Elektor Electronics new website

Oh gosh, it was much "cleverer" than that... Cantilevering the needle's base between the two halves of the piezo allowed for very accurate side to side movement of the tip by a few micrometers, far more precise than a gramophone's needle.

A piezo gives far less displacement per unit volt applied. Several volts for a few micrometer span. It also has a low mechanical source resistance so that displacement is decently proportional to the voltage applied, even against the back force generated by the electric charge between the needle and the baseplate.

Also a cartridge is a velocity response device, difficult to use in a closed loop positional system as required for a microscope.

Have a look at the groove pitch on an LP, and then consider that signals well over 40 dB below that can be recorded and played, preserving the waveform.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I think you're thinking of magnetic cartridges. There are also piezoelectric cartridges, popular in cheap record players in the 1950s because they gave nearly a volt of output (with high impedance of course), suitable for amplification by a single tube.

I read in sci.electronics.design that ted wrote (in ) about 'Elektor Electronics new website', on Sat, 26 Feb 2005:

You clearly speak of what you do not know. Piezo phono pickups are

*amplitude* sensitive, in that the give a flat response with the RIAA amplitude/frequency curve. **Magnetic** pickups are velocity sensitive.

There are 'crystal' phono pickups, using Rochelle salt bender bimorphs, and 'ceramic' pickups, made of barium titanate, also bender bimorphs. These have capacitive impedances, corresponding roughly to capacitors of

600 pF to 1.5 nF. Typical open-circuit outputs from a 1 kHz 5 cm/s recorded signal range from 1 to 8 mV.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I can see there is a bit of a misundertanding here.

The equipment in the article didn't use a gramophone cartridge (neither magnetic, piezo, crystal or any other kind)

It used a steel needle attached to a piezo crystal (as found in a piezo sounder for example) The metal electrode was split to provide a tiny differential motion to the needle.

Elektor have responded to the problem - their response is to only provide free .pdf files if the layout was not printed in the magazine. If it was, no free file any more.

They have started deleting my questions on their forum - they are trying to censor the issue.

Please understand that I am not the dirt-stirring type. I have been a reader of Elektor since 1983 and am simply amazed at what they have now done, and disgusted.

Again I would ask anyone who would like to continue having access (without paying more money) to the PCB .pdf's to email Elektor and complain.

Rick.

I agree.

The PCB file is pretty useless without the article text, so who cares if someone grabs it for free. They'll still need to buy a magazine, or subscribe.