Pimples on the grooves.

[sunder]

Hello friends, what would be the sound effect upon impact of pimples on the grooves of vinyl when playing? Is it harmful to stylus? Can we play the records with pimples? Why these pimples appear on the grooves? Is this because of weather condition? What are the cartridges suitable to play with those records having pimples? Please share your experiences and suggestions. Thank you.
Regards,
sunder.

 

[Saket]

Hello friends, what would be the sound effect upon impact of pimples on the grooves of vinyl when playing? Is it harmful to stylus? Can we play the records with pimples? Why these pimples appear on the grooves? Is this because of weather condition? What are the cartridges suitable to play with those records having pimples? Please share your experiences and suggestions. Thank you.
Regards,
sunder.

Sunder,

I have a disc which has that 'pimple'. Though I do no play that lp too often, but avoid the area if the LP is played at all; I can say that probably you won't find anything better than Shure M44-7 to track these records. My M44-7 plays that record as any other record. Though, I avoid playing LPs with too much warp and such pimples as the suspension on the cartridge will take a beating.

My OEM Technics cartridge (or EEI...not sure what it is) jumps all over the place on such records.

Regards,
Saket

 

[reubensm]

Sunder,

I have a disc which has that 'pimple'. Though I do no play that lp too often, but avoid the area if the LP is played at all; I can say that probably you won't find anything better than Shure M44-7 to track these records. My M44-7 plays that record as any other record. Though, I avoid playing LPs with too much warp and such pimples as the suspension on the cartridge will take a good beating.

My OEM Technics cartridge (or EEI...not sure what it is) jumps all over the place on such records.

Regards,
Saket

+1 to that. My M44-7 plays these with ease. But I've noticed that the stylus cantilever is under undue stress while scaling the pimple. My other carts cannot play pimpled records.

Some LP's are a "sandwich" of plastic (not normal vinyl), carboard, and plastic. The pimples appear when moisture invades the edge or center hole and causes a bump in the middle cardboard layer. In some cases the "grooves" of plastic come off both sides leaving the owner of the LP with a 12" disc of carboard and two very floppy 12" plastic discs with the grooves on them. In cases of LP records made from solid vinyl, the pimples are factory defects, which I believe are a combination of not enough dwell-time in the press and/or insufficent moulding release agent, so the pimples had stuck to the stampers. Damaged stampers are another possible cause. My 2 cents.

 

[sunder]

+1 to that. My M44-7 plays these with ease. But I've noticed that the stylus cantilever is under undue stress while scaling the pimple. My other carts cannot play pimpled records.

Some LP's are a "sandwich" of plastic (not normal vinyl), carboard, and plastic. The pimples appear when moisture invades the edge or center hole and causes a bump in the middle cardboard layer. In some cases the "grooves" of plastic come off both sides leaving the owner of the LP with a 12" disc of carboard and two very floppy 12" plastic discs with the grooves on them. In cases of LP records made from solid vinyl, the pimples are factory defects, which I believe are a combination of not enough dwell-time in the press and/or insufficent moulding release agent, so the pimples had stuck to the stampers. Damaged stampers are another possible cause. My 2 cents.

Thank you Saket, reubensm. Unfortunately the pimples appeared on the LPs which we delight in that ! Only Indian pressed vinyls mostly have pimples. As reuben said, this is the defective of quality control.
Regards,
sunder.

 

[bhaskarcan]

.................
.......................... In cases of LP records made from solid vinyl, the pimples are factory defects, which I believe are a combination of not enough dwell-time in the press and/or insufficent moulding release agent, so the pimples had stuck to the stampers. Damaged stampers are another possible cause. My 2 cents.

+1 reubensm. In case of vinyl records it's manufacturing defect. Without going into the details of record making, I would just like to add that after stamping the vinyl record goes through a cooling process. And in this process it's also put in cold water. If it's done(putting in water) b4 the record reaches a particular temp. these dimples are caused. Hence this a case of some particular record and not the full batch.

I may say these records are cases like wrongly printed postal stamps and should be preserved.......

Bhaskar