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Diy TT project

Edd, all those times I called you a cheap bastid in chat. Well, um, I take em back. :D

Someday when this tadpole becomes a frog, I would love to make a DIY turntable. The one you are proposing just keeps getting cooler. Keep it up!
 
First of all, that is some top-notch work you are doing here!! Please forgive my ignorance, but how does the i-pod drive the platter?
 
The speed of an AC synchronous motor is derived based on the frequency of the AC being sent to it. The iPod, in this case, is supplying a stereo track of a certain frequency, with one channel 90 degrees offset from the other. This will provide the motor with the two poles it needs and the speed can be adjusted by changing tracks on the ipod. from the ipod, it will go into an amplifier that will be loaded by a step up transformer to ensure the motors get the proper voltage along with frequency.
 
dnewma04 said:
The speed of an AC synchronous motor is derived based on the frequency of the AC being sent to it. The iPod, in this case, is supplying a stereo track of a certain frequency, with one channel 90 degrees offset from the other. This will provide the motor with the two poles it needs and the speed can be adjusted by changing tracks on the ipod. from the ipod, it will go into an amplifier that will be loaded by a step up transformer to ensure the motors get the proper voltage along with frequency.
Click to expand...

Wow! That's pretty cool! Thanks Man
 
dnewma04 said:
The speed of an AC synchronous motor is derived based on the frequency of the AC being sent to it. The iPod, in this case, is supplying a stereo track of a certain frequency, with one channel 90 degrees offset from the other. This will provide the motor with the two poles it needs and the speed can be adjusted by changing tracks on the ipod. from the ipod, it will go into an amplifier that will be loaded by a step up transformer to ensure the motors get the proper voltage along with frequency.
Click to expand...

So how do you produce a track for the ipod to get a perfect 33.3 rpm? Sounds like an elegantly simple solution that makes my brain go :saywhat:
Cheers,
Tony
 
you use some software like audacity, you create a tone at say 60hz, then duplicate it, then offset the second tone 90 degrees. Then save as a wave file.

You then measure the speed on the tt, with a strobe or the like, then make the required track, say 59.5hz.
 
edd9000 said:
you use some software like audacity, you create a tone at say 60hz, then duplicate it, then offset the second tone 90 degrees. Then save as a wave file.

You then measure the speed on the tt, with a strobe or the like, then make the required track, say 59.5hz.
Click to expand...

:scratch2:
 
Why use an iPod when you can build a simple adjustable oscillator system?

Since you are going full-house on the machine you might as well do the drive system also. Why not simply use an Origin Live DC motor kit?
 
Because it isnt simple. You have issues with electronic noise, maintaining the phase seperation etc, all beyond my ability.

A look at Mark kellys Dippy oscilator circuit convinced me it was just as easy to use the ipod on hand.

the Origin live motor kit is $500 at least, so far i have spend around $160 to get to this point.

Im also a fan of ac sync motors vs dc, if i wanted to go dc id build the mark kelly dc motor controller with a maxon motor.

My next step will be a 3 phase drive using a maxon ec motor, much like the teres vertus, but thats a way down the road.
 
Machineghost said:
Why use an iPod when you can build a simple adjustable oscillator system?

Since you are going full-house on the machine you might as well do the drive system also. Why not simply use an Origin Live DC motor kit?
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I'm with the iPod solution. There is a certain poetic symmetry and elegance with using the latest invention in digital music playback to serve as the drive for an analogue music player that the iPod presumes to make obsolete :thmbsp:
 
thisOne said:
I'm with the iPod solution. There is a certain poetic symmetry and elegance with using the latest invention in digital music playback to serve as the drive for an analogue music player that the iPod presumes to make obsolete :thmbsp:
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That I understand :music: but there is always a but... :smoke:
 
Machineghost said:
That I understand :music: but there is always a but... :smoke:
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Id love to know what the but is? is it because its digital?

http://www.stereophile.com/budgetcomponents/934/index5.html

The ipod measures pretty well, with low distortion even in the area we are using it.

Using an uncompressed wav file, the 2 sine waves generated will be about as good as anything i could wire up.

Oh and with a remote ill be able to start and stop the lp from my chair :D
 
edd9000 said:
Id love to know what the but is? is it because its digital?

http://www.stereophile.com/budgetcomponents/934/index5.html

The ipod measures pretty well, with low distortion even in the area we are using it.

Using an uncompressed wav file, the 2 sine waves generated will be about as good as anything i could wire up.

Oh and with a remote ill be able to start and stop the lp from my chair :D
Click to expand...

Hell, you'd be able to fast-forward and (maybe) rewind it, too! (yikes!)


:smoke:
 
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