Everything You Need To Know About Turntables, And Phonographs - Part 1

In the past century there have been a variety of vinyl record types this is not uncommon as cassette tapes, Compact Disks and Digital Video Disks have all gone through a series of generations.

Types Of Vinyl Records

Vinyl records have come in a variety of speeds and sizes. 12" records are either 33 1/3 or 45 rpm and 10” records are mainly 78 rpm but there are some that play at 33 1/3 rpm, and 7” records are 45 rpm and there are larger 78's but these are pretty uncommon.

Records can also be defined by quality, vinyl disks have different weights to them ranging from temporary paper thin pressings to 180 gram disks that feel solid and don't flex much at all. Some classical recordings are still sought after because of their quality of pressing. Today's composites and pressing methods are superior to older records from the 60s and 70's but seem to be pressed on light weight flexible disks that are prone to warping or having manufacture defects within the stamping process.

Turntables

There has always been some sort of mystery around turntables or phonographs and the ability to recreate analogue sound using up to hundred year old recordings. Since record players have been used to playback sound for this long, I am only going to cover the technologies of turntables or record players created after world war 2 when portable phonographs became widely available. Record players suffered a die back during the 8 track and tape revolutions of the 60s through the 80's but have persisted to be the preferred playback device of audio enthusiasts for the last century with no sign of being "outdated" anytime soon.

How A Turntable Works

A groove on a record is stamped with grooves and bumps within the groove this is the record data, the record is then placed on the turntable, and a motor starts rotating the record at a consistent speed of 33 1/3 , 45, or 78 revolutions per minute. A stylus/needle rides along the groove of the record and creates a vibration. This vibration is picked up by magnetic coils within the cartridge, and turned into electrical signal. The electrical signal is then outputted from the turntable using RCA cables to a phonograph preamplifier. the preamplifier boosts this signal to a level that is similar to that of a CD player, or tape deck out put. The signal is then finally amplified by your stereo receiver and sent to your speakers where magnetic coils vibrate to generate the sound wave that you ears hear.

Counter Weights

You can usually tell the quality of a cheap turntable when they have a plastic counter weight, a machined alloy counterweight with weight unit measures marked on it is a sign of a higher quality record player.

Counter weights should be adjusted according to the needle specifications usually between 1.5 and 3.5 grams of pressure. This can be tuned by using a jewelers scale which will give an accurate weight measurement for the needle pressure.

continue reading part 2 of this article