2. analog
  3. 177351-1662

How best to eliminate LP warps

I own about 2500 LPs, and I like to think they're flat.  Furthermore, I espoused the view that warped LPs ought to be discarded.  But lately I have found 2 or 3 of my LPs that do have warps but sound too good and are too precious for the music recorded on them to throw away.  So I am in the market for ideas on how to remove warps.  I am aware that there was a device on the market that looked like a large waffle maker, to be used for warp removal.  I think Furutech made it, but I never see it advertised these days.  I am also aware of the DIY method of placing an LP between two glass plates and heating the ensemble.  The question there would be how hot and for how long?  Any suggestions are welcome, especially opinions on the efficacy of the Furutech.  Thanks.  Please no comments on vacuum hold down; I think it's a great idea but none of my five turntables has that feature.

lewm
pryso
1,929 posts
 

@terry9, yes something similar can work for some dished records.  However I had a Kuzma table  which utilized a washer (diameter no more than a quarter) and threaded clamp and I only had partial success with that.

But you mention a thin beveled washer over most of the label.  I've never seen one like that.  To me, to be effective it seems the clamp must have a greater diameter than the washer for it to be able to push downward on an unsupported portion of the LP.  So I don't understand how a washer that large could work?

slaw's avatar
slaw
21,541 posts
 

I’d like to see a picture of that washer. It’s shape/effect makes sense to me as long as the end of a record ( inner grooves) makes good contact.

pindac's avatar
pindac
2,864 posts
 

@drbond In relation to your inquiry about eccentric rotation, the Link might prove to be latest commercial device on offer to confirm the amount of Off Axis eccentricity being produced.

It would be good to know if this device is also able to measure the Spindle being rotated in a Off Axis Rotation.

 https://ds-audio-w.biz/products/563/?fbclid=IwAR041VevFGPZEx1e_igdoMNhhEUbOFKiQvBaK3ktZM-ocM63_X6sAnehJ98  

mijostyn's avatar
mijostyn
8,570 posts
 

@terry9 The washer goes under the record. Reflex clamping will not flatten a dished record when the convex side is down.

@pindac , Interesting device. Eccentric spindle holes are certainly a common problem. The industry standard is within 0.2mm of dead center.  It would be very difficult to make an off center spindle as the spindle is usually machined as part of the bearing. Laths do not make items off-center. With a sine wave you can hear and see off center (on a scope) easily. Complex music is another thing. It would be interesting to see how far off the hole would have to be before it became obvious with music. What to cut up some records?

terry9
2,338 posts
 

@slaw Don’t have a picture yet. I’m still finishing the DIY air bearing tonearm - just installed the Koetsu, and it sounds even better than before. My platter has a 0.008" recess for the label, so to implement the reflex clamp I needed a washer to correct that as well. My first attempt is a 3" diameter black Delrin disk, whose outermost 0.25" is 0.008" thick to correct for the recess. The disk then rises to 0.055" thick at the spindle. Flat side is down, obviously. Design is after "Niffy" at DIY Audio.

@mijostyn Your intuition is flawed. It works as indicated.

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