SP A700 vs G250V

[rstofer]

OK, the subject is cold water regs (groan!). I'm pretty convinced I'll buy the Mk17 first stage. No question there.

But, in looking at the SP lineup, I see that the A700 second stage is all metal whereas the G250V has a plastic housing (with metal components). OTOH, I see from the user manual that the G250V has an anti-engraving feature that allows me to depress and turn the diaphragm to remove pressure from the LP seat.

It seems to me that the all-metal housing would be ideal for cold water but I don't really know that. I also note that the front cover of the A700 isn't removable without tools so I suspect it won't be a hit with the cave diving bunch. I'm not ever going to be a cave diver.

Now what? I had kind of settled in my mind that at some point in time I would buy the Mk17/G250V. It was my 'gold standard' but now I'm beginning to wonder...

Any thoughts? FWIW, cold (in my definition) is >= 40 deg F. I'm not going to be an ice diver either.

Richard

 

[Bubbletrubble]

OTOH, I see from the user manual that the G250V has an anti-engraving feature that allows me to depress and turn the diaphragm to remove pressure from the LP seat.

Since you bring this up, what's to stop you from rigging up something like that on your own with a different reg? I'm thinking along the lines of bungee cord and a disc that fits on top of the purge button.

I can see how keeping the purge button pressed down will depress the lever which takes pressure off of the LP seat. Over time will this place too much stress on the purge spring and poppet spring? On account of this, will these parts have to replaced at more frequent intervals? Just curious. No hijack intended.

 

[a22shady]

I dive in the northeast So i am also in cold water. I have the MK17/G250V and love it it's a great reg. So far coldest water I have been in is low 40's with no problems. I also have an Atomic M1 set which is also great. Although I have the M1 on my MK17. the M1 qst stage is sorta sealed piston and I see people diving those all the time and have no problems in Cold water but with those becaus they are sealed by filling the Chamber with Trbolube they are not a true sealed 1st stage which is why I use my MK17. and Personally I have had them both hooked up each way and noticed no difference in breathing performance.

Not to mention Halcyon has taken a liking to the G250V Also.

 

[halocline]

I would be surprised if there any appreciable difference between the cold water performance of the G250V and A700. Then again, I would also be surprised if there was any appreciable difference between these two and the original G250, or balanced adjustable. The balanced/adjustable is quite a bit heavier; actually it might be the most freeze resistant of all of them. That's a guess.

 

[DA Aquamaster]

The original G250 was very reliable in cold water due to the metal air barrel that is exposed with a metal adjustment knob on one end and a metal inlet fitting nut on the other end. The G250V expands on this with an inlet fitting nut that is a bit wider and deeper with more surface area for even better heat transfer.

There is no arguing that the all metal Adjustable and Balanced Adjustables were superb in terms of heat tranfer and I suspect the A700 would be just as good. But it is a noot issue as the G250/G250V is already more than up to the task.

I would tend to avoid the A700 for tehcical diving for the reasons stated above - and franknly, that really pretty and very shiny chrome is not going to be pretty for long in a techncial diving environment.

 

[Belce]

I have been diving the A700/Mk25 here in the north west since it was first available in June here. Scubapro doesn't make a better reg combo for diving in salt water that doesn't have frozen water overhead.