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Cartridge loading

Presently I am using a ZU/Denon DL103 mc cartridge with ZU Audio's highest tolerances.  I had this cartridge mounted on my VPI Prime and after going through all the various loading combinations, I settled on 200 ohms.  I was always satisfied with my choice of setting.  I no longer have the Prime and now use the Technics SL1200G turntable.  After having the same cartridge mounted and aligned by the dealer, I inserted it into my system and enjoyed the sound immensely, never touching the 200 ohm setting.

Yesterday I was listening to vinyl most of the day and for some reason I found the sound to be better than ever, mostly in the treble area.  The highs had shimmer when needed and I had played the same records many times before on the Prime and they never sounded as good as they did yesterday.  Just for the heck of it, I checked the cartridge loading and found it was now set at 1000 ohms.  As I said, when I put the Technics into the system, I never bothered changing the loading which was at 200 ohms as it was the same cartridge, just a different turntable.

I believe I know what happened, when I last used the tone controls on my McIntosh preamp, (you have to shuffle through a menu) I must have inadvertently put the cartridge loading at 1000 ohms.  It truly sounds fantastic, better than I ever thought possible.  The Bass is still very deep and taut, midrange is the same but the treble, oh my, so much better.  Now the million dollar question is why should it now sound better at 1000 ohms, when it sounded great before at 200 ohms?  Can the tonearm on the Technics have an effect on cartridge loading?  I always thought it was all dependent on the preamp, amp and speakers.  What am I missing here?  I am very curious to know.  The specs for my cartridge say greater than 50 ohms for loading.

Thanks
128x128stereo5
catcher10's avatar
catcher10
77 posts
 
What @atmasphere writes is very much what is causing your change in sound character. Loading at the phono stage and not at the cartridge is what you should be looking for. Also what phono cable are you using and do you know its capacitance? A very low cap cable should be what you use along with a higher resistive setting at the phono stage (like 1000 ohms) then you allow the cantilever to move freely in the groove, rather than a low resistive setting might stiffen the cantilever and make the cart work more.
If I load my Delos at 100 ohms the sound is closed, restrictive and bland, I load at 475 ohms and the sound becomes very dynamic and very high resolution.
stereo5's avatar
stereo5 OP
6,254 posts
 
I am using the VPI phono cable.
whoopycat
165 posts
 
The Zu Denon is very much a "salt to taste" kind of cartridge when it comes to loading.  When I used one it could indeed sound quite different when using 100/200/300/500/1000 ohms.  And Zu will tell you there is no wrong answer here, just use what sounds best to you.
intactaudio
293 posts
 
There is an interesting article in IAR #5 by Peter Moncrief titled "Audio Fallacies Exposed  Low Impedance Loads for MC Cartridges" about loading and he proposes that loading down a cartridge helps it keep better contact with the grove. 

Moncrief attacks the general held belief that 'loading a MC cartridge damps a HF ringing and the "dull sound" from too great of a load is simply an overdamped response'  He then goes on to show swept frequency responses of MC cartridges under varying loads showing minimal change in the frequency response.   

He then goes on to point out that loading down a cartridge has a sincere effect on the side bands created from 400hz + 4Khz intermod test track.  He shows plots of different load situations and it can clearly be seen that the more the MC cartridge is loaded the more the side bands that are created are reduced.  Being the Skeptic that I am I repeated his tests and confirmed his results.

dave
atmasphere's avatar
atmasphere
11,577 posts
 
The Zu Denon is very much a "salt to taste" kind of cartridge when it comes to loading. When I used one it could indeed sound quite different when using 100/200/300/500/1000 ohms. And Zu will tell you there is no wrong answer here, just use what sounds best to you
Again: loading has no effect on the sound of a **low output** cartridge- it has everything to do with the stability of the phono preamp.

@intactaudio While I agree generally with Peter in this regard, I am suspect of the idea that loading causes the cartridge to track better in all cases. I have seen this where the cartridge was otherwise incompatible with a tone arm; a good example is a Grado in a Graham 2.0. The loading prevents the 'Grado dance' that can otherwise occur especially in lead-in grooves. However that is all about tone arm compatibility, and as I mentioned earlier, when you load the cartridge it stiffens the cantilever. So you will get different results in different tone arms! Peter wasn't being entirely scientific in this regard as his data was limited to one tone arm/cartridge combination.

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