I'm fascinated by the idea of greater and greater speed accuracy and stability. Does anyone know how speed accurate and stable the original cutting lathes were? It seems this new GPA table may be more accurate. I now wonder if the LP was cut at a less accurate rate and if this is now or may one day be audible. It this a real or imagined concern?
I don't have an answer to your question about lathe accuracy, but know that it is genuine and active concern, along with concentricity (off-center holes) whose problems can be audible. As reproduction technology improves, some folks regard the biggest impediment facing vinyl today is the physical record itself. The last of the highly regarded VMS-70 and VMS-80 series Neumann lathes were made in the mid-1970s. A lot of techology has come down the pike since then, just like that used by GPA, which could be applied toward building a 'modern' lathe. Going farther out, I've read of the concept of creating a 3D model of a record in software that allows precise adjustment of groove placement, width and depth. I can imagine a record manufactured using such a model as the instructions into the same technology used by 3D object printers today. Such as VPI is using to make tonearms. That might mean no more lathes.
But let's suppose the average lathe used in the record making process is less accurate speed-wise than the 'table used to play the record created with it. The sonic improvements offered by the hyper accurate and stable 'table are still very audible - or so my ears tell me. I do want to learn if other listeners hear something similar or different. Are there new thresholds to be crossed in speed accuracy and stability? I kinda doubt it, but remain happy knowing there are folks out there trying to improve la vida vinyl.