Your favourite second stage and *why?
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Apeks ATX200 for primary and Mares Navy 22 Abyss for pony.... Reliability, dependability, adjustability and solid history of no issues for me.
The G260 has the micro adjusting feature. This makes it easier to set up than a G250. The G250, the spring (force) is what it is, with a G260 I can tune the spring, that is the "10%" difference right there. A G250 it is grab another spring and another (if you have dozens to choose from) until you find the best one. IMO, a G250 with the perfect spring and the latest parts should inhale on par with G260.
The G260 reads higher on my Magnehelic by a skosh on exhaust effort than does any of my G250s. I think the vertical vane behind the exhaust valve needs a tiny bit more clearance but I am reluctant to modify a brand new G260 set to relieve the contact area without first understanding why Scubapro did what they did there. The difference is minimal.
My new to me and "very, very expensive and worth every penny" CE BA156 I have not enough experience yet with it to really get into the minutia. I am going to say that the G250 and the G260 have more Venturi if the vane is fully in the DIVE position than the 109/156. I am also going to say that on my Magnehelic I see a still slightly higher exhaust effort despite the now full size (30mm+) exhaust valve and I think that possibly is the tee. I have not tried any without the tee. Compared to the 109, the exhaust effort of the CE 156 is noticeably lower. BTW, the Conshelf wins again, it has the lowest average exhaust effort vs any of the SP regulators, this the result of a large exhaust valve, a huge bell manifold and a honking
huge exhaust tee.
AL would do themselves well if they would reintroduce the Conshelf even if it were polymer (and glass filled like the SP G series). But this time add in an adjustment knob to back spring force down to zero (Kirby Morgan). No, not a balanced adjustable, just an adjustable poppet spring. Foo, foo on a balanced XXXX! Pneumatic balancing of second stages just a complication. A well designed case and Venturi is all that is needed to achieve very low WOB. And a Venturi adjustment is not needed on the Conshelf because it had peripheral vents and was not prone to free flow into current despite a fairly aggressive Venturi. Just a spring force adjustment knob please Aqualung! Oh, and an adjustable volcano orifice too please.
The G260 reads higher on my Magnehelic by a skosh on exhaust effort than does any of my G250s. I think the vertical vane behind the exhaust valve needs a tiny bit more clearance but I am reluctant to modify a brand new G260 set to relieve the contact area without first understanding why Scubapro did what they did there. The difference is minimal.
My new to me and "very, very expensive and worth every penny" CE BA156 I have not enough experience yet with it to really get into the minutia. I am going to say that the G250 and the G260 have more Venturi if the vane is fully in the DIVE position than the 109/156. I am also going to say that on my Magnehelic I see a still slightly higher exhaust effort despite the now full size (30mm+) exhaust valve and I think that possibly is the tee. I have not tried any without the tee. Compared to the 109, the exhaust effort of the CE 156 is noticeably lower. BTW, the Conshelf wins again, it has the lowest average exhaust effort vs any of the SP regulators, this the result of a large exhaust valve, a huge bell manifold and a honking
huge exhaust tee.AL would do themselves well if they would reintroduce the Conshelf even if it were polymer (and glass filled like the SP G series). But this time add in an adjustment knob to back spring force down to zero (Kirby Morgan). No, not a balanced adjustable, just an adjustable poppet spring. Foo, foo on a balanced XXXX! Pneumatic balancing of second stages just a complication. A well designed case and Venturi is all that is needed to achieve very low WOB. And a Venturi adjustment is not needed on the Conshelf because it had peripheral vents and was not prone to free flow into current despite a fairly aggressive Venturi. Just a spring force adjustment knob please Aqualung! Oh, and an adjustable volcano orifice too please
.
The G260 is basically the G250Hp reborn with some further refinements...
Both use a micro-adjuster to tune it.
Both use a micro-adjuster to tune it.
