DD Turntables by MC

The Tonearm

 - Cick on pictures to supersize.

 

The Tonearm is of course of vital importance on any Turntable, be it a Direct Drive, Belt Drive or Idler-Wheel model. There are probably almost as many different arm designs as there are TT models and to name the best is an all but impossible task. It will depend on your TT, your cartridge and other factors such as convenience for example.

It is though, important to understand the fundamentals of the tonearm. First, its main function is of course to hold the cartridge, but that is no small feat considering the minute tolerances involved! The arm really has to as stable as possible in order for it to be immune to unwanted resonances and vibrations, but at the same time it has to be light and have as low friction as possible. So here there is really a conflict. Furthermore, the length of the tonearm is critical. It can't be too short or the tracking error will be too big. Long arms have the smallest tracking error but they are heavy and prone to resonses and will only work well with heavy and low compliance cartridges. This is true to conventional Radial arms. Tangential arms will have close to zero tracking error and can be very short and light. They also have very low friction. So all in all - manufacturers really do have to work hard to develop high quality arms.

Tonearms can roughly be divided into two main categories.

The first and by far the most common is the RADIAL tonearm that is mounted at one position and then swings out over the record as the cartridge tracks the grooves on the vinyl record. This kind of tonarm can be of differnt lenghts and made out of a variety of materials ranging from wood to carbon fiber. The most common material is some sort of lightweight aluminium. The arms can even be of an active electronic design with built in coils and magnets to move the arm and also actively dampen the ever unwanted resonances.  

The other main type of tonearm is the TANGENTIAL arm. This arm works in a totally different way. It tracks the grooves by moving tangential to the record i.e. parallel to the tangent of the record. This type is in theory the most ideal type for a TT for several reasons. FIrst, it tracks the records in the same way as the actual cutting machine that engraves the master record in the first place. Second, the tracking error, or the deviation from the ideal tracking angle of the cartirdge is kept very close to zero with deviations measured in 1/10 of a degree while most Radiial arms have errors of 1-3 degrees. Third, the length and thereby the mass of the arm can be kept at a minimum so high compliance cartridges with very low needle pressure and thus record wear can be used. However, as very often is the case, theory and practice are two very different cases . . . There can be no real evidence as to which type is the best, it will depend on what your critererias are.

This is once again my DP75M and it uses a long 12" arm. The armtube is interchangeable with both the S-type on the picture and straight lower mass ones seen on the plinth. Different sub-weghts for the different arms and different cartridges. The S-Type arm can even carry a classic SPU - not an easy task! 

This is a J-shaped arm on a Sony PS-X65. It is an electronic variant of the very succeful and well made PUA-7 from Sony. This arm is an electronically controlled arm which actively dampens out resonances in the horizontal plane. The big brother, the PS-X75's arm also has vertical resonance damping much like the JVC and Denons below.

This is a Pioneer PL-L1000 - Pioneer's statement player (outside Japan) in the early 80s. It uses a real high-tech Tangential arm with a LINEAR motor. The arm is actually part of the motorsystem and there is no wire to pull it along. A real technological achievement by Pioneer at the time.

This is really a fine example of just how far the japanese companies would go into R&D when developing advanced automatic TT's. It's a fully electronic arm on a JVC QL-Y66F. Inside the arm there are coils and magnets which move the arm both horizontally and vertically with absolutely no mechanical contact and super smothly. It also actively dampens out resonanses! It also has intercheable arm wands, both straight and S-formed to fit many different kinds of cartridges. A supremely designed automatic arm. This model can be seen as the pinnacle of Japanese Automatic DD turntable design just as CD's were taking over in the mid 80s.

This is an electronic arm much as the former JVC but made by Denon. The colils controling arm movement and supressing resonances ca be seen. This arm is simpler than the JVC one but works in similar fashion. It is found on the low to mid-range automatic players. One of the better and probaly most common was the DP-47. Many of the higher-end Denon models also used electronic arms, such as the DP-59, 62, 67, 72 and even the monster DP100, not for automatic arm movements but solely for resonance control. 

This is a Pioneer PL-L800 - the little brother to the PL-L1000 with a Tangential arm. The arm is made of polymer graphite and is very light and stiff. It's also a direct drive arm with no wire to pull it along. This makes it very smooth and quick to react. It can be moved by hand or with buttons.