The difference between a DIN regulator first stage and a yoke regulator first stage is the manner in which the regulator attaches to the tank. A DIN regulator screws into a tank valve, and a yoke regulator fits over the top of tank a valve and clamps onto it with a tightening screw. The DIN system is by far superior, but a diver may find it preferable to use a yoke regulator depending upon his style of diving and tanks.
Quick Check: Am I Using a DIN or a Yoke Regulator?:
What Is a Yoke Regulator?:
A yoke regulator, also known as an A-Clamp regulator, has an oblong metal brace that completely encircles the tank valve when in place. The regulator first stage is located at one end of the brace, and a large screw, called the yoke screw, is located at the opposite end. To attach a yoke-style first stage to a tank, a diver fits the metal brace over the tank valve, and then tightens the yoke screw to clamp the first stage firmly in place.
What Is a DIN Regulator?:
A DIN (which stands for Deutsche Industrie Norm) regulator first stage has a threaded post that screws into the inside of the tank valve. A DIN regulator's first stage fits into one side of the tank valve, and no additional metal or braces run behind the tank valve.
Yoke and DIN Regulators Require Different Tank Valves:
Yoke regulators use a more-or-less flat tank valve that has an o-ring pressed into a small grove on the flat side of the valve.
DIN regulators use a tank valve with a large, threaded opening that allows the threaded post of a DIN regulator to be screwed inside the tank valve.
Yoke and DIN Regulators Differ in the Location of the O-Ring:
A regulator first stage seals to a scuba tank valve by means of an o-ring. DIN and yoke regulators have the o-ring in different locations. Tank valves designed for use with yoke regulators have the o-ring in the tank valve. DIN regulators have the o-ring incorporated into the regulator instead of the tank valve.
The location of the o-ring in the DIN system is superior. O-rings have been known to extrude from around a yoke regulator attachment while it is in place and pressurized. This causes a major leak. In contrast, the o-ring for the DIN system is located at the end of the post that threads into the tank valve. The o-ring is “captured” behind the post, and there is no way for it to extrude. In diver jargon, an o-ring that can not extrude is called a captured o-ring.
Yoke and DIN Valves Are Found on Different Kinds of Tanks:
Yoke valves are common throughout North America and recreational tourist destinations. They are standard on most Aluminum 80 cubic foot tanks (Al 80).
DIN valves can handle higher pressures than yoke valves, and are used on high pressure tanks. They are also found on Al 80's in Europe and some other parts of the world.
Different Kinds of DIN Regulators:
To make matters more confusing, there are two different kinds of DIN regulators and DIN valves: 200 bar and 300 bar (bar is the metric unit of pressure). 300 bar valves are deeper and require a regulator with a longer post with more threads. The difference lies in the amount of pressure the tank valve is rated to withstand. There is not much difference as far as the regulator is concerned because the first few threads of the post do all the work. A 300 bar DIN regulator can be easily used on a 200 bar tank valve, but a 200 bar regulator will not seal properly to a 300 bar tank valve. It doesn't make much sense to buy a 200 bar DIN regulator.
Which is Better, Yoke or DIN?:
DIN is the superior system by far. The o-ring is captured behind the regulator post, eliminating the chance that it may extrude and create a dangerous situation. Because the o-ring is in the regulator, a diver with his own regulator brings his own o-ring to the dive, and can be certain not to be stuck with worn out, damaged o-rings sometimes found on rental yoke-valve tanks. DIN regulators can be designed to withstand higher pressures than yoke regulators. It is possible to knock a yoke regulator off the tank if the tank is dropped or struck (not an ideal situation). This is nearly impossible to do with a DIN regulator. DIN regulators are also more streamlined than yoke regulators, and generally weigh less.
Which Regulator Style Should I Buy, Yoke or DIN?:
A diver needs to consider where he will be diving, what tanks he is likely to be using, and what sort of diving he intends to do. Al 80's with yoke valves are the standard in North America and in most recreational warm-water diving locations. Many divers only plan to do this sort of diving. They should go with a yoke regulator.
If a diver plans to engage in technical diving or use high pressure tanks, DIN is the preferable configuration.
Your Choice Is Not Final
DIN regulators can be converted to the yoke system and yoke regulators can be converted to the DIN system with the appropriate service kit. This is a quick conversion, and is easy for a knowledgeable service technician.
In addition, adaptors are available to use DIN regulators on yoke tanks and vis-versa. The only problem is that the yoke adaptor for a DIN regulator is a little bulky and may cause the regulator first stage to stick out and bump a diver's head. Divers who are planing on diving primarily with yoke tanks may want to get a yoke-style regulator for this reason.
The Best of Both Worlds
For divers who want the option to do everything, the best choice would be to buy a 300 Bar DIN regulator and a DIN to Yoke adaptor. This will cover any valve situation.