dimkasta
11-03-2017, 18:52
A few months back I got very nice results by damping the PCB on my CD player with some cork, so I thought why not try something similar with the SL1200 as well. The motor itself is soldered on the PCB so it should make a difference.
I did some initial tests with some plain bottle corks I got from the supermarket. I just cut them in 8.5-9mm pieces and stuck them below the motor. Just be careful not to cut them too long because they will push the pcb up too much, slightly changing the height to which the motor sits in relation to the magnet on the platter. Cut them so that they touch the pcb firmly, but also allow it to touch the metal stop on the bearing.
I also designed a ring to hug the bearing body, while at the same time couple the pcb to the chassis. The issue here is that to get tight tolerances the cost goes up very fast, and I have to experiment on what works best. Coupling everything together tightly with mass? Or just lock them with a damping material to keep them innert and let the bearing and its body do all the actual work to transfer vibrations to the chassis.
I have made some draft parts on acrylic, and I am working on making a few on cast aluminum to see what works best. To reduce tollerances and tightly couple the materials I intend to try metal, cork and wax.
For now, I fitted the acrylic dry for a quick test, and results are VERY promising.
I also want to try a combination with the corks (because a hard material will never tightly fit right at the solder points of the motor)
And I also want to try to screw the entire thing down to the chassis using the holes at the metal can that holds the FG generator coil.
Here are a few photos dry fitting the ring on my extra whiskey/beer splashed donor turntable.
19676
19677
19678
I did some initial tests with some plain bottle corks I got from the supermarket. I just cut them in 8.5-9mm pieces and stuck them below the motor. Just be careful not to cut them too long because they will push the pcb up too much, slightly changing the height to which the motor sits in relation to the magnet on the platter. Cut them so that they touch the pcb firmly, but also allow it to touch the metal stop on the bearing.
I also designed a ring to hug the bearing body, while at the same time couple the pcb to the chassis. The issue here is that to get tight tolerances the cost goes up very fast, and I have to experiment on what works best. Coupling everything together tightly with mass? Or just lock them with a damping material to keep them innert and let the bearing and its body do all the actual work to transfer vibrations to the chassis.
I have made some draft parts on acrylic, and I am working on making a few on cast aluminum to see what works best. To reduce tollerances and tightly couple the materials I intend to try metal, cork and wax.
For now, I fitted the acrylic dry for a quick test, and results are VERY promising.
I also want to try a combination with the corks (because a hard material will never tightly fit right at the solder points of the motor)
And I also want to try to screw the entire thing down to the chassis using the holes at the metal can that holds the FG generator coil.
Here are a few photos dry fitting the ring on my extra whiskey/beer splashed donor turntable.
19676
19677
19678