Transrotor Fat bob tmd reference

The Fat Bob Reference is equipped with Transrotor bearing technology, which means that the engineers who designed this model are very competent indeed. This is to be expected, after all, Transrotor has been doing this for over 40 years, but it's still a serious thought and effort on how to drive a high mass chainring.

I will do my best to break it down, as it is not easy to explain and make sense of it. I had to look closely at the physical parts of the turntable myself, and draw information from several online sources to get a clear picture of the situation:

The inverted magnetic bearing is on a substantial steel shaft, which protrudes from the base/plinth/arm assembly on which the main platter and sub-platter are mounted.

It is called inverted because on most turntables (Rega for example) the shaft points down from the sub-platter and rotates on a bearing in the shaft housing. The Fat Bob has a two-part ceramic bearing, with a ball bearing mounted in a cup-shaped cavity at the top of the shaft, which rotates in the sub-platter well itself. Now imagine a spiral groove running up and down the inside of the bearing shaft; this forces oil to constantly circulate, saturating and lubricating the shaft and bearing.

So, when this huge plate is fitted, one would think that the bearing connects to its seat in the shaft and that is where the friction point is. No wonder so much oil is needed in the shaft.

The bearing never touches - there is a real gap between the ball bearing and the seat - because it is an inverted magnetic bearing.
Super-strong magnets in the bearing/sub-platter assembly mate with their oppositely-loaded partners in the platter: the load is so strong that when the sub-platter turns, it is this magnetic lock that turns the platter - there is no physical connection between the motor drive belt and the platter.

One of the net effects of this black magic is that it is supposed to greatly reduce wow and flutter.

One of the net effects to my ears was an incredibly smooth, powerful and solid sound that the music could build on.
The power supply is very stable and can be placed anywhere as long as the power cord reaches the motor. It has a large polished aluminium knob for selecting 33-1/3 and 45 RPM, as well as an On/Off rocker switch on the rear panel. It also has two recessed adjustment screws for fine control of pitch at any speed.

The fit and finish of each component is absolutely impeccable and well thought out. The photos capture this quality, but it's when you physically touch the turntable, or try to move it, that you can appreciate the world-class workmanship

HIGHLIGHTS

    TMD bearing version
    solid aluminium chassis
    heavy aluminium platter, approx. 15 kg