On 03/07/14 15:57, Anton Aylward wrote:
On 07/03/2014 10:13 AM, michael norman wrote:
On 03/07/14 14:58, Per Jessen wrote:
Anton Aylward wrote:
On 07/03/2014 09:02 AM, michael norman wrote:
Laser pickups were available in the 70's they didn't work.
Sort of, depending on your definitions of those various terms.
IIR B+O had a series of players that had a true parallel tracking arm, that unlike the radial arms did not need the _varying_ angular pressure to move the arm inwards as it followed the spiral of the groove.
The Beogram 4000 (for instance, there may have been others).
I know, I saw reviews of it at the time, others tried to do the same thing.
AFAIK none of those products is in existence now, nor does anybody serious in audio engineering use one.
The concept didn't work.
Neither did the concept of true parallel tracking arms work either.
It DID so work. The thing is that given the technology available at the time it was in the same class as building 250MPH sports cars or cars where the only sound when cruising down the M1 at 90MPH is the sound of the clock ticking in the dashboard. There were people who would pay for that and did and appreciated the result.
Then along came Cds which offered a solution to many of the problems that beset Vinyl for a fraction the cost. Yes they had teething problems and production volume problems, but they rapidly became the 'Ford model T' not least of all since by 1990 anyone who could set up a garage band and a PC could burn a aster CD and have them mass duplicated for a couple of cents a copy. I knew quite a few people who did that, not only for audio but for advertising features, documentation, and of course software.
Today we know lasers and control systems much better and have more OTS stuff to make it all work. In many ways the parallel tracking is no different from the issue with a 3-d- printer and there are plenty of home-brew examples of that using Arduno boards and Pis.
But if a hobbyist wanted to build a vinyl-to-usb device its a lot easier to pick up an old Dennon or Sony or Akai swinging arm deck and an old pre-amp and use that than take the model of a 3-d printer and modify that to sit above a turntable.
All that being said, there were many variations on this, not least of all the Sony vertical version. The ones that had servo-feedback that relied on the torquing of the pick-up were really just a complicated servo-feedback version of a radial arm, and sensitivity of the torque measurement and the servo feedback were a complication, as anyone who has ever designed feedback control servo systems will know.
Which is why the laser sensor was such a superior system. Like everything else, you got what you paid for.
To follow my analogy with sports cars: there were many other sports cars, but the difference between the Ferrari or a Porche and them was clear when it came to maintenance, road holding, stability and so forth. Oh, and failure modes! 1960 era Lotus looked cool but had all manner of technical problems.
The real point here is that you cannot compare a B+O against a Dennon.
But these devices never found a market, and AFAIK are not being produced now. Mike
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