turntable sound

[skularatna]

why do turntables make sound...even when there is no cables have been connected. just the power. You can hear the music, albeit very faintly.

 

[nads]

it is the stylus doing its job.

 

[chebby]

What you are hearing is just the mechanical noise (as nads said) of the groove moving the stylus tip around.

Back in pre-electronic times this was the principle of those old phonographs with the giant horns on them. The 'stylus' was linked to a diaphragm which vibrated mechanically and was 'amplified' by the horn.

 

[fatboyslimfast]

 

[fatboyslimfast]

Joking aside, if you have an old worthless LP (anything by Val Doonican / Des O'Connor etc), you can make one of these by just rolling an A4 sheet of paper into a cone and putting a very small sewing needle through the end, and placing it on the record (obv revolving on the turntable platter). You'll be surprised how much volume it makes.

Just don't do this on anything you want to listen to with a regular stylus, as the sewing needle will create it's own grooves!

 

[chebby]

Any suggestions on mechanical RIAA for these things?

 

[fatboyslimfast]

Yep, if there ain't enough bass, use A3 paper instead of A4....

Seriously, you do raise a good point in that you will be hearing exactly what is on the record, i.e. very little bass (they reduce this to help cartridge tracking and track width, then boost it in the phono amp) and loads of treble (again boosted on the record, so it can be cut in the preamp, along with surface noise - bit like Dolby B for cassettes)...

 

[skularatna]

wow interesting stuff... I also learn the sound is caused by a Piezo Electric effect, with the stylus rubbing on the grooves of the record.

 

[fatboyslimfast]

Welcome to vinyl-geek-ville!

If you google "magnetic cartridge", you will find a wiki on it, which is quite informative...

It's also interesting to note that attempts to produce a laser turntable, which used a red laser to read the grooves rather than a stylus, were never totally successful, as the wavelengths on the record could (on a pristine copy) be smaller than that of the laser beam...

But I'll shut up now, before I become a bore!