Skeptoid: Digital vs Vinyl
Reply #39 – 2012-04-06 07:44:56
[Having said that, playing vinyl twice inside of a short period of time is bad for the vinyl and you will not get the same signal off the record. I responded to this specific claim. He claims, he has to supply the proof. Not the other way round. ... Somewhere in my (paper) files I have a copy of a study performed in the early 80s that examined what happens to a played disc. It included observations on how long a groove takes to recover from the elastic deformation caused by playing. I can't remember the exact numbers, but I was surprised by how long it took. I haven't found the article yet, but while I was looking I did find something on wet playing:... I playback records wet and remove the residual moisture after playback. I found a report from a seminar presented by the Discwasher company, summarising the results of some two years of research into the interaction between vinyl disc records and pickup cartridges. Their research naturally included the effects of cleaning fluid. " ... In one test, a 4 Khz test record was treated with de-ionised water and it was noted that there was a small increase in distortion; but after it had dried the distortion shot up by 20 to 25 dB - and similar results were had with an intermodulation distortion test record. Re-wetting the records brought the idstortion down again, but not to the original levels. Thus wet playing causes a permanent increase in harmonic and IM distortion. For verification, records were wetted but not played and the eventual conclusion was that the water reacted with chemicals in the vinyl, causing a "puckering" effect. A more detailed explanation came from Dr. Bruce Maier (Discwasher principal), who put most of the blame onto stabilisers that are put into the record for anti-static and other reasons. One of these compounds is a co-polymer resin, vinyl acetate. This dissolves in water, but when it re-forms it makes hard ridges and bumps. I quote Dr. Maier: 'We postulated that acetic acid would be formed in this reaction, so we played the record twice - if the acid was there we thought it needed stirring before we could measure it. Lo and behold, the pH had increased 20 to 30 times. Once that acid is formed, it starts an automatic hydrolysis of the record surface. Now the record dries and spectral analysis reveals that these interfacial changes on the surface of the record cause a permanent puckering.'" I'll keep looking for the deformation article. Only 11 folders to go...