Originally Posted by kraut
it should run at constant speed without WOW and FLUTTER.
Wow and flutter from the motor is often a minor issue compared to warp wow and off-center punched records
The FM distortion common in LP playback makes the 5 nSec jitter that some rant and rave about when it comes from digital gear look like a dream.
Note that flutter and wow is only a part of the story. Large and very audible amounts of FM distortion are a geometric certainty if the tone arm is not straight line tracking.
It should transmit the least amount of noise possible from the motor and bearings.
Noise from the bearings is often a minor issue compared to plating grain noise on most records.
The low and mid frequency noise levels on most LPs are 30 dB or higher than that from 16 bit digital.
The arm/cartridge should be matched so resonance frequency is below the audible spectrum
Trouble is that the effects of even a properly-placed tone arm fundamental resonance has measurable and audible effects as high as 100 Hz or more.
The arm should be stiff enough not to transmit any resonant frequencies
Secondary tone arm resonances are commonly found in even high end players when people actually try to measure them.
The cartridge should be able to reproduce as flat a FR as possible with the least amount of harmonic distortion as possible,
It is difficult or impossible to find a cartridge that lacks audible FR defects.
The cartridge noise should be a low as possible.
This isn't really cartridge noise, its usually phono preamp noise. Again, 30 dB or more higher than 16 bit digital done right.
The cartridge should be able to track as accurate as possible even passages with high modulation.
Even at modest recorded levels and frequencies LP playback has measurable nonlinear distortion that would be totally unacceptable in any other component but loudspeakers. When the levels peak, they climb like a rocket!
IMO the reason why magazines that do credible measurents of just about every other kind of component don't measure viny-related equipment is because the results are always so bad that they would impugn all of the whining over far lower amounts of distortion in every other kind of gear that they review.
Note that measurements of nonlinear distortion in speakers is almost as hard to find as any kind of representative measurements related to vinyl playback.
It appears that nobody wants to be the bearer of true but very legitimately concerning news. Vinyl has got to be the biggest sacred cow in the audio business, with speakers not all that far behind.