Skeptoid: Digital vs Vinyl, Podcast casts its skeptical eye on digital audio Options

[rick.hughes]

Skeptoid: Digital vs Vinyl

[kraut]

To determine the actual deformation-force relations, complex groove impedances have been measured as a function of tracking force, groove speed, etc.

At high bearing loads complete plastic flow sets in and the needle leaves a permanent indentation track, while at lower loads the elastic deformation is predominant.

Exactly my contention versus categorical statements by those arguing from authority. Thanks.

It would be nice to know from the original paper what they found to be the tracking force where elastic deformation is dominant vs. permanent deformation.

I'm just pointing out that your belief that the practice is harmless is not supported by the facts.

I still play records wet with good results that I have owned and played back wet since the late sixties and early seventies.
If there is any harm, then it is offset by reducing problems with static, a record that is cleaned during playback etc.
It should also be mentioned that the development of heat during the playback is likely significantly reduced by a cooling agent, be it water alone or in a mix of alcohol (isoprop), thus further reducing the risk of permanent deformation.

Repeated playback (no matter what the timeframe) carries the risk of permanent damage. Obviously, records are observed to wear out with repeated play. No published evidence exists of back-to-back playback causing any more permanent damage than if repeated plays are separated by any longer period of time.

from the horses mouth itself: http://wiki.hydrogenaudio.org/index.php?ti...inyl_has_cooled

As to plasticizers in pvc:

I could not find any reference as to what plasticizers are used in PVC specifically for vinyl records. Or that Vinyl acetate was specifically used at all.

http://onlinelibrary.wiley.com/doi/10.1002...010508/abstract

Polyvinyl chloride acetate (PVCA) is a thermoplastic copolymer of vinyl chloride and vinyl acetate.[1] It is used in the manufacture of electrical insulation, of protective coverings (including garments), and of credit cards and swipe cards.

http://en.wikipedia.org/wiki/Polyvinyl_chloride_acetate

. The most common plasticizers are derivatives of phthalic acid. The materials are selected on their compatibility with the polymer, their low volatility, their low toxicity, and their cost.

http://en.wikipedia.org/wiki/Polyvinyl_chl...er_applications

Copolymers of ethylene and vinyl acetate (E-VA) of a certain composition can be used for the improvement of impact properties (elasticisation) of PVC as well as under certain conditions (grafting) for the preparation of flexible PVC (plasticisation). Products of interesting properties are prepared by blending E-VA (up to ∼ 12%) with PVC or more advantageously by grafting vinyl chloride on special E-VA types. Graft copolymerisation by the suspension method allows the synthesis of E-VA/PVC systems in all ratios (up to 80% E-VA); these polymers are compatible over the whole range in contrast to the blends.

http://onlinelibrary.wiley.com/doi/10.1002...010508/abstract

Plasticizers
It has been claimed that some plasticizers leach out of PVC products. However plasticizers do not readily migrate and leach into the environment from flexible vinyl articles because they are physically and tightly bound into the plastic as a result of the heating process used to make PVC particles.

http://en.wikipedia.org/wiki/Polyvinyl_chloride


So again the study by the so called scientists by Discwasher seems to be more than flawed and not worthy any consideration imo.

[splice]

To determine the actual deformation-force relations, complex groove impedances have been measured as a function of tracking force, groove speed, etc.

It would be nice to know from the original paper what they found to be the tracking force where elastic deformation is dominant vs. permanent deformation.

The answer is in the first quote above: It Depends.
It depends on the stylus profile, cantilever mass, suspension compliance, room temperature, "groove speed", and the actual vinyl composition.
As for figures, this area has been well studied. For example: "... we know that stylus pressure per square centimetre is on the order of tons, and that a permanent deformation of the groove is produced under static conditions. Dynamically, the values can vary by more than 12 tons/cm2, positive values causing defomation of the groove wall and negative values causing mistracking." - Jean Hiraga, 1978.
The best advice is to aim towards the maximum recommended tracking force given by the manufacturer of your stylus. Damage caused by high stylus pressure is less noticeable than damage caused by mistracking. I've found several articles in my files containing Scanning Electron Microsocope photos of groove damage caused by various mechanisms.

It should also be mentioned that the development of heat during the playback is likely significantly reduced by a cooling agent, be it water alone or in a mix of alcohol (isoprop), thus further reducing the risk of permanent deformation.

Most of the heat is produced inside the groove walls by the pressure of the stylus deforming the vinyl, not the friction of the stylus against the walls. The presence of a cooling agent has little effect.

As to plasticizers in pvc:

I could not find any reference as to what plasticizers are used in PVC specifically for vinyl records. Or that Vinyl acetate was specifically used at all.

For me, the evidence was that Discwasher found large quantities of acetic acid on the disc surface. Acetic acid is one of the precursors for vinyl acetate.
Apart from the Discwasher mention, there is:

... records are a complex chemical mixture including 85% polyvinyl chloride (PVC), 15% polyvinyl acetate (PVA), antistatic agents, dyes, stabilizers (heavy metals such as lead stearate), modifiers and lubricants. PVA, the exact chemistry of which varies among companies, both aids in the flow of vinyl during record pressing and as a plasticizer. Plasticizers play a critical role in softening the plastic/resin.

http://www.positive-feedback.com/Issue38/lp_sleaves.htm
I recommend this discussion for those interested in optimal storage of LPs. Also Wikipedia: http://en.wikipedia.org/wiki/Vinyl_disc_records_preservation

Plasticizers
It has been claimed that some plasticizers leach out of PVC products. However plasticizers do not readily migrate and leach into the environment from flexible vinyl articles because they are physically and tightly bound into the plastic as a result of the heating process used to make PVC particles.

http://en.wikipedia.org/wiki/Polyvinyl_chloride

Proof that PVC plasticisers leach out with some alacrity is probably available in your own home, if you have plastic cables (equipment cables, mains extension cables) that have been in contact with acrylic painted surfaces. The plasticiser dissolves the paint and welds the cable and paint surface together, peeling the paint when the cable is moved. Also note that when you buy equipment with flexible leads and polystyrene packaging, the leads are packed in polythene bags. This isn't because it looks pretty, it's because the plasticisers also attack polystyrene. Finally, PVC is no longer used in "cling film" food wrappng because the plasticisers were found to leach out into the food, especially foods containing fats.

So again the study by the so called scientists by Discwasher seems to be more than flawed and not worthy any consideration imo.

I think the last word of your sentence is the operative one. Facts are less partial.