You may want to use a turntable setup protractor to set the cartridge. What you have can be a symptom of improper cartridge alignment.
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Many threads already exist about this, so search, but in short:
1. tracks at end of record are frequently more compressed and thus difficult to track
2. in orchestral music they also often contain climaxes that are the most difficult to track anyway
3. make sure table and platter are 100% level, using a level tool
4. lining up by eye is not sufficient. tiny adjustments make huge differences. get a decent 2-point protractor and take the time to get it right
5. doublecheck your tracking force and VTA everytime you change the alignment. tracking force usually, but not always, needs to be at the high end of the manufacturer's recommended range. get a VTF scale to ensure accuracy and repeatability
6. repeat steps 4 and 5 over and over (because every change affects the other 2) until you have got it right
6. now repeat steps 4 and 5 by ear until you've got listenability and can track the inner grooves
If you are still getting distortion at end of record, then it was played repeatedly by someone with bad cartridge setup (possibly yourself!) and the grooves are damaged. Discard that copy of the record and get yourself a new one.
Also, make sure you buy mint records and have a record cleaning setup of some kind (I recommend Disc Doctor; others recommend other systems). Dirt however is an unlikely candidate here if you're only experiencing end-of-side problems.
Just to add to an earlier post:
The record spins at a constant angular velocity (33 and a third RPM for LPs). The linear velocity of the record at a particular point with respect to the stylus is equal to the effective radius of that point (i.e. the distance from the record center to that point) multiplied by the angular velocity of the record.
The linear velocity changes constantly as the stylus spirals inward. It is largest at the outside of the record and drops toward the center.
The higher the linear velocity, the better the sound. Thus the inner part of the record will always sound worse thsn the outer part. Many audiophile recordings intentionally avoid using the inner third of the record to achieve better audio quality.
Are you noticing an overall drop in quality, or something more severe such as mistracking? If the former, then welcome to the world of vinyl. If the latter then recheck tour setup.
This phenomenon is well known and is usually called "inner groove distortion" (clever, huh?!). It exists not because of compression - which would actually tend to relieve the problem - but because the progressive shortening of inner grooves requires that modulations representing any particular frequency get progressively smaller and more closely spaced. (IOW, linear groove speed past the stylus steadily decreases, so smaller/tighter groove modulations are required to move the stylus at any given frequency.)
Since your stylus can't get smaller, nor your cartridge suspension more compliant, tracking these progressively smaller and tighter modulations becomes progressively more difficult. The first audible signs will be distortion and/or disappearance of the highest frequencies. The greater the amplitude, the worse the problem. As the stylus tracks further inward these problems will continue to move down the frequency scale and incorporate more of the midrange.
If all of the excellent suggestions above don't help, the solution might be a different cartridge. Some are definitely better than others.