Help to identify and advise on an older Poseidon regulator

[Fitzgig]

I have scanned the board but have not found the definitive answer. I am a noob- so it could be inexperience. Apologies in advance.

My sister gifted me her old Poseidon regulator and the only thing I know is that they are nearly impossible to get serviced in the US - but that they are well manufactured. Can someone help me identify and advise me on whether it is worth the difficulty /expense to have it repaired? @rsingler seems to be THE guy to ask, but any advice is valued. Sounds stupid, but I would like to use them in the future in my sister’s memory. I think the manufacture date is 1996, back when she was a healthy vibrant dive master……

 

[billgraham]

You want a lighter weight swivel that meets your needs without the extra weight of the Omni-Swivel twisting the Jetstream in your mouth a bit?
Try @Fibonacci 's new adapter on an Atomic Comfort Swivel. Then adapt it to the exact length you want with an Omni-Swivel male end hose adapter. Simply awesome!

And yes, I'm just a little disappointed in the XStream second. While I don't find freeflow a problem as an auxiliary without the switch, and the form factor is nicely smaller, it sure is loud in my left ear, and seems to have just a hair more exhalation resistance during heavy breathing at depth.

@Fibonacci, do you have a link for this widget? @rsingler, I kind of like the showerhead design of the Jetstream because you can just shove it through a bungee loop to stow it on a bottle or harness and pull it right out.

 

[rsingler]

@Fibonacci, do you have a link for this widget?

Thread For Sale - Poseidon Jetstream XStream SCUBA regulator to Atomic Comfort Swivel Adaptor 0000-130-ACS

Was that observation of yours the result of those multiple regulator tests that you made in the Keys last year or the year before?

Yeah, that's where it came from. I think the smaller exhalation valve is part of the resistance issue, and the noise is minor. It's the old "blind wine tasting" problem. Your most expensive favorite wine goes into a paper bag next to your buddy's favorite. Suddenly, subtle differences jump out when you taste each one, not quite knowing what's in the bag.
No reason to dislike the XStream. It's a great reg.

 

[Fibonacci]

Do you suppose that that is simply do to the tiny size of second stage diaphragm, compared to that of the Jetstream, at about twice the diameter -- which also happened to be the same as that of both Cyklon second stage diaphragms -- both of which are easy breathers?

I hadn't really noticed that exhalation issue, since I most typically use the XStream second stage guts in the Atmosphere mask, which uses that larger Jetstream housing. It still remains the best FFM that I have used, in terms of ease of breathing.

Was that observation of yours the result of those multiple regulator tests that you made in the Keys last year or the year before?

I measured the area of the two exhalation ports in 3D CAD... clearly I need to get out more, this is not a good start for Day 2 in 2024

The Jetstream has 15 smaller exhalation ports totalling 410.4 square mm vs the XStreams 8 more conventional looking larger ones totalling 484.6 square mm, so theoretically the XStream should have 15.3% less exhalation resistance esp at depth where the gas is much more dense. Maybe that's why the XStream passed the 200m NORSOK U-101: 2013 Diving Respiration Equipment Standards when the Jetstream apparently didn't?

Are the bubbles smaller in the Jetstream due to the reduced size and increased number of vent holes?

I think it may also come down to the difference between the Jetstream's coaxially positioned intake/exhaust diaphragms vs the separate planar intake and exhaust diaphragms on the XStream combined with surface area of the diaphragm exposed to ambient water pressure vs the contact footprint of each exhaust valve? Complex...

 

[Bigbella]

I measured the area of the two exhalation ports in 3D CAD... clearly I need to get out more, this is not a good start for Day 2 in 2024

So, what else do you do in your spare time, while recovering from New Year's Day?

I am still looking for a pair of socks on day-one . . .

 

[billgraham]

Thread For Sale - Poseidon Jetstream XStream SCUBA regulator to Atomic Comfort Swivel Adaptor 0000-130-ACS

I'll have to take a close look at the Atomic swivel hose to see if that will work for me. I'm routing the regs around my head, the short hose one is on a necklace, so it's most comfortable at about a 90 degree angle. The argument against the swivels was always that they were an additional failure point. Where I'm diving, the water has a high limestone content so that fine dust gets into everything and things like the tiny O-rings on pressure gauge spindles fall apart really fast. I've been diving the Omniswivels for about a year, and they've worked well and now I can't believe I didn't use them sooner, comfort wise. If I look at "selfies" I took with the big camera years ago on OC, I can see how the stiff Poseidon hose was pulling on the reg in my mouth.

 

[Fibonacci]

While they don't seem to have much love on SB I still regard the Atomic Comfort Swivel (ACS) as an exceptional 'elegantly simple' streamlined design that is very reliable and easy to service vs the Omniswivel with exposed fastener that has the potential to unscrew.
The going rate for a used ACS hose is around US$50 and unless very abused (corroded under the protective cupped rubber hose extension area) rarely give any trouble.

I've used the ACS in tropical locations where there was very fine coral dust suspended in the water nearer the shore and never had a problem. With my Poseidon adaptor, there are only two o-rings to replace, a captive one at the attachment point to the reg and a dynamic one at the swivel. The OEM service kits also include a replacement low friction cup, but I've found these rarely need to be changed.

 

[Bigbella]

I too have used the Atomic hose and Fibonacci's fitting on my FFM, regularly, heavily since last Spring, in areas of the finest suspended silt, without issue; but I do soak my pressurized regulators for some hours after every use . . .

 

[Michelle Louise]

I measured the area of the two exhalation ports in 3D CAD... clearly I need to get out more, this is not a good start for Day 2 in 2024

The Jetstream has 15 smaller exhalation ports totalling 410.4 square mm vs the XStreams 8 more conventional looking larger ones totalling 484.6 square mm, so theoretically the XStream should have 15.3% less exhalation resistance esp at depth where the gas is much more dense. Maybe that's why the XStream passed the 200m NORSOK U-101: 2013 Diving Respiration Equipment Standards when the Jetstream apparently didn't?

Are the bubbles smaller in the Jetstream due to the reduced size and increased number of vent holes?

I think it may also come down to the difference between the Jetstream's coaxially positioned intake/exhaust diaphragms vs the separate planar intake and exhaust diaphragms on the XStream combined with surface area of the diaphragm exposed to ambient water pressure vs the contact footprint of each exhaust valve? Complex...

Xstream is is a little worse exhale wise. The pressure inside the case is less than the pressure at the exhaust valve, because the servo is controlled by the inhale diaphragm which is shallower, in the normal diving position at least, meaning one has to make up for this pressure discrepancy manually. The Jetstream does this coaxially like the old scubapros, keeping things nice and balanced pressure wise. That's my take anyways.
I don't think the exhaust valve size is a significant factor beyond a certain size, the bigger it is the more water works against it. Male trachea is only 300-350 mm2. The lack of exhaust tees/chimneys might be the main reason side exhausts don't breathe out so well. It never bothered me I've always been much more sensitive to inhale effort and consistency, especially at depth on air. Which the xstream/jetstreams deliver in spades.