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  3. 176314-2065

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
atmasphere's avatar
atmasphere
11,793 posts
 

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.

intactaudio
300 posts
 

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

pindac's avatar
pindac
2,864 posts
 

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. 

Ag insider logo xs@2x
rauliruegas
13,051 posts
 

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.

 

 

 

atmasphere's avatar
atmasphere
11,793 posts
 

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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