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-   -   Vinyl Flat Record Flattener (https://www.diyaudio.com/forums/analogue-source/195861-vinyl-flat-record-flattener.html)

wintermute 5th September 2011 02:40 AM

I had a couple of LP's that I wanted to try and unwarp, never got around to it. But my plan was to put them between a couple of flat bits of wood (probably masonite at the time) with some weight on and sit it in the sun.

Tony.

planet10 5th September 2011 03:17 AM

I use a similar technique for making dustcovers

https://www.diyaudio.com/forums/atta...dust-cover.jpg

dave

Ron E 5th September 2011 04:36 AM

Quote:

Originally Posted by planet10 (https://www.diyaudio.com/forums/analogue-source/195861-vinyl-flat-record-flattener-post2698074.html#post2698074)
I use a similar technique for making dustcovers

I can see why you need a dust cover ;)

robmil 25th September 2011 06:25 AM

Flattening a warped record can only work if the warp is of a certain curve.

imagine this... take a peice of plastic and heat it up - it stretches.
The grooves in a warped record are in the 'wrong place' in time because the groove has been stretched. So one revolution will now take longer than normal.

When the stylus starts the travel up the warp, it HAS TO take a slightly longer time to reach the crest/peak of the warp than if the record were flat. If the warp was 1cm long this would mean the record has increased in length by 1cm.
That extra time cannot be decreased.

Flattening a warped record won't do anything because the groove length has already been distorted and that cannot be corrected in time.

It is cheaper to buy a replacement copy.

Straight Tracker 25th September 2011 07:42 AM

Hello robmil
 
Quote:

Originally Posted by robmil (https://www.diyaudio.com/forums/analogue-source/195861-vinyl-flat-record-flattener-post2723155.html#post2723155)
The grooves in a warped record are in the 'wrong place' in time because the groove has been stretched. So one revolution will now take longer than normal.

When the stylus starts the travel up the warp, it HAS TO take a slightly longer time to reach the crest/peak of the warp than if the record were flat.

The RPM of a record will always be the same as that of the turntable regardless of wether it is flat or warped.

It does not take the stylus more time to reach the crest of a warp. What happens is, that the groove to stylus velocity increases during the warp, resulting in what is known as "warp wow"

Sincerely,

Ralf

robmil 25th September 2011 08:56 AM

Hi Ralf

I sort of get you but if you increase a length of string, it is now longer. There is no difference with vinyl, it is like plastic and a warp is a stretched part of the vinyl therefore it 'has to' take longer to travel the extra distance.

All you need to do is measure the circumference of a flat section of vinyl in its flat state, then heat it up to introduce a warp. Now measure the circumference - it is longer, it is link chewing gum.

Now imagine the groove walls. These have also stretched. By flattening the vinyl all you are doing is flattening a completely distorted groove wall. You can't flatten to its original state, that is impossible on this planet.

This is exactly why it is cheaper to buy a replacement vinyl record.

Straight Tracker 25th September 2011 09:49 AM

Hello robmil
 
I guess a good example of the point I am trying to make, would be to think of an airplane wing. The air moving over the top of the wing has to move a greater distance, hence faster, than the air that moves under the wing in order for both streams of air to get to the rear of the wing at the same time.

The same is true for the stylus when it encounters a warp. If the RPM of the record is constant, the stylus has to get from the beginning of the warp to the end of the warp in the same time that it would take if there were no warp. That means the relative speed between the groove and the stylus has to increase.

I agree, I would not waste my time fixing warped records.

Anyway, my SME tonearm which I purchased in the seventies, plays warped records without any problems.

Sincerely,

Ralf

robmil 25th September 2011 11:26 AM

Hi Ralf

If the RPM of the record is constant, the stylus has to get from the beginning of the warp to the end of the warp in the same time that it would take if there were no warp. That means the relative speed between the groove and the stylus has to increase.

That is an interesting statement because to cover the extra distance you would have to increase RPM. The warp actually increases distance and there is no other way to cover the extra distance in the same time than increase RPM.

Therefore flattening a warped record is useless. You will still end up with a distorted groove.

Yes, I use a TW Acustic 10.5" tonearm and although it can track a warped record with no problem, the wow and increase in non-linear artifact means it is pointless playing a warped record.

lindex 26th January 2012 04:58 AM

Hello everybody, came across this thread when looking for DIY de-warping methods for vinyl records. It seems like a lot of people are using home made variations of the kinds of presses you can buy, which in my mind makes sense ~$80 USD seems a lot for a _very_ simple device. I had the idea of maybe making a simple press with some 1/8 inch or 1/4 inch thick glass panes and using a heat gun? I'm a bit scared of getting records anywhere near my oven and though that a heat gun would work well. The advantage of the glass press being that it would transfer the heat well to the record, something similar to simulating leaving it out in the sun on a hot day, but in a more controllable manner.

I would of course do a full cleaning before trying this, I was thinking of using the "wood glue" method that I've seen documented online.

What do you guys think of the glass press idea? And/or, have any of you tried the "wood glue" cleaning, or would you recommend something else?

h_a 26th January 2012 05:46 PM

Well, from what I see these methods need a bit of experimenting for any practical results, so if you're willing to risc a few of your records you could try and report back.

Otherwise it is my impression that ready made devices have only one major advantage, namely being debugged and fairly reliable.

Hannes


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