Motor Vibrations

I'm in the midst of tuning/upgrading a Well Tempered Classic. The original AC motor has a significant vibration, so I've been experimenting with the Origin Live DC motor and power supply. The OL motor vibrates fairly significantly, too, enough to be transmitted through the belt,platter and into the cartridge. I can also clearly feel the vibration in the belt whien I lightly touch it. I've experimented with different belts (the original rubber plus silk and nylon cords and dental floss) and found that the only way to reduce the vibration tranmitted to the cartridge is to loosen the belt tension to the point that there starts to be some "wow". Do all of you with DC motors experience vibration? If so, how much?

I suspect that I may have a bad motor, but the dealer tells me that the motors do vibrate to some degree. I could change over to Well Tempered's new AC motor which has some circuitry that is supposed to minimize vibration, cogging, etc. (See their website for details)

Any thoughts, suggestions, questions are welcomed.

Thanks
Jim