MC Cartridge De-magnetizing software for PC soundcard? - diyAudio
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Old 20th January 2004, 04:02 PM   #1
KBK is offline KBK  Canada
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Exclamation MC Cartridge De-magnetizing software for PC soundcard?

This is one thing that has always bugged me:

The basic requirements for demegnetizing a MC cartridge, is merely the waveform and decay envelope for a signal.

None are likely to be propietary, and none are likely to be difficult to define mathematically, or to copy, refine and then have come out of a soundcard on a PC.

Does anyone have a preamp for their PC and the ability to store the waveform off of a MC demagnetizer?

I have plenty of high powered solid state lo-z out Preamps around that can put out the signal required for demagentizing even the lowest output MC cartridges. All I need is that signal trace...heck, even a intergrated amp at low output would be fine.

I am sure the rest of you could use it too.

Perhaps we could figure out how to set the intergrated amp level so that the voltage is not too high, like using the readings off of a specific cheap-widely available multimeter for setting the output of the intergrated...making sure the intergrated has the nessessary HF response, of course.

I've seen the waveform before, and it ain't that tricky. But of course, I'm lazy and ask for help...
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Old 20th January 2004, 04:18 PM   #2
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By all means a great idea. While you're at it why not collect some waveforms from cable-cookers as well
Such a waveform should be very easy to synthesise in coolEdit per example.

I have outlived a cupboard full of old MCs but never tried a demagnetiser. Is the effect really good?
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Old 20th January 2004, 04:32 PM   #3
KBK is offline KBK  Canada
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YES! Very much so. It restores the life of the units. Quite noticable. It tends to show best in the super low output units as they 'tend' to have the highest or higher charged motor structures. The moving components get megnetized and the cartridges sound muddy and slow, diffused, etc.

I used to use my signal generator and a saw tooth, or modifed sine wave on a power amp- with resistors, of course, at about a 15-50 watt load to cook cables. I would burn them for a full day.

I would make a wire run to to do the cooking that would leave the wires to be used almost *exactly* where they end up sitting..and then burn the wire in position, so to speak.

This would maximize the crystal linkages, with minimal disturbance after burning.....
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Old 20th January 2004, 05:25 PM   #4
sreten is offline sreten  United Kingdom
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I can't see the logic in this at all.

A tape head has zero static magnetic field and at low
signal levels any magnetism does have an effect.

Conversely a MC cartridge has a large static magnetic field
and it is impossible to demagnetise the soft iron parts.

There's no reason for any moving part of a MC to be magnetic,
and I don't know of any MC with magnetic moving parts.

The reason you can't buy an MC demagnetiser seems obvious to me.

sreten.
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Old 20th January 2004, 07:16 PM   #5
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Television CRT demagnetisers put out a very strong AC magnetic field.
The method of usage is to swamp the CRT with this high level AC field closeup, and then SLOWLY move the demagnetising wand a couple of meters away from the CRT before switching off the wand.
IOW, the active element is a slowly decaying AC magnetic field.
I think there are sig gen programs that can duplicate this.

Eric.
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Old 20th January 2004, 08:46 PM   #6
sreten is offline sreten  United Kingdom
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True, its the same way tape head demagnetisers work.

But I've a feeling this thread is related to the extremely
dubious, if not incredibly stupid concept of driving a MC
cartridge with reducing AC current to 'symmetrisise' its
response.

It doesn't take a genius to realise playing music will
have the same effect, so your only choice is to juice
up the amount of current, and you'll melt the coils
before this has any noticeable effect.

Utter and complete b*ll*cks IMO, sreten.
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Old 20th January 2004, 10:01 PM   #7
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Hi,

Quote:
The reason you can't buy an MC demagnetiser seems obvious to me.
To me too...
If anything a MC cartridge may require a remagnetising job...NOT a demagnetising one.

Cheers,
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Old 20th January 2004, 10:43 PM   #8
KBK is offline KBK  Canada
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You can buy a MC cartridge de-magnetizer any time. Go look on the net. And they work.

Have you tried one?

And yes, it is merely a pulse and then decay of a sine, but what time frame, envelope, etc.?

The Sumiko 'fluxbuster' was good one.

Don't diss what you haven't tried, however 'human-condition' such behaviour may be. Doubt, sure, but have you tried one????

I see why this forum has such hard rules about nasty posting. It is slowly showing it's face to me across the threads I have started or posted in.

Engineers need to get out of their textbooks and remember that the guys who originally wrote the rules were hammered in their own right....and were the stout visionaries of their times.

But that 'ole human condition......

There is another thing though; as it is with all the human senses.... it is the sheer ability to discern the differences ----it varies within the population.

Fact.

But let us not argue! , and get on to the business of fixing this issue. If you want to attack, go out and cut some wood.

If you want to discuss this cartridge demagnetizing and wire burn in issue, stay here and involve yourself constructively.

Thank you.
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Old 20th January 2004, 10:47 PM   #9
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Hi,

Quote:
The Sumiko 'fluxbuster' was good one.
Knowing what it does and how it works may help...
It's purpose is not to demagnetise the magnets of a MC cartridge.

Cheers,
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Old 21st January 2004, 12:46 AM   #10
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Originally posted by sreten
It doesn't take a genius to realise playing music will
have the same effect, so your only choice is to juice
up the amount of current, and you'll melt the coils
before this has any noticeable effect.

Any genius knows that music waveform is anything but a smoothly decaying sine waveform.

Eric.
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