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All-Analogue Turntable

New opportunities for both expense, complication and "warmth" for your HiFi
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The good old record player, phonograph, turntable or "deck" if you're a youth, has been around for some time. They're theoretically simple devices, it's just turning a circular platform around at a constant speed while having an electrically coupled needle track a groove. Traditionally, A simple AC motor would spin at a rate dictated by the mains frequency, and be geared down to drive the platter. Subsequently, various sophistications have been bestowed upon the humble device, such as direct drive by DC motor and pointless LCD displays. Now, many HiFi enthusiasts will tell you, whether you like it or not, that sophistication has its place. That place is largely outside of HiFi, because modern sophistication introduces "coldness". Worse, this modern sophistication creeps... back in the old days, you could rely on a high end analogue sine wave from your mains supply. Nowadays, there's layers of ugly digital control equipment that probably introduces horrid square edges hidden in the power supply, or what about those wind turbines? One gust in the North Sea and you've got harmonic resonances from blade flex transmitted right into the middle of your lovely Dave Gilmour solo. I think we can fix this.

The key here is to eliminate all that nasty digital influence. We'll start by making a new power supply, in a separate case, naturally. Next, the turntable motor. I think a brushless DC motor. Normally, they use rare Earth magnets for efficiency, but I think some old-school AlNiCo magnets sourced from melted down Telecasters will do the job better. Next is the tricky problem of control. Brushless DC Motors are becoming so popular principally because of the newly affordable control electronics <link>. Now, see figure 3? Those 6 diodes and transistors could easily be replaced by the sort of power amplifier vacuum tubes/valves favored by the HiFi community. In front of those an series of analogue signal generators set to 33/45rpm feed the necessary speeds.

The downsides are confined to just massive inefficiency, high cost, complexity, fragility, size, weight and poor reliability.

bs0u0155, Jan 07 2016

Brushless DC Control http://www.digikey....ss-dc-motor-control
[bs0u0155, Jan 07 2016]

cavitation machining https://www.google....avitation+machining
Prior art for [Ian]'s idea [notexactly, Jan 11 2016]

[link]






       Some turntables use laser beams instead of needles to detect the data on the disk. This can be a pure-analog process, too, and avoids wear-and-tear on the disk.
Vernon, Jan 07 2016
  

       But the wear really takes some of the harshness out!
bs0u0155, Jan 07 2016
  

       Cylinders not platters, shirley.
FlyingToaster, Jan 07 2016
  

       // The downsides are confined to just massive inefficiency, high cost, complexity, fragility, size, weight and poor reliability. //   

       The UK MoD will buy all you can build, straight off the line. Don't bother to wrap them.
8th of 7, Jan 07 2016
  

       My HMV model 101 is completely analogue already, no digital signal processing anywhere in the system - the power supply is smooth on a macro scale unlike yours with its oscillators introducing unnecesary fluctuations - and it has the warmest, most transparent sound imaginable.
pocmloc, Jan 07 2016
  

       For nice, smooth DC the solution is obvious; a lead-acid accumulator, in a glass case so it's possible to see the plates, the acid level, and the bubbles.   

       40 cells in series will give you the 90V for the valve H.T. supply, with a separate 3-cell battery for the heaters.   

       It should be charged (offline) by a small stationary steam engine driving a dynamo.
8th of 7, Jan 07 2016
  

       I'd prefer to use the steam engine to directly drive the turntable. Nothing smooths out spikes in the power supply like a 1-ton flywheel.
hippo, Jan 07 2016
  

       The steam engine could mechanically drive the platter, with a large shiny governer to control the speed.
Ling, Jan 07 2016
  

       //It should be charged (offline) by a small stationary steam engine driving a dynamo.   

       Meh. My buddy had this set up, and even with his speaker wire extruded from a 2000-year-old nail pulled from the true cross, it still had tinny, harsh highs.
the porpoise, Jan 07 2016
  

       There's some 4000 year old copper handles in the Giza pyramid "air shaft". Just think of the perfect crystal structure...
Ling, Jan 07 2016
  

       hippo, – couldn’t a person combine a potters wheel and record player?   

       I haven’t touched a record deck since my teenage years and my pair of Garrard SP25III decks.
Ian Tindale, Jan 07 2016
  

       I suppose my hand-crank Victrola suffers from a degree of digitation, too, as the gears inside it have squarish edges. Maybe a belt-drive in the wind-up mechanism would be better?
RayfordSteele, Jan 07 2016
  

       //I'd prefer to use the steam engine to directly drive the turntable. Nothing smooths out spikes in the power supply like a 1-ton flywheel.//   

       Allow me to introduce the 1.05 ton cryogenically treated copper flywheel. The install conditions are set so that the flywheel stays in the solid phase. This clever engineering ensures that all the neutrons don't end up at the rim with a cloud of electrons struggling around at the center.
bs0u0155, Jan 07 2016
  

       //The UK MoD will buy all you can build, straight off the line.//   

       I am currently able to build them faster than F-35's and they have a better chance of working. I can't see me getting the gig, after all, I haven't massively over promised.
bs0u0155, Jan 07 2016
  

       For smooth rotation with no bad effect from gears, finite number of DC motor phases, or variation in the temperature of your steam boiler, the turntable should be direct driven from a Tesla turbine with water from a large reservoir. Contact your local swimming pool installer for a quote.
scad mientist, Jan 07 2016
  

       Yes but think of the cavitation and turbulence!   

       I'm thinking that the turntable should be hand-spun by a swarthy muscular half-naked slave. That would give everything a real human sound.
pocmloc, Jan 07 2016
  

       // they have a better chance of working. //   

       Over-unity powerplants and time-travel devices have an even better chance of working; interestingly, those concepts don't quite have all the laws of Physics operating against them ...
8th of 7, Jan 07 2016
  

       That reminds me of a question I recently wanted to know the answer to. Can cavitation be used to constructively alter shape of forms*, or only to destructively alter shape of forms?   

       * by which I don’t mean to add matter, but rather, to not take away matter.
Ian Tindale, Jan 07 2016
  

       How to get around the digitization of quantum mechanics? Maybe it could be rotated by some interaction with dark matter?
RayfordSteele, Jan 07 2016
  

       The problem is, ears are digital.
MaxwellBuchanan, Jan 07 2016
  

       [Ian Tindale], so using cavitation as a machining process? Interesting idea...
neutrinos_shadow, Jan 07 2016
  

       Isn't sound propogation through the air also digital, when you get down to the level of quantum interactions between atoms of air>
pocmloc, Jan 07 2016
  

       Not really. Quantumtude doesn't mean that everything is quantized.
MaxwellBuchanan, Jan 07 2016
  

       //The problem is, ears are digital//   

       So are muscles in the guitarist/drummer/violinists arms..
bs0u0155, Jan 07 2016
  

       mmm OK.
pocmloc, Jan 07 2016
  

       [Ian] yes, experiments confirm that you can play records on a potter's wheel
hippo, Jan 08 2016
  

       //eliminate all that nasty digital influence//

I may just be imagining this but I am pretty certain that I saw, in my youth, someone playing a vinyl record on a hand powered turntable and using a needle stuck through a piece of corrugated cardboard; eliminating the need for electricity as well as any nasty digital influence...well except for what was used in creating the record in the first place, obviously.
DrBob, Jan 08 2016
  

       //The problem is, ears are digital.   

       So are fingers.
the porpoise, Jan 08 2016
  

       Heh.
bs0u0155, Jan 11 2016
  
      
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