Beau Holden
Contributor
Dive Rite RG1210 2nd paired with RG1208 1st
Has served me well for over14 years. Still dive my 1st set and have 6 sets of them currently.
Service parts easy to get.
Owner of the company dives (dived) them.
Has served me well for over14 years. Still dive my 1st set and have 6 sets of them currently.
Service parts easy to get.
Owner of the company dives (dived) them.
Nope, on EAN50
Geo7
Contributor
In the @rsingler videos about the D420 he discusses the exhaust diaphragm pressure and observes that in the sort of face down diving position, the exhale pressure is somehwat aleviated by the membrane facing up, and crucially, a reg with the usual case geometry fault can be set to lower inhalation resistance and not leak throug a stiffer exhaust membrane at its worst angle. The stiffer exhaust valve keeps it from bubbling if set slightly below 0.9" or so, if I understood correctly? Perhaps that is what Scubapro is doing nowadays, optimising the regs for performance in "diving position".
Geo7
Contributor
I wonder how the Conshelf compares to the mares Abyss? Is that question even allowed?The G260 has the micro adjusting feature. This makes it easier to set up than a G250. The G250, the spring (force) is what it is, with a G260 I can tune the spring, that is the "10%" difference right there. A G250 it is grab another spring and another (if you have dozens to choose from) until you find the best one. IMO, a G250 with the perfect spring and the latest parts should inhale on par with G260.
The G260 reads higher on my Magnehelic by a skosh on exhaust effort than does any of my G250s. I think the vertical vane behind the exhaust valve needs a tiny bit more clearance but I am reluctant to modify a brand new G260 set to relieve the contact area without first understanding why Scubapro did what they did there. The difference is minimal.
My new to me and "very, very expensive and worth every penny" CE BA156 I have not enough experience yet with it to really get into the minutia. I am going to say that the G250 and the G260 have more Venturi if the vane is fully in the DIVE position than the 109/156. I am also going to say that on my Magnehelic I see a still slightly higher exhaust effort despite the now full size (30mm+) exhaust valve and I think that possibly is the tee. I have not tried any without the tee. Compared to the 109, the exhaust effort of the CE 156 is noticeably lower. BTW, the Conshelf wins again, it has the lowest average exhaust effort vs any of the SP regulators, this the result of a large exhaust valve, a huge bell manifold and a honking
AL would do themselves well if they would reintroduce the Conshelf even if it were polymer (and glass filled like the SP G series). But this time add in an adjustment knob to back spring force down to zero (Kirby Morgan). No, not a balanced adjustable, just an adjustable poppet spring. Foo, foo on a balanced XXXX! Pneumatic balancing of second stages just a complication. A well designed case and Venturi is all that is needed to achieve very low WOB. And a Venturi adjustment is not needed on the Conshelf because it had peripheral vents and was not prone to free flow into current despite a fairly aggressive Venturi. Just a spring force adjustment knob please Aqualung! Oh, and an adjustable volcano orifice too please
They are comparable. Very similar and I have not seen a recent Abyss but the Conshelf has a better designed exhaust side IMO and I could be wrong. I just have not seen a newer Abyss part enough to know. The inhale side, very, very similar, one has an external Venturi assist and the other an internal fixed vane or guide if you will. Both work very well.I wonder how the Conshelf compares to the mares Abyss? Is that question even allowed?
I was just thinking about that. They are very close in design except for the VAD bypass tube on the Abyss. VAD performs the same function as the venturi widgets on most seconds, i.e. keeping a lower pressure area next to the diaphragm when has is flowing. This reduces the inhalation effort to keep the valve open once you start a breath. And since it's a large tube with no vanes or obstructions in the air path, it can flow a lot of gas.I wonder how the Conshelf compares to the mares Abyss? Is that question even allowed?
It works really well in Mares regs, it may take a tiny bit more effort than a balanced to initiate a breath, but once it's cracked you get as much gas as you want with almost no effort no matter the work level.
I can't comment on the exhaust side. I've never really thought about it until Nemrod's comments.
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