Automatic vs Manual
Automatic
An ‘Automatic’ turntable is one where you put the record on the platter and just press a single ‘Play’ button. The disc starts spinning, needle lifts up and moves into place on it’s own, then drops down, plays through the record and returns to the off/resting position once the side has finished.
Manual
A ‘manual’ turntable relies on you to start the spinning, move the tone arm / needle into place yourself. Once the side has finished the platter will continue to spin indefinitely - until you lift the needle up and hit the STOP button.
Verdict
I have both and prefer the ‘automatic’ functionality because the tone-arm returns at the end of the record. Regardless of which type you choose, I would also use the cue lever to start each side as the ‘Automatic’ needle drop can get a bit rough over time.
Belt Vs Direct Drive
Belt Driven
Like a bike chain, a belt-driven turntable has a rubber strap that connects the motor with the spinning platter. They take a few seconds to get up to speed and slow down. Over time the belt eventually slackens and needs to be replaced, although they are cheap and easy to repair yourself. The belt naturally dampens any vibrations or sound generated from the motor.
Direct Drive
Direct motors are attached straight to the platter. They get up to speed and slow down much faster, and most of these are digital motors that self-correct to remain at the exact speed required.
Verdict
Again, I have both. Marginal preference for the direct drive motor as it’s hard to tell when the belt starts to slacken - it took listening to a very familiar album to realise it was playing a little slower than usual. I haven’t had to replace a direct motor yet though, which looks to be expensive.
Outputs: Phono and Line
Phono
All turntables produce a very weak and unbalanced ‘phono’ signal from the stylus and cartridge. Turntables that only have a phono output will need a separate amplifier with a phono stage, or a phono pre-amp before the signal can be used by most speakers.
Line Out
The majority of modern record players have a built-in phono pre-amp. This takes the very low-level signal amplifies it to be a “line level” signal, which is strong to be used by speakers and amplifiers/receivers.
Verdict
For most modern and entry level audio equipment the Line Out signal is essential, especially for a basic “Turntable + Speakers” setup. Phono only turntables would require an additional pre-amp at the minimum, or speakers with built-in phono stage - which would limit your choice of speakers.
TERMINOLGY
Tracking Force - the downwards weight of the needle on the record. Too little and the needle can jump up when it hits a loud groove - audio can also be 'thin' and trebly. Too much and you can physically scrape & damage your record. Most turntables and cartridges recommend around 2 grams, but cheap and poorly made turntables can be up to 10 grams, which will destroy your records after several plays.
Anti-Skate - the tonearm is setup to pull or drift in toward the center of the record, helping the needle reach the 'end' of the disc. Anti-skate is a small force to counteract this. If it's not set correctly the needle will press against one of the sides of the groove harder - giving you an unbalanced sound, and wearing down that side of the stylus and record groove.
Wow/Flutter - the effect that gives records an old-timey 'wahrbly' sound. Causes can vary from motor speed changes, mechanical issues (belt), uneven / wavy record surface, off-center record hole. In short, anything that stops the record from spinning at a constant speed, and the needle from riding along at a steady angle & weight.