NorthernShrinkage:
The part I dont understand is how come more regulator manufactures dont give you the choice between the 2 instead of making Yoke standard and having to purchase A conversion kit ? Most of the higher end stuff you have the choice but mid range is usualy Yoke.
Regs made by most companies are offerred in both DIN and yoke models, they are just not always stocked or cataloged that way. And you can't blame the company or the LDS as yoke connections are much more common and are still more or less the standard in North American recreational diving as well as in most of the dive destinations in this hemisphere. If you dive the carribean, a DIN reg will usually result in you having to tolerate a DIN to yoke adapter.
DIN equipped regs cost slightly more than their yoke counterparts in most cases, but the price is still cheaper than buying yoke and converting or adapting so if you really want DIN as the LDS to special order you one that is DIN equipped to start with.
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I use DIN for my technical diving and I greatly prefer it due to the elimination of the yoke knob, which seems to magnetically attract nets, lines, etc. That said however, the "DIN is stonger" argument really does not have much merit unless:
1. You are scootering through caves and plan on impacting the ceiling now and then or,
2. You use high pressure tanks (over 3442 psi).
The real advantage of DIN my opinion is much better streamlining.
Contrary to popular opinion, the o-ring on a yoke connection is indeed fully captured just like it is in a DIN reg, the only difference is in how it is captured. With a yoke connection, if it is properly manufactured and in good condition, you will have metal to metal contact between the first stage orifice and the valve face as long as the yoke knob is snug and the connection will leak if the knob is not secure. However the same thing is also true with a DIN fitting.
The difference is in the location of the o-ring. When a yoke connection is loose, the o-ring (since it is contained in the valve) will usually extrude out of it's seat in the valve and "blow out". When a DIN fitting is loose, the connection will still leak, but the o-ring (since it is contained in the regulator itself and is not blocking the path of the leaking air) will not be blown out of its seat.
Above water this makes no real difference in safety as if the o-ring is blown out, you remove the reg, reseat the o-ring and reconnect the regulator, or worst case replace the o-ring from a save a dive kit and reconnect the regulator. With a DIN connection you save about a minute as all you have to do is tighten the connection.
Underwater is a different story as if, for example, the yoke connection on your depressurized deco bottle comes loose, and the o-ring unseats when you repressurize the reg, it is a major PITA to reseat or replace an o-ring underwater and first stage flooding is guarenteed to be significant. In contrast if your DIN connection on your deco bottle comes loose, you tighten it and flooding, if any, is usually very minor and the reg is usuable in seconds. On the other hand in my experience DIN connections seem to be more prone to loosening themselves on unpressurized regs than yoke connections as I have had it occur on DIN regs but have never had it happen on a yoke reg. The wheel on a DIN reg is ammenable to being moved if brushed by an arm etc, while a yoke connection is quite tight at the start of the dive and gets tighter in cold water as the yoke contracts slightly at the lower temps. Often after a cold water dive they can be hard to intentionally loosen and remove by hand.
In my opinon, the poor reputation of yoke connections and the whole "uncaptured o-ring" myth is the result of two things:
1. Older lightly constructed 2250 psi yokes used on 3000 psi tanks where they stretched slightly when pressurized resulting in the loss of metal to metal contact.
2. The increased potential for the mating surface on the valve face of a yoke valve to become damaged over the life of the valve compromising the metal to metal contact.
So the problems with yoke valves and o-ring extrusion are due to innappropriate usage and poor maintenence rather than an "uncaptured" o-ring design. With modern yokes, improper usage is not an issue as currnent yokes are constructed so that they will tolerate 4000 psi before they begin to stretch and most are rated to 3442 psi whether the manufactuerer sanctions their use to that pressure or not. In the case of poor maintenence, stupidity it is still going to be a problem even with a DIN valve, the differnece is that if you drop a DIN valved tank on its valve the odds are good that the female connection will be bent rendering the valve unusable and therby protecting the moronic diver from actually diving with a potentially damaged valve. With a yoke valve in the same situation it would be possible for a moronic diver to fail to inspect the valve face and detect significant damange, start the dive and experience a catastropic gas leak in the middle of the dive. So DIN is clearly a better option for divers who are total idiots.
The only real downside to a DIN valve in my opinon (other than limited travel availability) is that they hold water much more readily that a yoke valve and offer greater potential for water dropplets to be introduced into the tank during a fill so somewhat greater care is required in the filling process.
