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PARAGON

DIY Turntable?

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Hi was wondering if anyone has built a simple, good quality turntable perhaps using another to donate parts etc? I have no problem building a plinth (out of solid oak preferably). Anyway, any advice, opinions or helpful links appreciated!
Steve
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I am, one day, going to take the turntable out of a Technics SL5 and mount it in a plinth with an RB300 arm which has been rewired with silver litz.

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One or two over the years.

I like an LP12 bearing subplatter and platter, they're hard to beat for accuracy and balance and ease of fitting and you can do all sorts to them. Any old motor will do with the right size pulley, or the wrong size pulley and a speed controller. 

WHat are you planning, high mass, low mass, suspended, none suspended, boggo arm, uni, air bearing????

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One or two over the years.
I like an LP12 bearing subplatter and platter, they're hard to beat for accuracy and balance and ease of fitting and you can do all sorts to them. Any old motor will do with the right size pulley, or the wrong size pulley and a speed controller. 
WHat are you planning, high mass, low mass, suspended, none suspended, boggo arm, uni, air bearing????
Hi, I haven't any particular thing in mind, just fishing for ideas.

Steve

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For direct drives there is the Phainn kit that could act as a starter

https://theartofsound.net/forum/showthread.php?59341-Build-your-own-DD

For belt drives I would go with the sq225917 suggestion of Linn bearing and inner platter which can often be picked up quite cheap. The Linn bearing is probably about as good as you can get and I have seen a claim that the use of an oil bath is beneficial. However bearings can wear out so quality of second hand components may be an issue.

Linn outer platters are quite pricey even second hand ie north of £100 so costs would mount up. Linn Axis or Basik platters may show up cheaper but are much lighter than LP12 platters so less flywheel effect. A Thorens TD150 outer platter will also be a good fit and they can be had quite cheaply..

Edited by cre009
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Don't worry about LP12 bearing wear, just use a teflon thrust pad, 5% glass fill will be enough to stop droop. Then you can dick around with mag levving the sub platter and all sorts. Thick silicon oil to load down an AC motor to eliminate cogging, all sorts of stuff.

This is mine with the old AC set up, now running a DC tacho control. Kuzma stabi s 12" with LP12 bearing, subplatter and outer.

6812725392_0f7e8476cc_b.jpg

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sq225917 - impressive - nice stuff there - how did you go about the DC tacho control. The Mober unit is the most inexpensive commercial unit I am aware of for LP12s and that costs loads.

I am using the Peter Moncrieff article as a reference and I can see that tacho units may resolve some issues mentioned.

http://www.stefanopasini.it/Audio_Moncrieff.htm

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I'm running a Mober, good little unit, speed stability is spot on and the motor is physically quieter than the Rega 24v unit it replaced. That was run with a DIY sinewave regen unit with dual mono chips amps driving the output, speed, adjustment and and phase offset in 0.01 hz and degree steps.

The lighter and smaller DC motors all drift with varying load and temperature. I run thick, 20,000 weight silicon oil in my bearing, this utterly swamps stylus drag variation so the motor sees a constant load, the tacho just has to comp for temperature. There was a fair bit of fine tuning the viscosity to deliver enough drag, but not too much to upset the fuzzy logic of the feedback from the tacho.

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14 hours ago, sq225917 said:

I'm running a Mober, good little unit, speed stability is spot on and the motor is physically quieter than the Rega 24v unit it replaced. That was run with a DIY sinewave regen unit with dual mono chips amps driving the output, speed, adjustment and and phase offset in 0.01 hz and degree steps.

The lighter and smaller DC motors all drift with varying load and temperature. I run thick, 20,000 weight silicon oil in my bearing, this utterly swamps stylus drag variation so the motor sees a constant load, the tacho just has to comp for temperature. There was a fair bit of fine tuning the viscosity to deliver enough drag, but not too much to upset the fuzzy logic of the feedback from the tacho.

Any DIY options out there for a Tacho system? There are a couple of threads at Diyaudio but beyond my expertise.

I have been assembling Linn and other bits to have a go at something but still assessing options.

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On 16/11/2018 at 19:41, Danielquinn said:

I have had no speed drift from my maxon motor during use. A few tt manufactures would agree. 

How do you know, what's your test measurement set-up?

Any manufacturer who claims perfect speed stability with a DC motor without optical, magnetic or electric feedback and control is just plain wrong. It's an inescapable engineering truth. DC motors drift with load and temp variance.

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Cre, 

      The Tacho threads are pretty deep lots of big math and programming, not my skillset either.

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13 hours ago, sq225917 said:

How do you know, what's your test measurement set-up?

Any manufacturer who claims perfect speed stability with a DC motor without optical, magnetic or electric feedback and control is just plain wrong. It's an inescapable engineering truth. DC motors drift with load and temp variance.

You may measure speed every 5 mins. I prefer to listen.

As for your engineering truths . I would have a word with maxon. There motors are used in all kinds of environments. Turntable speed is a doddle  of an application.

So it's you with your myths or maxon with their empirical experience. I wonder who is should trust.

Edited by Danielquinn

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