Hall Effect Pick Up

[poynton]

Has anyone produced a pickup based on Hall Effect ?


Andy

[JonSnell Electronic]

Sony and Panasonic for many years use Hall Effect pickups to determine the state of the mechacon assemblies in most moving chassis like Video recorder/players and camcorders etc. Even in the car cassette machines by Grundig.
They are used as position sensors.

[levistubby]

I assume that the OP is talking about phono pickups (cartridges).

[JonSnell Electronic]

Originally Posted by levistubby

I assume that the OP is talking about phono pickups (cartridges).

If OP is speaking of phono then as a Hall Effect works like a switch, I doubt there is enough signal variation for one to be useful.

[poynton]

Originally Posted by JonSnell Electronic

If OP is speaking of phono then as a Hall Effect works like a switch, I doubt there is enough signal variation for one to be useful.

A hall effect device does not work as a switch.

It can output a voltage proportional to the change in magnetic field.

Being very small, it does require amplification.


Andy

[scott wurcer]

As they say, "The Hall effect is a small effect". IME the SNR of a Hall cell used in analog mode is pretty bad. The mechanical issues of building a cart with a Hall cell bridge and a strain gauge are similar (but now you need a big static magnetic field), I don't know if it would be worth the bother.

[Straight Tracker]

Originally Posted by poynton

Has anyone produced a pickup based on Hall Effect ?


Andy

Hello Andy,

Not to my knowledge. However, I don't see why it can't be done. The basic Hall element is an analog device. By the time it gets manufactured into a usable chip, it can be a digital switch or a ratiometric analog device. I have been using Hall effect devices since the early 1980s as position sensors in my various tone arm experiments when they were still being made by Sprague Eectric which is now Allegro Micro Systems. You can buy one for $2 or $3 fom Dgikey which is cheap enough to do some experimenting. They will need a 5v supply and need a total of four wires if you do stereo. I use one in my newest tone arm and I use the same gage wires as I use for the phono cartride itself. It would be interesting if somone actually did this.

Sincerely,

Ralf

[PRR]

Here is a kinda-suitable linear Hall sensor:
http://www.bristolwatch.com/hall_effect/ugn3503.pdf

I am not a phono needle designer. I'm guessing that even with a speaker magnet (5000 G) it would be hard to get 1 G deviation from a small stylus. That would be like a milliVolt which might be OK. But the broadband hiss is 80uV which is 100X or 40dB worse than conventional needles/amps.

Yes, modern Neo-whatzit magnets can put a very strong field in a very small area with little weight. But I'm guessing to get the signal level well out of the hiss they would have to be strong enough to suck paper-clips.

Small effect indeed.

[luckythedog]

The sensor would need to be the moving part, set in a phenomenal local field. It might just work, given semiconductor sensors can be tiny and modern permanent magnets made to precision gaps in small dimensions with phenomenal strength...…..

Not much dafter than fishing MC signals out of the noise mire all things considered when one thinks about it? That works, after all.

LD

[Halejok23]

Creating a Hall cell bridge it isn't so easy but it is simmilar to whitestone bridge connected to Strain Gauges? Couse as the strain gauge formula saying that electrical resistance should be simmiliar.