End of lp distortion. What does it sound like

The Mint Best Tractor is the way to go; I have one. But, it's really important to use the Stevenson geometry to avoid inner groove distortion. This is a highly debated subject because on paper and in theory the Baerwald geometry produced less tracing error earlier on the LP side. However, the Stevenson alignment geometry is more modern than the Baerwald, and puts the inner null point (where the stylus is tangent to the groove) on the industry's standard inner groove limit so it produces 0 tracing error where the grooves are the smallest, slowest, and most suseptible to AUDIBLE distortion. This is a case where Baerwald is better in theory and on paper, but in practice Stevenson is better. The increased tracing error induced by the Stevenson geometry is where the grooves are longer, traveling faster, and therefore not be as audible. Yip at Mint can make you a custom protractor for your table with the Stevenson geometry and I highly recommend it. You'll have the best case scenario with his protractor and the Stevenson geometry. Not every record has grooves cut to the maximum inner groove limit, but for the ones that do, why not have them sound the best they can... which will be with the Stevenson geometry.

With 'end of LP', do you mean last track near the center of the record? This usually means you need to adjust anti-skate as skating forces are more severe in this area.

I would also help to know if the distortion is coming from both channels equally or from one channel in particular as it would also clue into anti-skate issues.

Typically, no anti-skate or as little as possible is the best, but if you are getting audible distortion, something must be done.

I doubt this is an azimuth issue. What VPI table, arm and cart are you using?

Typically it's time to replace cartridge.

Some alignment schemes are better than others at reducing end of LP mistracking. I believe the Stephenson specs are intended to address this. Not sure what protractor you are using or what specs your Mint will be based on.

I have a Scout with a new DV 20x2l so it's not worn. As for AS there is only the natural twist of the wires, I did not add any more. I have not messed with VTA or VTF yet.

Your new DV cart is a good one. Since its new, start at the upper end of the recommended tracking force - between 2.1-2.2g. See if that helps. When the mint arrives, be patient and dial it in then.

First, if your LP's and stylus are not perfectly clean, inner groove distortion (IGD) will drastically increase. As you're still relatively inexperienced with LP playback at this level I'm fairly confident that your LP's and stylus are not perfectly clean. My Audiogon buddies with many more years of experience have seen the extent I go to in this regard and they've heard the difference it makes. I've re-cleaned records of theirs and given them sonic revelations. This is job 1, the best system and setup in the world will sound like crap if crap is what it's playing. ;-)

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As to technicalities, assuming perfect LP and stylus hygiene...

Your description does sound like IGD... tormented vocals and acoustic instruments, particularly in the higher registers. IGD can make massed violins or a soprano sound like 10,000 fingernails on a chalkboard. Some LP's are more prone than others, depending on the material that's cut on the inner grooves.

The root cause of IGD is the unavoidable fact that inner grooves are shorter than outer ones. Each LP groove makes one complete revolution in the same length of time (1/333... of a minute) but since the circumference of an inner groove is shorter, the modulations that make up any given frequency are compressed more tightly than they would be on an outer groove.

It's harder for a stylus to trace these smaller, more closely spaced modulations. This is why alignment is critical. The key parameter is zenith angle (what we adjust with a protractor). For this reason, I second Dconsmack's excellent post.

Zenith angle is critical for reducing IGD, other parameters are less so. VTF, VTA, azimuth and antiskating have comparatively little impact on IGD unless badly mis-adjusted.

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The capabilities of a phono stage also have a major impact. Poorly modulated phono stages go into peak overload and/or exhibit smearing distortions that can greatly exaggerate the audibility of IGD. A better phono stage can make a huge improvement in this area.

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BTW, after a certain point IGD is unavoidable. Consider: at any given point on a groove's inward spiral there will be *some* frequency whose modulation has the same radius as the contact surface of the stylus. Adjust as we may, our stylus cannot physically trace a modulation smaller than itself, which means it cannot accurately reproduce any higher frequency than that. Instead, it will "smear" over the tops of the waveforms and produce a distorted version of the actual sound.

As the groove spirals inward and its modulations get smaller, the highest frequency any given stylus can reproduce drops lower and lower. On widely spaced outer grooves even the coarsest stylus can reproduce very high frequencies. On tight inner grooves even the finest playback stylus cannot match the smallest modulations cut by the (even finer) cutting stylus.

Nevertheless, perfect zenith alignment at the most challenging part of the record helps because it places the L and R contact patches of the stylus squarely across the groove. This keeps the difficult-to-trace higher frequencies precisely in synch across the L and R channels, reducing phase errors between them. This helps reduce the "nails-on-chalkboard" effect.

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From the above it should be obvious that the smaller the contact radius of the stylus, the less prone it will be to IGD. Line contact and micro-ridge styli are the best, conical/spherical styli the worst. Ellipticals fall in between.

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The manner in which a particular cartridge/tonearm/table combination handle stray energies leaking from the cartridge also has a major impact on how audible IGD will be. Some combos are very good together. Others are terrible. There is no set of specifications that will predict this.

The above advice is all excellent. Just let me add one thing - be careful not to get so hung up on every little thing that it kills your enjoyment of analog. I've seen this happen to a couple of people. I would try your best to get the setup right and perhaps consult with a professional if need be, but it's not going to be perfect. Sometimes, if the air is dry, as it is in winter, the record picks up a static charge and collects a lot of dust, so your stylus can be very dirty before the side is over. I happen to use Gruv-Glide to combat static, but a lot of people are agaisnt it. Just throwing it out there. Try to enjoy.

Try to ajdust VTF to the high side. It could also be bad combination for inner groove tracking arm/cart.