Cartridge Loading.....Part II

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.

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.

 

 

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.

 

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.