So what is zero offset pure straight tonearm and why it is good ?

As you can see in pictures, this tonearm does not have offset angle, the offset angle is 0. Generally, traditional tonearm has offset angle from 11 to 15 degree and to make tracking error smaller but the big problem is the force on the both side of stylus is difference.

When a record is played pianissimo, friction is small, and when it is played fortissimo, friction is large. At this time, the record needle is pulled forward and extend. This force causes the cantilever with an offset angle to rotate counterclockwise when viewed from above, so the base of the cantilever moves toward the inner circumference.

So, depending on the volume of the music, the record needle moves back and forth, and at the same time, the cartridge body moves left and right, which causes the time axis to fluctuate. In other words, the sound is delayed and dulled. it can be seen from the jitter in digital audio, the fluctuation of the time axis in audio is very important. The experience of CAPRICE, which developed an ultra-low jitter clock and applied it to a DAC that was very well received, came in handy.

The tonearm has inertia, so it is difficult to move at fast cycles, but it moves at slow cycles. In fact, the sound of bass instruments is very different, and without the offset angle, the unwavering bass is so powerful that it seems to crawl along the ground. If you like bass, you will not be able to resist it. There is no ambiguity, so it seems like a master tape or a well-made digital device.

The traditional tonearm design purpose is making tracking error on tonearm is as small as possible. However, what was more important was the time fluctuation caused by side force fluctuations. This highlighted the fact that this was causing a problem far greater than tracking error.
In the pure straight tonearm, the needle and cantilever of the cartridge overlap in a straight line with the center line, and always maintain a stable balance during tracing. In addition, because the overhang is negative, the arm effective length can be shortened by more than 30 mm, realizing high rigidity and low resonance.

The first idea of making pure straight tonearm came from Yamaha, they manufactured the legend tonearm call YSA-2, which is very rare and hard to get nowadays.

This tonearm was modified from the Audio craft AC-3000MC tonearm, the armward is longer than original long version of AC-4000. The effective length is 282mm. Audio craft is really good tonearm with oil damp mechanism, but it is even better after modifying it become pure straight tonearm. The longer version make tracking error smaller and sound is more detail. The sound is more clearly, the bass sound is much better, low distortion and rich.

The arm pipe was made from carbon fiber, the distance from center of turntable to tonearm pivot is 300mm but overhang is changed from 15mm to -20mm.