How best to eliminate LP warps

@jw944ts, having vacuum clamping, minor warps are not a problem for me. The warps I need to flatten are the major ones and they are easy to hear. Many arms will be airborne off these warps. The Schroder will track just about anything and once you are use to extreme pitch stability these warps become obvious. Minor warping may not be so obvious. My problem is that when the warps get bad enough the vacuum can not grab a seal.

@lewm , the solution is simple. Get a turntable with vacuum clamping :-)))))

And, a record flattener. 

@lewm , you hit on it. It depends on what is playing at the time. You can hear the warps on prolonged steady notes with quieter backgrounds. I think solo piano is the worst. The violin note on The Lark's Ascending would do it.  

@edcyn, you nailed it. Bowie was heavily into cocaine at the time and he was loosing it at times with severe paranoia. A lad insane.

@terry9, Yes, the Koetsu is a PITA. You do it by placing the tonearm down on a mirror with good light from both sides and your eye or a USB camera directly in front. This technique quadruples your accuracy. The stylus and it's reflection form an hourglass. You simply adjust azimuth until the hourglass stands up perfectly straight. It hardly takes any practice once you get the set up down.

This insistence on using hearing to make accurate adjustments on turntables is bordering on the absurd. Human hearing is in no way shape or form calibrated. It is like trying to use a screwdriver to remove a bolt. Wrong tool for the job. You do yourself, your stylus and your records a gross disservice by doing it that way. I do not mean to be harsh but it is important for everyone to understand this. If you insist your hearing is sufficient for the job than your ego is taller than the rest of you. You will not really hear a difference until your stylus is way out of line. 

Hey Lew, This thing really works. I plan on getting one as records warped beyond a certain point are difficult to get a seal on vacuum. Given todays shipping standards warped records are inevitable. 

@big_greg , Great find Greg and less expensive! $1150.00 @;lewm Have a look at big_greg's link. I sent them an e-mail asking about availability.

@dekay , nice thinking. The trick is there can not be any temperature differential across the record or you will make warps. Will a heating blanket and glass panes work? Sounds like a nice experiment to me!  

I just had a look at the Furutech unit. It is the same unit as the Orb with a different dress on!  The Orb is not sold here any more by license agreement. Lets see...$1150...$3270... nice racket. I'll follow @lewm to eBay.

@jw944ts , you haven't lived until you've seen your tonearm take off:-)  Any warp that can be easily seen without the record spinning will cause a noticeable pitch change if you are use to digitally stable pitch on record playback. It appears to me that given smaller warps and eccentric spindle holes we are use to a certain degree of pitch variation and our brains ignore it. If you are use to really stable pitch the irregularities become, I would not say obvious but certainly noticeable. A couple of months ago I was listening to Polini play Chopin and the piano was wavering. Sure enough the spindle hole was way off, a DGG pressing. 

@drbond , I have never measure the distance off center. I am not sure what for. Just watch your tonearm with a reference nearby. You can see the tonearm tonearm drift back and forth at 33 times per minute. That record? I'd guess it was somewhere around 0.6 mm off. The standard is within 0.2 mm. 0.6 is huge. That means the arm will drift back and forth 1.2 mm. 

@laoman , the AFI unit is a similar situation to the Furutech. My problem with the AFI is the silly stupid marketing on their web site. Temper PVC? You temper hardened metals to remove some of the brittleness. You can not harden and temper a plastic this way, utter BS. I personally won't tolerate that even if it was the best flattener out there. Furutech, as far as I have seen, does not feel the need to resort to this. To me this means their unit works so well they do not need to resort to misleading marketing. 

@terry9 , Peter Ledermann is absolutely right on that one but you can not adjust azimuth by ear. You adjust it by site which is easy to do. The best way to do it is with a mirror and a USB microscope but, I did it by naked eye for decades. The stylus has to sit symmetrically in the groove or you can accelerate both stylus and record wear. The message here is do not waste your money on a Fozgometer save and buy a USB microscope. For $300 you can get a really nice one.

@edcyn , I also share your enthusiasm for digital sources but for the majority of my life I have endeavored to improve LP playback and until I get to a point where little room for improvement is left I will continue to face the challenge. Digital is just digital, there is no challenge.  There is also no amazement. That a trench dragged along under a rock can sound as good as it does is amazing and as a collectable albums beat files by a long shot. IMHO the absolute best sound comes from properly mastered high res digital files. They are a 45 rpm record without the noise.

@terry9, I for got to answer your question on USB microscopes! Sorry about that.

There are many hobbyist scopes out the $50 to $100 price range that are good enough for azimuth and VTA adjustment but not stylus wear. The real problem is positioning the scope so that it's aim is right and it has to be absolutely still or you will get sick watching the image. It takes a bit of creativity to get the job done. For an all around brilliant scope that you can use for stylus wear and has a staging system specifically for turntables the WallyScope is the one and only scope for the job and at last count it was $1250.00 which makes it a luxury item for most people.  

For $100 and some velcro you can get the job done for azimuth and VTA. It is also a lot of fun and USB microscopes can be very handy for a variety of jobs.

@terry9 , we already established that the two channels can have very different cross talks. (Peter Ledermann) So, by taking measurements you can assure that your stylus is digging into your records. If you want to do it this way then confirm it with a visual inspection, OK. I think it is a waste of time and money. Money that would be better spent on a USB microscope.

@melm , you are a little late with that idea but you are right on except with a good eye you are far more accurate visually than your hearing. If it make you happy.

I have made recordings with the arm set up correctly and with the stylus 2 degrees off and no one can reliably identify the right set up switching back and forth. 

@terry9 I am talking about any procedure other than direct visual adjustment of azimuth. The mission here is not to get the best sound, it is to get the stylus perfectly perpendicular to the record so that it does not dig into the vinyl. On a well made cartridge this will also give you the lowest crosstalk. If your cartridge is skewed it will not give you the lowest crosstalk but it will protect your records until you get a better cartridge. 

Perpendicularity, especially with the mirror method is easy to see and your eyes are 10 magnitudes more accurate than your ears. You do need to achieve the right set up particularly the lighting. A flashlight on either side will do it. A magnifier also helps. I use the one on the SmarTractor which is excellent.

@pryso , very true about warps and dishing. I send the dished records back. It is almost impossible to seal the convex side.

In order to hear the warp easily you have to have some steady tones like a cord held on a piano. Sine wave test records really demonstrate the effect of warps and off center spindle holes. When a turntable compensates for everything except the offset spindle hole which there is no compensating for, with vacuum clamping and rock solid speed control there is a sensation of solidity which greatly adds to the illusion. I can not tell you if this is psychological or not as I have not performed that experiment. It seems to me to be quite obvious but, out brains are powerful items and you should never write them off. 

@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 , you have to be kidding me! Both Kuzma and SME use reflex clamps. Check out their manuals.

@pindac ,what are these jet engines? The bearing wears at the thrust plate and ball. There is virtually no stress on the bushing. They never wear unless you put sand in them. 

@terry9 , now try turning the record over.

@pindac , I really wish I had some of whatever it is you are smoking. I wish I had that kind of ...energy.