HiFi & Records - Germany, Oct 2005

by Helmut Rohrwild

* translated from review

text originally in German

TW Acustic Raven AC

Thomas Woschnik belongs to the group of those analog-enthusiasts who have never really been satisfied with what is offered on the market. So a few years ago he decided to make his idea of what a turntable should be a reality – on his own and uninfluenced by any kind of trends. He focused his attention on perfect rotation, the basis for duration. The result is a massive turntable with a strong motor and extremely precise control.

When he offered me one for a test review, I agreed immediately. Until then I had only heard about these turntables in various online forums. But the rumors about them promised a most-interesting analog encounter. We chose the Raven AC for the test, which in Woschnick's opinion is very similar to the top-of-the-line Falcon. Though the Falcon is intended for play with only one arm, the Raven allows for up to four – which for me was an important factor. The question of the arm mounts was also quickly settled: a bronze mount for my Schröder Reference, made out of synthetic materials for the VPI JMW 12.5, plus an additional SME mount.

The Raven AC was delivered in two sturdy wooden boxes. One box contained only the base, the other the turntable, the motor, the control unit, and accessories. The base's weight is disguised by an elegant, wavy design. The turntable is made of a black synthetic material, which Woschnick developed himself. He reveals that the basic material is Delrin, but the other materials that make up the compound remain his secret. He also relates that the surface, for acoustic reasons, is not completely smooth (which would be cheaper) and that the base, therefore, absorbs resonance.

Thick stainless steel cylinders are located at the four corners of the turntable. The front two contain rubber feet that are adjustable from underneath via fine threads (which lock the setting into place). On the back cylinders the arm mounts are tightly attached with M10 screws (which lend additional centering and more contact surface). The third foot is located in the middle back; in this way the player is easily put into balance.

On the base a high-quality stainless steel disc is screwed on, in which the bearing pin is placed. It is two centimeters thick, as is a screw which stabilizes it from underneath. Any search for a ball bearing will be in vain, as TW-Acustic diverges here as well, also with sound mechanical reasoning: The top of the pin is round and connects with a Teflon disc at the base. They then work together to achieve, through the relatively large surface, considerably less pressure than a ball bearing. The amount of friction here should be at least as small as the various ball bearing options. The long running time of the table proves that, without a doubt, this is the case (a perfectly-fitting bearing is, of course, also important).

Now we've come to the platter. Before it is assembled, the base should be put in its place and assembled. Each part that is added adds considerable weight and at some point the machine can no longer be lifted. The entire Raven AC weighs in at 50 kilograms.

Now on to the second box. The motor is placed next to the turntable, the distance between the platter and motor axles being 33-34 centimeters. The control unit should be placed so that the on-off button as well as the speed settings can be reached without difficulty. A reasonably long cord allows for sufficient distance to the turntable.

Then come the arm mounts. The standard arm mount is made of bronze and weighs a full two kilos. It's made for almost every arm; you have a choice of either synthetic or bronze arm mounts. I myself have installed my Sony PUA 286 and the Dynavector DV 505 on the SME mount with use of an adaptor. In this way I could achieve the four-arm ability of the Raven. As I've said before, I'm of the opinion that such an expense for a product of this category is justified.

Since the Raven AC has an inverted bearing, the bearing and the previously-mentioned Teflon disc are located in the platter. Halfway up the bearing is a depression that serves as an oil plate that collects oil that is transported via a flattened surface on the pin. A simple mechanical engineering solution. Before the plate is assembled, a couple of drops of oil are placed on top of the pin and in the bearing; then the plate can be carefully put into place. Then the flat belt is attached, with the rough side on the inside. In reply to my question about how one can today find mass-produced belts in micro-sized pieces, Woschnick answers: "That only works when there's a hifi-maniac involved." Not many small firms are quite so lucky.

The motor has very good torque. With custom building the motor is capable of extremely precise steering through a quartz-controlled micro-controller. There is a maximum precision error of only two nanoseconds per minute, which is extremely minimal and difficult to imagine, especially in contrast to one second in some turntables. Only Direct Drive and the SME 10 have proved capable of that.

Now the turntable must be balanced vertically, because of the slightly-rounded pulley, which allows for the belt to continue to run cleanly and quietly in the middle. Finally, the speed is finely adjusted and set with a calibrator disc – then it's finally time to indulge in a little pleasure.