dab@sri-unix (10/25/82)
Does anyone have advice on how to "unwarp" warped records. Does piling weighty books over a record help??? Is the cause hopeless??? Thanks for any advice David Basin (teklabs!reed!dab)
pag@sri-unix (10/26/82)
Many years ago I had a friend who had left some new albums in the back
seat of his car on a very hot day. They ended up warping to the curve
of the seat. He was not very happy. Someone (a stero technician?)
gave the advice that you could unwarp warped records by putting the
album between some very heavy books in an oven at a very low temperature.
Feeling he had nothing to lose, my friend got a couple of Encyclopaedia
Brittanica volumes, put the albums between them, and turned the oven
on to 180 degrees. He subsequently went out. While he was out, his
mother came home, and turned the oven up to 500 to preheat it for
the evening's roast. Needless to say, this was not the treatment
the stereo technician had in mind. The result? The books were fused
together.
I don't know if the real method works or not, but back then albums
were much thicker vinyl than the "floppies" you get today.
--peter grosstiberio (10/28/82)
Here is a solar device for flattening records. Put the warped record between two pieces of clean glass and let the sun shine on the record until it is flat. This works best with black PVC records. Michael Anthony Tiberio tiberio@seismo
wjm (02/22/83)
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 Mitchelltv3b20 (02/23/83)
Does anyone own a DBX 20/20? How do you like it,
and does it perform to your expectations?
Mike Kruger
ihuxa!tv3b20jacoby (04/11/83)
I'm new to the net, so this topic may have been covered before. Does anyone have any good proven techniques for removing or reducing the severity of warps which are unfortunately so common on records today? Please reply by mail and I will summarize responses.
greg@olivej.UUCP (Greg Paley) (04/20/84)
Having a Shure V-15 IV or V won't take care of all warped records. I have one which I use as a backup for my Grace F9E, mainly for exceptionally warped records, as I generally prefer the sound of the Grace. I recently bought a set of live performance cuts by Maria Callas, one of the records of which was so warped as to defeat both the Shure and the Grace on my Sony 2251. I had bought the set in Europe and therefore couldn't easily return it. I didn't try to de-warp the record. Instead I had a friend play it on his Sony PX-600 (with the micro-processor controlled "biotracer" arm) which sailed through it with several cartridges we tried (Signet, Koetsu, and Ortofon) and had him put it on tape for me. I have read negative comments about these micro-processor controlled arms (also offered by Denon, JVC and others) and I'm not sure that I would rush out to buy one in terms of the general sound quality on "normal" records. However, for these extreme cases they seem unique in their tracking abilities. - Greg Paley
crandell@ut-sally.UUCP (Jim Crandell) (04/27/84)
> Do these new microprocessor tone arms actually know enough > to vary the speed of the platter, or do they use some time shifting > circuitry? Good question, but in most cases it's academic, unless they've got the platter on about half a horse through a VERY tight drive. Some of those multi-wiggle jobs are going to require angular acceleration functions containing components at pretty nasty frequencies. Of course, you can get a similar effect by shifting the base of the arm mount, which probably would be trading one mechanical nightmare for another. At any rate, I haven't seen any that appear to do that. Time-shifting circuitry? Interesting idea. BUT, how many Real Audiophiles are going to stand still for anything that requires a SAD (let's not kid ourselves -- there's no other feasible way to do it) in the playback chain? (Unless, of course, you really want to mount your speakers on motion bases.) -- Jim Crandell, C. S. Dept., The University of Texas at Austin {ihnp4,seismo,ctvax}!ut-sally!crandell