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TW Acustic three motor unit

Since two weeks I have on loan three motor pad from my friends Black Night turntable. Today I have to return it and just switched back to my stock single motor.

When I first runned three motor pad I felt advantages and disadvantages of this unit. The sound become better but not in each aspect.

With three motor pad the bas was deeper and better separated. The attack of large drums in final of Mahler first symphony was simply spectacular. Three motor unit rocks on complex passages. Overal the sound become more dense, better separated and defined but there is a big but...
With three motor pad the airness and openess of the sound decreased and some "music flow" has gone.
The sound become more audiophile correct but a bit less musical at the same time.

Can you share your experience with AC1 vs. AC3 vs. BN motor?
Does anybody preffered AC1 instead BN motor?

I am puzzled.
milimetr
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tdaudio
201 posts
 
Milimetr, how did you make sure that you had the same amount of belt tension when comparing the one vs three motors. After dusting or moving the motor the Feickert tool is used to place it back to the same distance with in one or two millimeters.

From playing around with other belt materials and motor distances with the original belt one can hear differences in these things alone. Its not hard to kill the airiness with too much tension. Dampening is different
milimetr OP
139 posts
 
I suppouse that belt tension with one motor is smaller than with three motors. The belt tension with three motors is greater, simply because geometry of three motors around the table. It can be changed to greater tension but not to smaller tension.
So when we compare AC1 vs. AC3 the change in belt tension is inherent with this experiment.
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tdaudio
201 posts
 
Milimetr, Two things here. One how much the belt is stretched and two how much horizontal force the belt puts on the platter. Too much horizontal force hurts the sound.

With a one motor AC these both change together as you move the motor farther from the platter. It is straight forward in finding the sweet spot of enough.

With three motors the belt has to stretch around the motors and the platter. With in reason I don't know if some extra belt stretching is an issue on its own or not but I would not want to go too far. But if the over all set up places too much horizontal force on the platter I think that would be a bad thing.
milimetr OP
139 posts
 
Thanks for clarification. However with AC-3 setup I have a motors as close to the plinch as possible to avoid touching motors to the plinth. So cannot reduce belt tension further using this given belt length.
downunder
1,329 posts
 
Milimetr

The belt is a different length for the ac1 and ac3. Sometimes I swap to 1 motor and change the belt.

You do have separate belts?
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