This has been covered in other threads.
However, in a nutshell there is a simple reason that you see variable results. It has to do with how sensitive the phono section is to Radio Frequency Interference (RFI).
Now its a fact that at almost any loading value you can put on a LOMC, you will not affect the response of the unit at audio frequencies. But when you install the loading resistor (often quite low in the case of LOMC) you can hear a change.
This is because the cartridge has an inductance, the the interconnect cable has a capacitance. Together they form a tuned circuit at ultrasonic (RF) frequencies. The action of the the cartridge playing provides the energy- and so the tuned circuit thus injects RFI directly into the phono input.
Now if the phono section is stable with the presence of RFI at its input, you will not hear a lot of effect with loading the cartridge. But if RFI is able to mess with your phono section, then you will hear big differences. The effect of a resistance is that it lowers the energy of the tuned circuit. When that energy is low enough, the perception will be that you found the sweet spot.
Mind you, this is the 'nutshell' version of this explanation. But it does explain why you will see difference of opinion here.
The bottom line: if you hear big differences with loading, your phono section is sensitive to RFI. |
I know but apparently way over your head. You should just give up this line of work. |
Here is a useful reference for those of you who want to get some facts on the loading of a MC cartridge.
http://www.extremephono.com/Loading.htm |
Lowering the numerical value (increasing the load) will muddy or blur the presentation. |
I suggest that people read a bit more, like Atmasphere's last post on this thread, and this reply by Jonathan Carr in a thread from last year. The thread is regarding the XV-1s but the post is more general regarding MC loading. Also followed by another post by Atmasphere. jcarr on mc loading |
Dan_ed: I have read the references you suggested,thanks. Is this different from the analysis of a critically damped tuned/ resonant circuit? I would imagine that the "loss" of energy in the sound with the reduction of the 47K load is the reduction of the resonant peak within the audio band around 10 -15Khz and quite common in MC cartridges. Surely a more accurate reproduction would be without this peak present? The earlier reference I posted shows the result of this in a real world cartridge. |
Stops, sounds to me like you have a pretty good understanding of what is going on here. We are indeed talking about a tuned resonant circuit, and how to damp its behavior. |
Stops, yes it is a resonant circuit, no news there. There was something in the information from the link you posted that didn't quite sit well with me, but looking back now I can't think of what it was. NOthing earth shattering. I think it was something simple, like pointing out that we are really tuning more for upstream cables and circuits rather than just the generator itself. I know many people (not saying you) get agitated by cart specs that only say ">30 ohms" and not give a specific value. Hopefully, folks understand the why after reading those posts. |
I think, there is also some useful information at the website from Stan Klyne (www.klyne.com), he found the solution to do it right. |
It is refreshing to hear from sane personnel. I appreciate all the comments and suggestions. I will reiterate a point I made much earlier and that is -I found much greater differences in the sound from the VTA and playing weight than I did from adjusting the load resistance of the cartridge. So I suggest that adjustment be done first using a playing weight in the middle of the spec as per the manufacturer and a tone arm that is level.
Intuitively I would expect a critically damped cartridge to handle complex orchestral pieces better (faster recovery?). I do find that I can hear much more of the individual instruments in a complex passage with an optimum load. |
It’s an old thread, but this is exactly what i’m doing now by loading my Miyabi MCA at 47k Ohm (JLTi phono stage) and this is by far the best setting for this (low impedance / low output) MC cartridge.
This is not the only one LOMC cartridge in my collection that just fantastic with 47k loading on my preamps (different preams).
How many people on here prefer 47k for MC ? |
I tried on 3 or 4 different lomc carts but in all honesty my best results by ear were between 220 and 470. Anything higher
just dulled off the presentation as a musical whole. This was with carts ranging from .24mv to .4mv, maybe really lomc like .1mv or less may show more change?
Btw, using same phono stage as yourself Chakster. If you are still using the GoldNote that is. |
Most audiophiles have a Pavlovian response to the question of how to load an MC cartridge. They've been told for so long and from so many sources to use a low value resistor (typically 100R or some resistance that is about 10X the internal resistance of the cartridge) that they cannot accept another idea. My money is with Ralph and JC and any other of several knowledgeable gurus. A few years ago, I inadvertently loaded one of my LOMCs at 47K ohms. The experience was a revelation, and I have never looked back. There's nothing wrong with the typical approach. Nor is there anything wrong with 47K ohms, and theory says there is a lot that is good about the idea.
