Has anyone else noticed top end distortion creaping in after pressing?
I mean I cut a reference disc with no distortion, then cut a lacquer with the same settings but the pressings came back with a small amount of added distortion in the tops.
Distortion after Pressing
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Re: Distortion after Pressing
It's rare but it has happened.
It's possible that the lacquer refs had more springback than the master lacquers. (creating a difference in top end and hence hi-freq tracking distortion on the pressing)
-Also it's possible that having played the lacquer ref could round or soften the sharp edges of a hi frequency groove.
It's possible that the lacquer refs had more springback than the master lacquers. (creating a difference in top end and hence hi-freq tracking distortion on the pressing)
-Also it's possible that having played the lacquer ref could round or soften the sharp edges of a hi frequency groove.
Re: Distortion after Pressing
Yes, we noticed it a lot, last year before any pressings were made. Transient distortion on the mother that isn't on the identically-cut ref happens when the electroforming is flawed. We arrived at this realization when we started having the 'pulled' master lacquers sent back from the lab, along with the mothers, so that we could QC both before any recuts were sent out and before any vinyl was heated. (Obviously, if you detect noise in the test cut, you discard the lacquer. But if the test cuts are good, and a sacrificial master lacquer from the same lot is cut and sounds good, then problems that show up in subsequent stages of manufacturing are probably not your fault. Therefore, it will be worth playing the master cut - after it's shot - to make sure that the whole side was good.)
{One doesn't want to play the master cut before it's shot, since that would audibly attenuate treble response (even with a 1-gram balanced pickup cart) through a cruel sanding action by the pickup stylus in the soft, lacquer groove. However, after noise is detected in the mother's sturdy nickel groove, it's worth checking the lacquer's master cut groove to see if the noise was there initially, or not.}
At first we were told that there was something wrong with our 14" Transcos, however, we found that, although the mothers would have distorted transients, the 'pulled' master lacquers (meaning the master lacquers, after they had been separated from the fathers that were used to grow the noisy mothers) had no such distortion.
I made .wav files of the QC auditions and shared them with the foreman at the lab. He then began giving me free stampers until we had a good set.
The simplest way to gain access to your 'pulled' master lacquers is to 'broker' the stamper electroforming when you sell your cuts. Have the stampers and lacquers sent back to the cutting studio for QC.
- Boogie
{One doesn't want to play the master cut before it's shot, since that would audibly attenuate treble response (even with a 1-gram balanced pickup cart) through a cruel sanding action by the pickup stylus in the soft, lacquer groove. However, after noise is detected in the mother's sturdy nickel groove, it's worth checking the lacquer's master cut groove to see if the noise was there initially, or not.}
At first we were told that there was something wrong with our 14" Transcos, however, we found that, although the mothers would have distorted transients, the 'pulled' master lacquers (meaning the master lacquers, after they had been separated from the fathers that were used to grow the noisy mothers) had no such distortion.
I made .wav files of the QC auditions and shared them with the foreman at the lab. He then began giving me free stampers until we had a good set.
The simplest way to gain access to your 'pulled' master lacquers is to 'broker' the stamper electroforming when you sell your cuts. Have the stampers and lacquers sent back to the cutting studio for QC.
- Boogie