Needles?

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Lah Ca
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Re: Needles?

Post by Lah Ca »


Hoodoo
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Re: Needles?

Post by Hoodoo »

Good point about the tracking force, Lah Ca

Hoodoo
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Re: Needles?

Post by Hoodoo »

Well, a few days ago I made a needle from a tungsten TIG electrode, the 1/16” size, and played a good condition record that I do not care for much (I Miss My Swiss, Victor 19718) ten times without changing or resharpening the needle. The record seemed to suffer no damage and the needle showed only about as much wear as a normal needle suffers after a single play.
Yesterday, I saw on Ebay, from a seller in California, some old stock needles that I think are also tungsten but, like mine, in the form of normal needles.
I include pictures of my needle, posed beside a loud to e steel needle, and the ones from Ebay, though the pictures seem to want to load in the opposite order of what I intended.
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Lah Ca
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Re: Needles?

Post by Lah Ca »

@Hoodoo

Interesting post. Thx.

I have been using the Swiss-made Pfanstiehl I purchased earlier (simply because I have them and they are the only loud tone and soft tone needles I have at present).

The loud tone ones seem a bit over the top - as in very loud, uncomfortably loud.

The soft-tone ones are quite pleasant. I have not been pushing these needles to their advertised limit of 12+ plays but have been more or less treating them as normal steel needles, using them to play both sides of a disk before tossing them - viewed with a numismatic hand lens, they show no observable evidence of wear, unlike, say, the medium tone standard steel needles I also have. There are disks I do not much care about, and I have played them repeatedly over a period of days with the soft tone Pfanstiehl needles. I do not notice much/any change in the sound from the disks as the number of plays increase. This is all highly subjective, however. If I wanted to study this in an objective manner, I should be setting up mics and digitally recording all the plays and then looking for evidence of deterioration in sound in something like Audacity, doing A-B comparisons of widely separated plays, etc.

JohnM
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Re: Needles?

Post by JohnM »

It’s not “less mass” that affects volume, it’s the flexibility of the needle in relation to its diameter. The soft-tone needle flexes more and transfers less vibration to the needle bar. This is called ‘compliance’. In the Theory of Matched Impedance, which correlates mechanical and electrical forces, compliance = capacitance.
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Lah Ca
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Re: Needles?

Post by Lah Ca »

JohnM wrote: Tue Jan 04, 2022 7:24 pm It’s not “less mass” that affects volume, it’s the flexibility of the needle in relation to its diameter. The soft-tone needle flexes more and transfers less vibration to the needle bar. This is called ‘compliance’. In the Theory of Matched Impedance, which correlates mechanical and electrical forces, compliance = capacitance.
Interesting. Thx.

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Inigo
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Re: Needles?

Post by Inigo »

And the needle mass is associated inductance, added to the mass of the needle chuck and thumbscrew; indeed all the masses placed before the vibration arrives to the rotation axis.
Inigo

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Marco Gilardetti
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Re: Needles?

Post by Marco Gilardetti »

Time to revive the "super loud needles with added masses" topic, methinks...

As it is well known, the loudest of all needles have added masses, in form of a flat cylinder or a piano wire wounded around the shaft. In both cases, and in the second especially, this seems to elude the logical principle of more mass => less flexibility => more output.

Can someone shed light on why adding mass to the tip can increase the "loudness" of the needle?

HMVDevotee
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Re: Needles?

Post by HMVDevotee »

In principle, I agree with JohnM. I've re-read Marco's original post and this current one as well and have one observation; the amount of force necessary to accelerate the mass of the entire apparatus, including both sides of the fulcrum of the reproducer, and deflect the diaphragm (which is essentially a spring), represents the inertia of the system. Ergo, increasing the mass of needle without some improvement in it's physical properties simply adds to that inertia, or overall resistance to movement. To wit, when I first play a cactus needle, long and tapered to very thin point, it is very quiet. It grows louder as I re-point it (shorten it.) In the end, when the same length as a soft tone steel needle, some are as loud as the steel. Although I haven't weighed them, I'm fairly sure the mass of the cactus needle is less than the steel.

Lah Ca
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Re: Needles?

Post by Lah Ca »

Ever wonder what weight your gramophone tracks at?

Being curious I decided I would try to measure the tracking force on my Aeolian Vocalian.

I do not have a scale out for my turntables that goes high enough for my gramophone, but I dug around and found the old plastic balance scale that came with an AR turntable that I had decades ago. According the instructions for the scale an American copper penny is about 1 gram. I went and found the bag of copper pennies that the family uses as game counters and started taping them up in rolls of 10 so that I could stack them. The pennies were a mix of Canadian and American coins, so this isn't overly scientific. When I reached five stacks of ten pennies (very approximately 50 grams plus the weight of the tape), the tone arm started to lift. I would have needed to add more pennies to get the scale balanced, but it was becoming impossible to stack them.

So I would say that with a wide margin of error, my gramophone has a tracking weight in the region of 50 grams or more.

This is an interesting observation when considered in relation to the use of multi-play needles (which were intended for electrical cartridges) in acoustic gramophones. The BBC study of 1937/38 concluded that multi-play needles did not damage records when used repeatedly. They were of course using electrical cartridges, ones used for radio broadcasting, in the study. What is the range of tracking weights for early electrical cartridges? 5 grams? 10 grams? Would the conclusions change if the multi-play needles were used repeatedly at a tracking force of 50 grams plus? I wonder.

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