From: utzoo!decvax!harpo!npoiv!npois!houxm!houxa!houxi!whuxk!wjm Newsgroups: net.audio Title: warped records Article-I.D.: whuxk.146 Posted: Tue Feb 22 11:23:24 1983 Received: Wed Feb 23 03:49:19 1983 I agree, the quality of records put out by record companies, especially the American ones, is a disgrace. I've just had to take a copy of "Swan Lake" back several times due to Angel's lack of quality control - the records were visibly scratched when I opened the package. Fortunately, most of the larger NYC record stores are pretty decent about returns - they'll exchange it within a week or 10 days, as long as you keep the sales slip. As for dewarping records, there are several counter-measures that work: 1. The vacuum pump approach mentioned above. It is used by Luxman and in a few other high end turntables, and is available in an ~$300 accessory unit (I don't remember who made it). It works well but isn't cheap. 2. The edge weight made by Kenwood. Again it works well but will set you back about $150. 3. Changing your turntable. Some turntables and arms and cartridges are less suceptable to mistracking due to warped records than others. My present one (a Denon with an Adcom cartridge) is quite good this way although my old Philips was terrible. This has to do with arm resonance frequencies and the amount of VTF used. Although conventional wisdom says lower VTF is better, if one goes too low one causes more damage to records due to mistracking than would be due to wear at 1.5 - 1.75 grams (which is the recommended VTF for many higher end moving coil cartridges with hypereliptical, Shibata, Van der Hul, etc stylii). Actually, with this type of stylus, the contact area is larger than on an elliptical tip, so the pressure on the groove is actually less. 4. Cook the record as described above. Two caveats - make sure the glass panes are clean - or you'll cook the dirt into the record and two - don't overheat or you'll have a lot of expensive molten vinyl. Cheers and good luck. Maybe if we keep returning the bad ones - and if you dont get satisfaction from your local store gripe to the record companies, they'll do something about it. Bill Mitchell