Atmasphere thanks for that info. Something is not clear to me. Maybe it's just me. Did you actually permanently mount a tonearm to the lathe ?
You said.
What we discovered is that the arm mounted on the pillar was giving us more noise than the same lacquer played back on a Technics 1200 sitting nearby.
Just so I understand, you attempted this in order to make your business of cutting and testing playback more effective and efficient. I can understand that, and you have discussed the Technics SL1200 with Grado cart in another thread. Now you said in regards to the tonearm mounted in the pillar next to the lathe.
IOW, it was not suitable for actually telling if our cut was truly silent, set up in this fashion.
So it generated noise, which in your line of work is how you pass or fail the discs that were cut. This is my understanding of what you are saying.
But then you said.
By coupling the arm directly to the plinth in which the platter bearings reside the issue was solved.
So. Are you referring here to playing the cut disc back on the nearby technics sl1200 in your work environment ? or did you actually mount the tonearm that was on the pillar directly to the lathe plinth?
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btw - thanks for the great information on my question about the angle of the disc cut.
Pani (OP) sorry, but if I may digress for a moment...
It is consistent with the info I have received from talking with people that do this work over the years. The very important part of the information to me, is that the angle of the cut varies. The angle that the cutterhead is placed at when a disc is cut, results in an included angle in the final disc. This included angle must be duplicated with the reproducing stylus or distortion will result. I think everyone is ok with this right statement ..right ?
Now Halcro (Henry) said
I'm not sure that the cutting process tests can be transposed to the playback field.
The angle of the cut varying on the cut disc; applies directly to playback of the actual records we buy.
Let us think about something.
We all own multiple copies of favorite pressings. Have you ever noticed how lps from the same era, country and plant can sound different ?
The stylus life as Atmasphere said is based in hours. And when it is replaced it is never set up exactly the same again. And the cutting stylus puts that included angle in the disc. If that angle is not duplicated on the records we buy, you will get something on playback that is different than what was originally cut. And it can vary with record. So to those that like to use a USB microscope to set up VTA/SRA .....? thats another thread discussion. It does bring up importance of correct VTA on the fly (imo).
So what ....
To me it means the skill of the lathe operator is very important. Imagine that same music being done on different brand lathes, different countries, different eras....
All the great engineering work that was done to capture the original recording on tape or file; can be lost if the guy/gal doing the cutting is still learning how to do it. Sorry to ramble. Fascinating stuff.