may affect its ability to trace higher frequencies.
did you ever get a chance to look at the copy of IAR #5 I sent you? I find it entirely plausible that making the cantilever easier / harder to move would have a sonic impact on the sound of a cartridge.
I did- thanks- and agree, since this likely has an effect on how it tracks. IMO what Moncrief did not show is where the IMD was coming from; IMO it is caused by the phono section rather than the cartridge directly.
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Dear @intactaudio : This is part of the J,Carr w.papers ( I never seen any from atmasphere. ) that I'm sure you are aware of it:
- Kleos electrical model (9uH, 5.4ohm, 8pF)
- Lyra Phono Pipe Very Low Capacitance tonearm-to-phonostage cable 120cm actual measurements (0.75uH, 0.325ohm, 32pF)
What these tell me (among other things) is that, all else being equal, changing just the interconnecting cable (each of which has a different capacitance characteristic), changes the optimal resistive load; and if you can afford to bring up that peak in the MHz to something <10dB then you can bring up resistive loading to about 500-1K ohms even with a highly-capacitive cable; and finally, you are not really affecting the audible high frequencies with any resistive load shown. "
Yes he said too that a phono stage could be overloaded by the inductance, load impedance and cable capacitance if the designer does not took in count this issue and when that happens appears as IMD. Today SS designs comes with really high overload/headroom margin/level.
You said:
" Moncrief suggests (and shows) that for MC carts, IMD distortion levels are directly related to applied cartridge load. "
but atmasphere that has that IAR 5 posted:
" did not show is where the IMD was coming from..."
So, if PM did not shows from where comes the IMD only JC is rigth?
Because exist a big difference in both assertions what you said that PM showed means that always appears the IMD when what JC said is that the IMD sometimes could appears when the phono unit design was not designed tooking in count that " issue ".
I think that you need re-read the PM w.papers or pasted here for all we can learn and most important to answer my question to you.
R.
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So, if PM did not shows from where comes the IMD only JC is rigth?
I would say no since the two loadings PM shows for his IMD are 5Ω and 100Ω both of which will surely damp any possible LC resonance which would then eliminate the whole RFI aspect. I will note that the cartridge used has a 30Ω internal impedance so the 5Ω and 100Ω values are odd but that is secondary to demonstrating the effect.
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Dear @intactaudio : Re-reading several posts here and in other forum about the loading issue I tend to agree with you. Please let me explain:
first JC works graphs here were not to prove nothing about IMD or frequency changes because MC loading.
That's why he posted that " FR changes is bogus " when he posted this to a forum member who asked about the FR effects of cartridge loading: brigth vs dark sound. Doing his thread answer ( JC ) made a comment about IMD but was only a comment to re-afirm/confirm that exist no FR changes because loading. A time comment and nothing more than that.
PM confirmed no FR chnages with cartridge loading and all these is the only true about cartridge loading and FR.
The JC advise is the lower cable capacitance the better.
@larryi pointed out:
" One position is that low loading is preferred because it CAUSES distortion that is perceived as high frequency information and people have grown accustomed to, and prefer, the distortion. "
According what you said PM posted:
" finally proposes that the excess IMD caused by a lightly loaded MC cart is often perceived as high frequency detail that many have grown accustomed to and the "dark" sound of heavily loaded cartridge can be due to a system being tuned for the typical lightly loaded case. "
@hagtech posted with no other significant comment:
"
reset the loading to 47K, buttoned things up and called the wife in for a listening session. Sure as heck both of us noticed the highs were crisper "
All those post coincide in that specific regards.
Now, I can remember that over 30 years now I almost always recomended to load highly the MC cartridges at around 100 ohms and doing what larry posted: move the volumen position to recover the SPL and with this simple " even SPL " the dark sound just gones and the sound will shines with lower distortion levels that at 20k-47k.
Today with your help of those PM works and the other gentlemans help I confirm that over the years my take about those 100 ohms loading is just rigth and as a fact that's the load impedance that I used and use with dozens of LOMC cartridges that I owned and own in my active high gain phonolinepreamp and when I'm using a SUT in my unit I set up the MM load at 100k. Everything works excellent.
