I was reading about an interesting type of phono cartridge (called 'strain gauge') from the 1960's/70's on another forum. Apparently these cartridges modulated an externally applied DC voltage rather than generating a weak voltage like mm and mc carts (unless I'm not getting the right impression):

http://db.audioasylum.com/cgi/m.pl?forum=v...191767&session=

I suppose it's a bit too late in the analog game to talk about bringing this idea back, but nonetheless I find it fascinating... there's almost nothing on the Web as far as further infos (almost nobody else has heard of this, I assume... ). Hey, if it can't be found via Google it has to be interesting...

It reminds me of piezo cartridges. Exept that piezo cartridges generate themselves a voltage, unless maybe the voltage is too low and this system is actually the piezo one.
Piezo cartridges are the worst of all. They were used in portable "Teppaz" turntables.