I can only think of one Japanese manufacturer still making DD tables. Who else is left?
I've never owned a DD table, so cannot confirm via personal listening tests what the sonic differences might be. But that doesn't make the servo circuit go away. It is still there! It does operate with lag and it does perform corrections within the audio band. I just can't say how noticeable it may be. Some tables will be better than others, obviously.
Belt drives have issues too, with elasticity, pulley tolerances, etc. The key difference will be if there is a negative feedback servo or not.
The problem is similar with linear regulators. They also operate with a servo within the audio band, reacting to changes in audio signal (unless circuit is balanced or class A). In this case I have heard the differences. It is even more pronounced when the audio circuit uses feedback. Now you have two servos working against each other, each with a different step response! If the filtering is not done well, the effect is a bit of "technicolor" brightness, sort of like the "sharpness" control on an old TV. A little bit may be good, a lot is bad. The sound can get shrill or smeared.
Of course, if you are a DJ doing scratching, then DD is the only way to go. You need that torque. :)
I've never owned a DD table, so cannot confirm via personal listening tests what the sonic differences might be. But that doesn't make the servo circuit go away. It is still there! It does operate with lag and it does perform corrections within the audio band. I just can't say how noticeable it may be. Some tables will be better than others, obviously.
Belt drives have issues too, with elasticity, pulley tolerances, etc. The key difference will be if there is a negative feedback servo or not.
The problem is similar with linear regulators. They also operate with a servo within the audio band, reacting to changes in audio signal (unless circuit is balanced or class A). In this case I have heard the differences. It is even more pronounced when the audio circuit uses feedback. Now you have two servos working against each other, each with a different step response! If the filtering is not done well, the effect is a bit of "technicolor" brightness, sort of like the "sharpness" control on an old TV. A little bit may be good, a lot is bad. The sound can get shrill or smeared.
Of course, if you are a DJ doing scratching, then DD is the only way to go. You need that torque. :)