Thank's to you all to share a critical information for me. Good !
R.
R.
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Dear friends @intactaudio : I made an extensive search looking for documented/measured information about the JC comment on IMD and looking for too if JC mentioned a second time that issue and he never did it, at least I can't find out.
Btw, here information from experts, first by @hagtech :
"" As mentioned earlier, the peaking is best damped by lowering the load resistance. This is why MC cartridge manufacturers often request loading of about 100 ohms. The next plot shows the 5mH 10 ohm cartridge loaded with 200pF and a variable resistance. ..................... Most MC cartridges have less inductance than this example (chosen to highlight the issue), and so the typical loading value of 100 ohms is usually quite reasonable. "
Next comes by the designer/manufacturer of SUTs as intactaudio:
" Most modern moving coil cartridges have a source impedance of about 10 ohms and the “load impedance ten times the source impedance” rule suggests 100 ohms is a good choice for load impedance ...... This is well in line with the recommendations from many cartridge manufacturers. Anything above 100 ohms should be equally suitable.
Does the cartridge's tonal balance change with load impedance? It certainly does if the cartridge is a moving magnet type, but low output moving coil cartridges are much less sensitive to changes in the load impedance. Users sometimes claim that higher load impedances produce a brighter sound than lower ones, but cartridge manufacturers tend be non-specific about recommended load impedances, often recommending a wide range or simply anything above a minimum impedance.
The recommendation of Rothwell Audio Products is in line with Ortofon, Audio Technica and most other cartridge manufacturers - that 100 ohms is a good value for most cartridges, and that the exact value is not critical as long as it is well above the cartridge's source impedance.
One thing is certain, and that is that the load impedance should not be equal to the cartridge's source impedance. That would produce a 6dB loss of signal (when there's often only a few hundred microvolts to start with) and seriously compromise the signal-to-noise ratio. "
R.
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I would say no since the two loadings PM shows for his IMD are 5Ω and 100Ω both of which will surely damp any possible LC resonance which would then eliminate the whole RFI aspect.
@intactaudio FWIW 5 Ohms as a load is so low that most cartridges will produce measurably less output whereas at 100 Ohms the output would hardly be affected. At least this is true of any LOMC cartridge I've measured (a cartridge of 30 Ohms would be affected by both). Knowing that, when I saw the 5 Ohm value in Moncreif's measurements I was forced to take his conclusions with a grain of salt. I think he would have produced better science with 75 Ohms as his lower limit.
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I do not think the value of the loads chosen invalidates the test. Sure it may over-exaggerate things in the traditional sense in the voltage realm. When you consider the proliferation of "current mode" phono inputs in vogue the 5Ω value isn't so strange.
dave
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I don't usually get too caught up in the Interface methodz being discussed in the descriptions offered.
Using the Manufacturers recommendations, has been quite successful for my own purposes.
I have a selection of Cables, as well as few SUT's and cam also have the use of Head Amp's
I will swap different configurations to see what develops in the SQ.
I also have a Phon' with a methon to control input capacitance, input impedance and adjust gain.
I will use this to learn if a chosen configuration is able to be improved upon.
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Dear @intactaudio : "
and 100Ω values are odd but that is secondary to demonstrating the effect. "
and something important is that PM is the only gentleman that showed/measured in that regards,
The critic made by atmasphere is useless and for any one is easy to post that kind negative comments. Could be better to prove with measures that PM is wrong, this is the way to do it but obviously till that happens PM it's not wrong and in this regards a congratulations to him is the least we can do for.
Again, thank's for your PM information that trully and finally puts the " ligth " we all need it about.
R.
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When you consider the proliferation of "current mode" phono inputs in vogue the 5Ω value isn't so strange.
Transimpedance phono sections have the cartridge driving the 'virtual ground' of an opamp circuit. That's quite a bit different from driving an actual short (0 Ohms)! For example, if the cartridge isn't present, the virtual ground does not exist. They really aren't an example in this context.
