Turntables Part 2

If anyone is interested I will give a few pointers on buying a used turntable.

There are generally 3 types of drive systems to a turntable. Belt drive, rim drive and direct drive. They all have an electric motor located inside the turntable, under the platter. When it is plugged in, and turned on the motor spins. Different things happen when you switch between 45, 33 1/3 ( or sometimes 78), on the three types of drives.

On a belt drive, the belt is moved to either a larger or smaller diameter step on the motor pulley, depending on what speed is selected. On some models, the platter has to be removed to manually switch between 45 & 33 1/3. On a rim drive, the motor spins a rubber wheel. This wheel runs against the inside/underside of the platter. When switching speeds the rubber wheel moves up or down to either a thicker or thinner section that spins the platter. On direct drive the motor is connected directly to the platter. The speed change is either handled by gears or magnets.

Each style has its advantages and disadvantages:

Belt Drive Disadvantages: Belts are made of rubber, wear out and stretch. Whenever buying a used belt drive always factor that it should have a new belt, and if you can’t change it yourself there will be labour costs, so factor that into the purchase price. even a belt that is not brand new can have some stretch and affect speed. Sometimes platter has to be removed to change speeds.

Belt Drive Advantage: The potential for sound quality is the best with a belt drive turntable. The rubber belt helps to isolate the vibrations, motor rumble and noise that emanate through the speakers.

Rim Drive Disadvantages: Usually only found on older models. Higher noise caused by the motors. The motors spin at very fast speeds, so can burn out quicker. Rubber wheels wear out.

Rim Drive Advantage: Most common issue is rubber wheel slipping. Often lightly rubbing with very fine emery cloth etc. will scuff it enough to make it not slip, so this drive may be cheaper and easier to service.

Direct Drive Disadvantage: This design leads to the most issues with rumble and noise emanating through the speakers, especially when the bearings get worn. If something needs replacing, it is usually a more expensive part that fails.

Direct Drive Advantage: Less Maintenance, is the best at speed regulation, and getting up to speed quickly. For these reasons this is the style dj’s prefer.

Cartridge(the end of the tone arm into closest to the record) and stylus(needle): When buying a used table, check to see if it has a cartridge, ask how old it is, and research the make and model. This could easily make a decent $100 turntable turn into a $200-300 or more turntable. Also check the style of cartridge. Some are a p-mount design which limits the available cartridges that fit the tone arm.

Check the weight of the turntable. Usually a heavier model is built solidly, and will have less chance of emitting noise through the speakers.

One thing to consider is what amp or receiver you will be using. Since the 1990’s, most receivers do not have a dedicated phono plug. If you look on the back of your receiver and it does not say phono above a plug, you can not plug your newly bought turntable into it. So you will now need a pre amp, an electric device that changes the frequency so it can be played through your receiver. They can be bought as cheaply as $20, but you often get what you paid for. The above is also something to consider when shopping for a receiver as well.

Do some research on any model you want to buy. Check forums such as stevehoffman,  audiokarma, head-fi etc. Google your make and model. I have made the mistake of bringing home a cheap turntable only to find it needs a p mount cartridge(which have way fewer and more expensive options), needs a belt, and a complete service. If I had invested the money in the repair, I would have a lower end model worth half my investment. It sometimes is worth spending a little more to find an “audiophile” quality turntable that has been looked after and perhaps recently serviced.

I am in the process of restoring a Dual rim drive turntable. I will submit a new entry when I am done, and perhaps another one comparing the sound quality of the same record played on 3 turntables with different drives.

For now, I will leave with an article from 1958 that is still relevant in 2015.

Good luck on the turntable search.

http://www.djsociety.org/Turn%20History.htm

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