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bauzace50

Turntable motor: AC versus DC

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Greetings,

This question was also posted at another forum, but it cannot harm to ask in this distinguished venue, also:

Do you know about the virtues of AC and DC motors used in turntables? How do they compare with one another?

The motor in most turntables is the AC. A few ones use the DC, to include Origin Live, to my knowledge.

Any comments? Thankyou,

bauzace50

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well it's very quiet around here at the mo, so my semi informed answer is simply that DC current suffers far less from voltage and therefore speed variation. Its about pitch stability, but I expect someone engineery electrical will be along shortly to explain why there's much more too it than that. Bet they use words like buffer and capacitance and modulator.:)

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In years gone by DC motors were shunned in TT use & hence if one was fitted it was likely to failure even tho' the likely resultant audio performance would be very good, enter the Pink Triangle/s.

DC motors, by thier very name will require some electronics to run & so maybe due to this extra cost there are few fitted today.

It's possible I guess a beefy AC motor has better inertia therefore keeping the platter at a more stable revolution but perhaps at the expense of greater vibration over DC which you would expect greater control through (less) precision electronics.

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Yes, I have an AC motor and the seperate power supply made a huge difference :)

OMG I sound like a Naimee :shock:

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Guest sq225917

there's no difference between well implemented examples that address the inherant weakenesses of each motor design.

one is as good as the other.

AC regulated mains frequency and trimming of phase angles.

DC good servo control that doesn't hunt too much or overcorrect.

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i thought the main differences were:

AC has better speed stability as the speed is regulated by the mains frequency (50/60hz) therefore you fit and forget (and don't adjust the speed). a good power supply is where the up-grade / qualitylies. Downside is AC motors vibrate, which is fed through the belt to the platter.

DC's don't vibrate (hence why direct drives use them) and speed is controlled via the mains and a transformer for voltage andmost DC motors have tiny adjustment screws or some other meansfor fine tuning the speed. downside is they can need regular adjustment depending on the unit and the mains supply. benefit is they are much smoother and don't vibrate.

pink triangles used both, altough most usedAC (PT Too, LPT, Export)it was only the Anniversary that really mde the most of a DC motor, as it's smooth running allowed it to be mounted on the suspended sub chassis with the arm board and bearing.

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It's not entirely true that DC motors Don't vibrate at all; the way they vibrate is quite different to an AC motor though and is much less 'peaky'. Many (though not all, and it depends on which you are comparing) DC motors have less torque than similiar AC motors.

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Ah, Oh,

goodness, it looks like a Polarizationbrewing. Tea lovers vs. coffee lovers! Both have caffeine, butboth aredifferent for other reasons. Similar to mc vs. mm!:shock:

I am unable to harmonize these for lack of knowledge...the initialreason for my question. But it's VEWY INTEWESTINGH! Thanks, all.

bauzace50

P.S.- this theme is being developed alsoin http://www.vinylengine.com link onto"Turntables", and then link onto "TurntableMotors: AC vs DC". Interesting views, and some polarization, also.

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