Try placing a 5 Ohm resistor across the output of any LOMC cartridge and see what happens 😁
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I didn’t mention a dead short and was only referring to the two terminal impedance the coil of a cartridge sees. Any reference to ground be it real or virtual does not factor into the load seen by the coils. Surely there has to be an actual input impedance for a current amp and it has to be low otherwise the coils will not generate any current to amplify. I am not trying to get into an in depth analysis of how various transimpedance amplifiers work but address the general first order behavior of the system and believe that a cartridge operating into a ideal voltage amp behaves differently than the same cartridge into an ideal current amplifier primarily due to the fact that the loads are at opposite ends of the spectrum.
Try placing a 5 Ohm resistor across the output of any LOMC cartridge and see what happens 😁
that depends on what load the input of the following stage gives.
If it is a voltage amplifier with 47kΩ, a 30Ω cartridge loaded by 5Ω it will be 17dB down. When you replace that 30Ω cart with a 2Ω cart the output will only be down 3dB. If it is a current amplifier with a 1Ω input impedance a 5Ω parallel load will lower the current into the 1Ω input node by1.6dB with both the 2Ω and the 30Ω cartridge. The absolute currents will be different for the 2Ω and 30Ω carts but the relationship of how the 5Ω load affects a 1Ω input impedance stays the same.
dave
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I didn’t mention a dead short and was only referring to the two terminal impedance the coil of a cartridge sees. Any reference to ground be it real or virtual does not factor into the load seen by the coils. Surely there has to be an actual input impedance for a current amp and it has to be low otherwise the coils will not generate any current to amplify.
Do you see how this above does not jive with this:
that depends on what load the input of the following stage gives.
If it is a voltage amplifier with 47kΩ, a 30Ω cartridge loaded by 5Ω it will be 17dB down. When you replace that 30Ω cart with a 2Ω cart the output will only be down 3dB. If it is a current amplifier with a 1Ω input impedance a 5Ω parallel load will lower the current into the 1Ω input node by1.6dB with both the 2Ω and the 30Ω cartridge. The absolute currents will be different for the 2Ω and 30Ω carts but the relationship of how the 5Ω load affects a 1Ω input impedance stays the same.
Transimpedance phono sections have a dynamic load whereas a resistor is a static load. This is because the so-called 'virtual ground' (which will be 0 Ohms) occurs where the feedback resistor of an opamp meets the input resistance, which in this case will the cartridge itself.
At any rate, Moncreif threw off his numbers by using a 5 Ohm load, since that is not only not a real-world value that no-one would ever use, but is also one that would significantly decrease the output of any LOMC cartridge to the point that its output would be unusable (which is why its not real world...). Keep in mind that transimpedance phono sections didn't exist back then. As I mentioned previously, if he really wanted to make his point valid he needed to show the results using real world loads that are actually in use.
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That laST POST IS PART OF THE WHOLE REGARDS STUPIDITY COMING FROM THE SAME PERSON, COMING FOR HIS FRUSTRATION .
@intactaudio audio " falls " in that person game ( because intactaudio in good faith gentleman unknow that person game. ) that when he can't win then he follows been argumentative and goes " around and around " with different issues than the one under discussion ( exactly like here. ) makind a way deviation from the main subject.
I followed his " game " when he already bbeated and I did it for many years till I learned.
That's why JC just does not follows that stupid game and never suported him with the IMD issue discussed for years.
Please look to what stupid levels goes his stupidity:
""" At any rate, Moncreif threw off his numbers by using a 5 Ohm load, since that is not only not a........., if he really wanted to make his point valid he needed to show the results using real world loads that are actually in use. "
Certainly it's not PM who should do that because PM shows at 100 ohms too but more important : that stupid man not only does not shows nothing/measures to prove his point but now he ask that the gentleman that measured and proved that the IMD is developed by the cartridge loading effect still makes more measures: GO FIGURE ! ! !
Yes, in our world exist any kind of stupidity we could think.
R.
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Now, now... let's try and keep it civil. I've enjoyed the discussion this far and am impressed by many members knowledge base. Which is very helpful to the lion's share of members!
