Why do turntables sound different?

Yes,  and perhaps more often built to a price point jeopordizing performance potential.  

Yet, there are those who gave up their Walkers and other high end tables and use highly modified Technics SP-10 MK III while claiming this set-up's with various arms and cartridges superiority. I would be happy to compare if I could. Most likely outcome is that it would be different with the advantages and disadvantages of either, and also a matter of taste and the synergy of the entire chain. At the highest level I believe you have to match everything, including turntable to speakers. The system should work in complete oneness. This would take enormous effort, but that's the only way. Science is science but art goes beyond it.

inna,

I think that almost everyone on these forums, think that they are applying science and art to their system at whatever level they are at.

Few mention that they are new to this hobby.

Fewer mention that they are wannabes.

 I mostly agree with your comments. But, unless you have your Studer and have it fine tuned/ calibrated and your tapes match the calibration of that Studer; your almost in the same boat as the TT / vinyl people. I may be wrong on this point; perhaps you or Ralph can comment and clarify.

 I will still wait for the Technics 10R.

It would be great if you would post your system with pictures. Help us visualize. 

Thanks and Best

Oh no, I don't have Studer, that's my future project, but I am familiar with good tape sound. And I certainly would not get any high-end table without comparing it to the tape. As for proper alignment and calibration, I would leave it to professionals, there are still people who know how to do it. It is also how I would choose speakers - with Studer or Ampex as a source. And if I was a crazy audiophile millionaires I would also move along three sets of electronics - solid state, hybrid and tube to audition speakers. Let's say, Gryphon for solid state, Ypsilon for hybrid and Lamm for tube. 
Some would say why such an effort, just get Continuum and that's it. They might be right but they might be wrong too. So, speakers frst, 'wire with gain' second, turntable/arm/cartridge/phono last.
nkonor, why are you so sure about that Technics ? Do you already use Technics and want to upgrade? It's expensive stuff.

We are not really closer to answering the original question. In essense, the only kind of answer we have so far is they just do sound different. Or, they just color the sound differently and that's why they sound different. The exact science behind it let alone art remain elusive.