Cartridge loading explained

the thin end of the wedge
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bauzace50
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Post by bauzace50 » 26 Jun 2008 19:28

Werner,
to clear up one detail. Some Ortofon cartridges (the VMS series) WERE of the Moving Iron principle, just the same as Grados, ADC, B&O, and others.
But the 2M are of the Moving Magnet variety, the same as their predecessors, the Super OM series.
In any case, this does not detract from the discussion, which is about resistance and inductance, which has been illustrated for these units.
Regards, bauzace50

Werner
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Post by Werner » 27 Jun 2008 07:53

You sure?

When I had an OM20, ages ago, I could clearly see the moving iron
bit in the stylus assembly.

Werner

bauzace50
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Post by bauzace50 » 27 Jun 2008 09:26

Hi Werner,
yes, what you saw was the little magnet at the end of the cantilever. Quite a small rod, which is plainly visible from the rear.
In contrast, moving irons are usually a small tube (or sleeve) at the same spot (ADC XLM, Stanton 680 series) Other MIs use another shape, such as a disc for Grado, and a microcross for B&O, Empire 1000 ZE uses a micro cup, etc.)
What used to be an advantage due to the lower moving mass of the "iron element", seems to have been circumvented by a new breed of smaller and more powerful magnets.
Regards,
bauzace50

LeeS
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Post by LeeS » 26 Jul 2008 20:30

TheChairGuy wrote:the only thing missing is step-ups for low output devices.

btw, I asked in transformer could be fit inside and was told that there was no room for the cans in the fairly slimline Advent casework.

It sits only approximately 3.5" tall
Try the Lundahl LL9206 trafos. They are the size of matchboxes. About 1" x 2". They should fit inside and they are relatively cheap for their excellent performance. Just a thought.

Cheers

carlosfm
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Post by carlosfm » 28 Jul 2008 15:08

andyr wrote:
carlosfm wrote: Even then there are some variations, like semi-balanced (two inner wires and shield, connecting the shield on one side), but these are more capacitive than normal coax.
Hi carlos,

Why do you say that a semi-balanced (2 inner wires plus a shield, connected on one end) cable is more capacitative than normal coax?

Which capacitance are you measuring:
* between the 'hot' and 'ground' inner signal wires?
OR
* between the 'hot' wire and the shield?

Regards,

Andy
Hi Andy,

I don't know why, but I don't receive e-mail notifications from this forum. I didn't know that this thread went on and on! :shock:

I meant the capacitance between the 'hot' and ground. That is, the two inner wires.
The shield in a semi-balanced configuration is only connected to one side of the cable (usually the sending side).

carlosfm
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Post by carlosfm » 28 Jul 2008 15:26

To complicate matters even more, this electrical analysis assumes that this device has a frequency response that is modeled solely on these electrical specs, and that is not the case. There are many other mechanical factors that determine the response. That is why Van Alstine got it wrong, and that is why it would be a mistake to rely solely on electrical analysis.
Of course, you are right.
Simmulations based on the electrical specs just gives you a starting point for the values to use. It can give you what you need right away, but in some cases you have to tune it by ear (which you will always do, anyway).
Besides what Werner says (and he has a point), my calculated values for a Shure M97HE have always produced the best sonic results. I think the M97XE has an inferior stylus, and anyway those graphs that Werner has posted were taken with an incorrect loading of 47K - I insist, this produces huge treble losses with most Shures (and certainly the M97) - but not all.

Btw I now have a matched, hand selected dual linear pot across the inputs of my preamp. It gives much more choices than no matter how many switched resistors you may have. 8)

carlosfm
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Post by carlosfm » 29 Jul 2008 01:07

Hi Carlos,
Good to hear from you again. Thank you for this wonderful thread. You've opened a lot of eyes, or ears.
Thanks for your kind words.
To clarify the graphs I have posted, they were just made to prove my point and better explain what happens with cartridge loading.
Those values must not be seen as ideal. The best sound may be achieved with slightly lower values, in some cases, or slightly higher, in other cases.
Even the quality of the stylus and high frequency tracking may make you use slightly different resistor values.
The point I wanted to make was that MM cartridges also need proper loading (which is very far off the "standard" 47K // hundreds of pF capacitance), being that loading mostly resistive and keeping capacitance to a minimum.

If I have convinced some that have read this thread to experiment with cartridge loading, then I am satisfied.
More than 53,000 views... amazing.