Unlike Uberwaltz's testimony above, I invariably find that 47K gives a slightly more open, extended sense of treble, compared to 100R. He doesn't say what cartridges he uses. In my case, it's ZYX Universe (0.24mV output), Koetsu Urushi, Ortofon MC2000, etc. But, as Ralph says, the phono stage itself has most to do with the outcome.
|
Lewm.
The 4 carts I tried all with same phono stage.
Lyra Dorian
ZYx RS50
Scheu SL
Ortofon Cadenza Black.
Out of them all the ZYX sounded best at 470 and the rest at 220.
Was and still am open to trying any and all loading but that was results for myself.
Obviously to my ears in my system etc etc. |
Long time ago when i bought my first hi-fi phono stage i didn’t know about loading. There was just one switch between mm and mc, later i realized it was just a gain switch, but the load was 47k for both (low and high output cartridges). Guess what phono stage it was?
It was $500 Grado PH-10 phono stage. The reason for no optional loading was obvious (all Grado carts are MI). I was using MC with that phono stage and it was just fine for LOMC.
My secong phono stage was much more expensive (about $2k), but also with no optional loading on MC input, because two SUTs inside the phono stage :) This is still the best phono stage (WLM Phonata ref.) when i need the deepest bass, nothing can beat it in low register for some reason.
Using JLTi at the moment i like 47k for MC, not for all of them, but for most of them (low impedance MC). I can use whatever load resistors with JLTi, i’m using low value resistors only if the cartridge is too bright, but it rarely happens. For open sound 47k Ohm is the best.
Regarding the Uber’s question i think the loading from 100 Ohm to 47k Ohm on my Gold Note phono stage is irrelevant for my FR-7fz. Only when i’m using lower value (for experiment) the sound became rolled off and not interesting in my system. Anything from 100 Ohm to 47k Ohm is good, i can’t detect a big difference with this particular FR-7fz cartridge. However, ZYX CPP-1 headamp does some magic with the same cart, it’s better with ZyX headamp in between FR-7fz and Gold Note phono stage (in MM mode).
Ortofon MC2000 directly connected to Gold Note was fine loaded at 47k or lower.
I think 47k Ohm is pretty much universal for most of my LOMC
|
Very interested indeed.
I had read a lot about 47k loading for lomc and was real fired up for it to work, so you could say I even had some expectation bias for it to sound good.
But after numerous listening sessions with,numerous carts ( and as you know the change on Goldnote is instant so real easy to tell, no memory thing) it just did not cut it for me.
Maybe in my case it is the sum of everything else, cables etc.
Right now running Nagaoka MP150 so not going to experiment again anytime soon. But I tried enough to say just in my system, my carts, my ears it was not optimal loaded at 47k. |
Well, as Ralph explained many times it's all about the phono stage.
And probably a cartridge impedance
P.S. sadly you can't try your nagaoka MM with 100k ohm |
Correct Chakster but as we have the same phono stage and get differing results it has to be something else.
My carts, my total system or my ears! LOL.
|
I was thinking last night that results might to some degree depend upon the input capacitance of the first gain stage in your phono section. Both of my phono stages use a cascode input. In a cascode, the gain element that receives the incoming signal is isolated from the anode of a completely discreet separate gain element via a direct connection between the anode of the input tube and the cathode of a second tube. therefore there is very little or none of what is called Miller capacitance. (Both tubes and transistors exhibit the phenomenon of developing a capacitance between the anode of a tube and the grid. Also between cathode and grid to a lesser degree..) And a transistor has analogous nodes. So if you are using a phono stage with a 12AX7 input tube, for example, The miller capacitance can be quite high, because it is in part a function of the mu which for a 12AX7 is very high. Cartridges connected to the grid of a 12AX7 in a common cathode topology would possibly do better with lower value load resistors. All of the above applies to triodes. Not many tube phono stages use pentodes anyway. Of course, you should keep the cable capacitance as low as possible also. |
Dear @lewm : """
loaded one of my LOMCs at 47K ohms. The experience was a revelation, and I have never looked back. ""
That means that you are loading your Essential 3160 at 47K?
R. |
|