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Ralph,
The two statements you quoted from me seem to align well with each other and I was unaware that there was a different versions of ohms law for static vs dynamic loads
At any rate, Moncreif threw off his numbers by using a 5 Ohm load
I agree it is an interesting choice but his measured results clearly show signal and if if anything a lower noise floor so I fail to see where the issue is or how it invalidates his results.
dave
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The two statements you quoted from me seem to align well with each other and I was unaware that there was a different versions of ohms law for static vs dynamic loads
At any rate, Moncreif threw off his numbers by using a 5 Ohm load
I agree it is an interesting choice but his measured results clearly show signal and if if anything a lower noise floor so I fail to see where the issue is or how it invalidates his results.
In the case of a transimpedance input, feedback is applied to the output of the cartridge. Its a fair amount of feedback too- the more output the cartridge has the more feedback. That is quite a bit different than a simple resistor- you can’t equate a virtual ground with a static resistance- for one thing, you need an opamp to even create a virtual ground.
Ohm’s Law certainly is in play (how could it not be), but the issue here is that while a cartridge has its output at a virtual ground, that is significantly different from having the cartridge drive 0 Ohms (IOW, if it were actually tied to ground). In the case of the former, the actual input impedance is dynamic and isn’t actually 0 Ohms, so amplification can occur because a signal is present. In the case of the latter, the load is actually a short and because the signal is shorted out, no amplification can occur.
’Virtual’ means ’almost or nearly as described, but not completely or according to strict definition.’ If the 0 Ohms of a virtual ground is conflated with the 0 Ohms of actual ground, confusion is the direct result.
Real ground is when a terminal is connected physically to the ground or earth, whereas virtual ground is a concept used in opamps in which a node is assumed to have the potential that of the ground terminal.
I say Peter threw off his numbers because he chose a value that no-one would ever use (and a static value at that, no opamp involved, so the load was causing the output of the cartridge to change in a significant way, whereas real-world loads have negligible effect) since its a reasonable expectation that if you are going to use a load on a cartridge, you’d likely start with one that is 10X the source impedance of the cartridge.
I can see using static values lower than that, but not one that’s actually lower than the the source impedance! Barring a good explanation for that, when I read that in his article I found I simply had to take his results in abeyance. I’d have to read the article again (Google defeated my attempts to locate it just now), but IIRC he had some variables left uncontrolled that I felt at the time might affect his results.
One way around this is to ignore that transimpedance inputs exist and simply focus on what happens to the output of any source when the load is a fraction of that of the source. That’s really what I’m getting at here, if Peter was actually suggesting that we use such loads both back then and now the extra gain needed would be impractical.
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Dear friends: Looking to the PM charts that @intactaudio shared with us yesterday I took in count that ( for my self. ) I can measure it too due ( as I posted several times in this forum. ) that I own around 20+ different vintage comercial test LPs from: CBS, Shure, JVC, Stereo Review, HiFI, Vanguard, B&K, Ortofon, Audio Technica, etc. etc.
Through them I have 4 tracks IMD dedicated and rigth now I'm talking with some of my audio friends looking for the ritgh phono stage that permits in easy way changes in the cartridge loading because in my unit I can do it unsoldering/soldering resistors . As I said I will do for my self satisfaction and with withness of the gentleman that will share his phono stage for 3-4 hours any day in the afternoon.
So " stupid " I'm that having a solution I did not see way before.
R.
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Dear friends: Looking to almost all my vintage LP test recordings I found out that I have some even sealed as one from Micro-Acoustics and the Ortofon serial 003 that yesterday opened and listen to it.
It's not a test tones and the like but the lovely tracks are MUSIC, this LP is an Ortofon collaboration with the label Opus 3 that in the past ( too ) made 3-4 test LPs.
Well, first than all this Ortofon LP is really good centered with no waves you can detect and even that's a vintage recording not only is a great recording but the LP recorded surface is dead silent, even the band that separates the tracks is dead silent.
If you can find out buy it, it's a good investment for you and your room/system set up.
R.
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