Btw, a cartridge, be it MC or MM (and variants) is not fully setup untill it is properly loaded. And I can say the same for cartridge reviews. :mrgreen:

Alec124c41
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Post by Alec124c41 » 29 Jul 2008 06:45

carlosfm wrote:Btw, a cartridge, be it MC or MM (and variants) is not fully setup untill it is properly loaded. And I can say the same for cartridge reviews. :mrgreen:
Don't forget the reviewer!

Alec

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Post by carlosfm » 30 Jul 2008 11:41

Hi ,

After posting those graphs, I have made some listening tests with my old Shure M97HE Era IV and indeed I have also arrived to 60K or 62k (don't remember exactly, didn't take note).
As the stylus is getting old, I don't use it, but I know what you mean. I like the Shures but I too receive comments that they are boring and lifeless - we know better than that - they aren't.
A friend from Germany has reported back that his Shure V15 (I think it was the III) sounds best with 62K loading.
Don't be surprized that Shure recommends 47K loading because that's what most other manufacturers do.
Most of the times it is way off the ideal, but if you look from the perspective of the (uninformed) user / buyer, he/she will only buy a cartridge that is specified to be used for 47K, which is the input impedance of his/her MM preamp, and most of them.
Although, if you read between the lines and the small letters, some Shure booklets say that the cartridge can be used with a loading of up to 100K without noticeable effects. (!)

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Post by carlosfm » 04 Aug 2008 21:22

720mH inductance in a new MM cartridge is a disasterous design.
With modern magnet materials these high inductance values should be a thing of the past.

bjohng
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Post by bjohng » 29 Aug 2008 14:58

This has been a real eye opener.

My AT440ML/OCC has been in and out of my system maybe 3 times. Each time I hope either it would magically improve or my ears will become more tolerant. No such luck.

So given that this is a difficult cartridge but one that supposedly is worth the investment of time it seems that breaking it in should be complete before playing with the loading.

Is break in mechanical or electrical?

Do you have to play a side over or can you just leave it in the run out grooves for a week?

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Post by bjohng » 30 Aug 2008 14:57

Fortunately I built a Hagerman Bugle Phono preamp some time ago. The PCB provides space for additional parallel resistors. Using surplus/cut off diode wire as vertical extensions allows for really quick changes of resistor.

With something like 20+ hours on my AT440ML/OCC and resistance down to 23K, it is definitely starting to sound quite musical. Here's where I have a problem.

Because the change is so easy I will continue to drop the resistance until everything goes dark - then work back up. I suspect that finding the optimum point in my system will take some serious listening time.

I am surprised by what appears to be an extreme divergence from "manufacturers recommendation" not just for my AT but other cartridges listed here on the forum.

However, the hype on this cartridge would appear to come from sources who wouldn't know one end of a resistor from another! Is this a case of "consider the source" or were they lucky enough to come out of the box ready to operate at 47K?

Can anyone explain this?

missan
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Post by missan » 30 Aug 2008 15:32

Remember what we actually are listening to are a chain of different components. That will mean that if a cartridge is sounding brigth, dark or whatever is to a large extent depending on the mechanical issues with the TT. Then we have the phono amp, the pre amp, the power amp and the speakers. A loading adequate for one set up could be totally wrong for another. To me the complicated mechanical behavier of the TT have a very big fingerprint at how it will sound.
missan

Wulf

Post by Wulf » 02 Sep 2008 07:07

I think Dial-a-Load is great. Sounds like a washing machine from the '50s.
LOL! :D
How about PTAK - phono tuning adjustment knob.
This is (almost) a Klingon swearword :shock: ;)
or PRC - phono resistance control.
Peoples Republic of China? I don't think so :roll: :)

delcam1n0
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Post by delcam1n0 » 02 Sep 2008 07:57

What about CCFF guys??

Compulsive Cartridge Fiddlers Facility :lol:

Have fun Chairguy, and post us some pics!!

For those of you wanting to experiment similarly
but at much reduced cost: One still can buy the
Pioneer C21 preamp, no tonecontrols, fantastic
build quality at less than US$200 on US eBay.

Facilities there include switchable:
C21: 100, 150, 200, 300, 400, 500pf
C21: 100, 10k, 25k, 50k, 75k, 100k
(see: https://www.hifiengine.com/manuals/pioneer/c-21.shtml )

as well as one of the best volume controls I ever
used.

Other HiQ Japanese preamps from that era (e.g.
Yamaha, Kenwood & Sony) did include similar
controls so my guess is that at least some hifi nutters
from that era had at least a vague idea what proper
loading could achieve....

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