[FONT=arial, sans-serif]Myles, what I appreciate about the SMARTractor is the attention to detail and the overall precision of the device. The SMARTractor is a triangulation type alignment tool. Specifically, it includes three differently sized spindle inserts (7.1mm, 7.15mm, 7.2mm) to more precisely center the tool to the center of the platter. Without this feature, the tool may fit your particular turntable spindle, or it may too big or not fit at all. Most tools error on the side of too big to accommodate as many models as possible. If that starting point isn't precise, then one cannot be confident that the resulting alignment will be correct. I also appreciate the use of a mirrored platform, which allows for positioning your eye to try and eliminate parallax when viewing the cartridge and alignment grid. The tool includes 5 different alignment grids to experiment with (Baerwald/Loefgren A IEC, Baerwald/Loefgren A DIN, Loefgren B IEC, Loefgren B DIN, and UNI-DIN), so regardless of your particular requirements, the tool can accommodate what you want to try. There is also a very precise spindle to pivot measurement aspect to the tool as well that uses a Vernier type scale to 5/100mm accuracy. The importance of this, is so that you can measure and guarantee that the arm is mounted to achieve the correct spindle to pivot distance to which the geometry the arm was designed. So, if one can correctly position the arm spindle to pivot distance correctly, and also precisely center the tool around the spindle, you've gone a long way toward being able to accurately align the stylus to one of the provided alignment geometries. Caveat; given the size of the stylus we are attempting to align, the best we can hope for is precision within a compromise... We all know that, correct?? In regards to the UNI-DIN alignment, the primary difference is that it is not based on Erik Loefgren's original math, from which all the "know and public" geometries are based, e.g. Baerwald is the same alignment as Loefgren A, and Stevenson is the same math with different null points put into the equation, and most all turntable manufacturers use one of these, whether it is stated or not. I try to not say never, always, every, none, or similar absolutes, because as soon as you do...well, it doesn't end so good for you... They all behave with a "similar" characteristic in the distortion curve relative to their respective null points on the record. The UNI-DIN shows a slightly overall lower level of distortion, but the main difference is that the rate of change in the distortion levels is lower and shaped a bit differently. Our ears seem to be more sensitive to a higher rate of change rather than the absolute level of distortion, at least at this level. The actual null points of UNI-DIN are similar, but not identical, to Loefgren B IEC. I find that with UNI-DIN, lateral forces are lowered and less anti-skating force is required, so consequently azimuth is more stable across the record. All that said, depending on the geometry the arm, where UNI-DIN places the stylus tip and mass of a particular cartridge relative to what the arm will be happy with is something one has to experiment with. I find that it works quite well with the 12" VPI, for example, probably because the VPI alignment is, as far as I have been able to gauge, identical to Loefgren B IEC, which has similar null points to UNI-DIN. It's not the cheapest tool in the shed. I think it's $650 here in the US, but its the most precise I've found and it's super easy to use. Hope this helps!
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