Looking for a great 1st regulator!! HELP :)

[USdiver1]

For ease of maintenance as you travel far and wide (you say that you are planning a world scuba tour with your regulator) I'd go with with either Aqualung/Apeks or Mares brands, due to their universal availability and ability to be rebuilt by LDSs the world over. Aqualung Legend Supreme, Apeks XTX 100, and Mares Abyss 42 should all be seriously considered. Test dive a few if you can, prior to purchase then get your favorite.

 

[herman]

I only go for the over-over balanced.

Lots of hype out there, "over balanced" is a beauty. Gee, we're just not selling enough of our "balanced" regulators, lets call them "over balanced".

I actually went to the trouble to figure out what the "over balancing" was. The math works out to around an extra 15 psi of the IP at 100ft. I seriously doubt a diver would notice the difference.

 

[Kunundrum]

My Choices

Any (Sealed) Atomic Regulator
MK17 / G250V
XTX50
Legend LX Supreme

 

[halocline]

I actually went to the trouble to figure out what the "over balancing" was. The math works out to around an extra 15 psi of the IP at 100ft. I seriously doubt a diver would notice the difference.

Especially when the extra IP is more or less equalized by the balanced 2nd stage.

 

[obada.jandali]

now i had a thought, lets say for example that i had a regulator crisis, and the mech inside the 1st stage broke down, would a diaphragm free flow as the piston would do?? anyone got any idea about that?

 

[RJP]

now i had a thought, lets say for example that i had a regulator crisis, and the mech inside the 1st stage broke down, would a diaphragm free flow as the piston would do?? anyone got any idea about that?

Most regulators (all except Poseidon?) are a fail "safe" design, meaning that if they fail, they will fail with the demand valve OPEN and freeflow, as oposed to failing "closed" and not delivering air. This is true for both piston and diaphragm designs.

 

[carrielsal]

I own both Legend LX's and Apex XTX200's. Both are great regs.

 

[herman]

Most regulators (all except Poseidon?) are a fail "safe" design, meaning that if they fail, they will fail with the demand valve OPEN and freeflow, as oposed to failing "closed" and not delivering air. This is true for both piston and diaphragm designs.

That is only true of down stream second stages when combined with excessive IP, it keeps LP hoses from blowing up, otherwise, any design of both first and second stages can all fail in either condition, it just depends on what the defect is. For example, a broken spring on a diaphram first will cause its IP to drop radically and depending on the amount of spring failure it can go to zero or a broken lever in a second stage will cause total OOA of that stage. Both failures are very rare but can happen. By far the most common failures do cause a freeflow but a blanket statment that they will always fail open is not accurate.

 

[keyshunter]

I actually went to the trouble to figure out what the "over balancing" was. The math works out to around an extra 15 psi of the IP at 100ft. I seriously doubt a diver would notice the difference.

Herman,
I agree that IP increase in "overbalancing" is rather insignificant, especially with a balanced second stage and at recreational depths. I am, however, curious about how you calculated the "extra 15 psi" IP rise.

 

[herman]

Not difficult, I don't have the exact math/values in front of me but basically IP is a function of spring pressure and force applied to the diaphram. On "normally balanced" regulators the surface area of the diaphram is selected to give a 1 to 1 ratio of pressure increase to depth or in other words as you increase ambient pressure by 1 psi (about 2 ft of depth) the IP also increases by 1 psi. On an OB reg, the diaphgram has a slightly bigger diameter so instead of a 1:1 ratio it's a little more. I forget the exact numbers but its something like 1.25:1 so instead of a 50 psia increase in IP at 100 ft you get a 65psia increase. Reguardless, it does little unless you are using the reg at full flow...something a diver will never do and it introduces second stage tuning problems. On balanced seconds it's not a problem, they will deal with the extra few PSI- that is the whole purpose of balancing a second stage but if you use unbalanced second stages they will have to be set up for excessive cracking pressure at the surface, otherwise they will freeflow at depth. Most octos are set pretty tight anyway but if it's set close to the edge it will freeflow with the extra few PSI.