Cartridge Loading.....Part II


I read last night the below noted discussion with great interest.  It's a long post but worth the effort and I found it interesting.

It started me thinking about the amount of loading on my moving coil cartridges.  Years ago I purchased my first MC Cart, a very nice Benz Micro Glider, medium output of 0.5 mV as I recall.  At that time I inquired about loading here on Audiogon.  I was convinced, via discussion, by another member, that 300 Ohms was the magic number, so I thought.

Time moved onward and my second MC Cart is currently a Lyra Delos, again medium output 0.6mV.  Both carts had Boron cantilevers', 6 nines oxygen free copper coils and line contact diamond stylis.  When I set up the Delos I did not change or even consider 'loading' changes.  That was a grand mistake.....

Well, thanks to this specific thread I started to second guess myself . (you can do this when retired and more time is on your hands....)

My take from this recent thread is as follows.  Load at 100 Ohms or at 47K Ohms with a quality MC cartridge.  I opened up my Conrad Johnson EF1 Phono Stage this afternoon.  Found it set at 500 Ohms loading.  100 Ohms is not an available setting.  Damn...All these years I've been running the wrong loading, and on two carts, back to back...  I don't recall why I set the loading at 500 Ohms.  Faulty logic.

I 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 and more 'apparent' than in the recent past.  Not a huge difference, but yes, a difference..  Hard lesson learned!

So, you smarter folks on this site might banter amongst yourselves, but in reality there are those of us, behind the curtains, reading and listening!  I just wish I hadn't wasted all those years listening to the incorrect load setting!

Ending with a sincere thank you very much!!

Lou

 

quincy

Sort of makes a good argument for transimpedance as the initial stage of a phono preamp . . .

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

@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

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  

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.