Regulator Roundtable Q&A

[Jim Lapenta]

In truth for most tech classes I am aware of, hoses. You need to have the right length hoses for what you are diving. I like rubber myself because the braided ones are too floaty and catch the little hairs on my neck. They also tend to take a set when stored coiled.

First stages? DIN preferred since a yoke assembly can be a snag hazard and will not fit some 300 bar valves. The DIN o ring is arguably more secure as it is trapped on the reg and not barely seated in the valve like a yoke set up. Sealed is better since you may encounter cold water.

Biggest thing is properly tuned 1st and second! I had a 15-20 yr old Sherwood Brut that breathed as good down to about 100 ft as my HOG and Oceanic regs. I set it up myself. It is now being used by a pool cleaner.

Second stages? Again tuned properly. Adjustable is nice but not a necessity. No cheap octo's. Both seconds of equal quality and reliability.

And other than able to route the hoses properly that's about it. You don't need 800 dollar regs for tech diving. If you have decent recreational regs (sealed preferred) you can set them up for tech. Change to DIN, put the right hoses on, tune them properly and voila! You have tech regs.

---------- Post added October 7th, 2015 at 05:00 PM ----------

Oh, you might need to have a shiny black, flat black, stealth, or super duper 007 dull titanium finish if you want to take classes with some shops. THEY JUST HAPPEN TO HAVE THOSE IN STOCK!

 

[halocline]

I believe some regulators have devices in the first stage to prevent water intrusion if submerged without being connected to a tank (e.g. during cleaning). It may not affect how much gas the things deliver, but I wish my regulators had that feature. Others come with swivels that reduce jaw fatigue. Supposedly, the Atomic swivels are safe (compared to aftermarket swivels that have a bad rep for breaking apart).

Maybe not a "major" change, but I think they are still valuable. I wouldn't consider either feature to be a gimmick, since they both address real problems the average diver might have with a regulator.

The auto close features are a gimmick IMO, they don't really accomplish anything that a dust cap won't, and in one of the designs (the oceanic) they place a ball-on-a-spring right in the inlet to the regulator. This is EXACTLY where you don't want any possible restriction or blockage. And, the auto close devices are not intended to permit soaking of the reg without the dust cap on, anyways. They don't provide an airtight seal in the way a good dust cap does.

A swivel for the 2nd stage is easily installed on any regulator hose, and as such can just as easily be used on a 30 yr old 2nd stage as on a new atomic.

There are lots of high performance 2nd stages around these days, but in general they have gotten smaller, lighter, and with stronger venturi assist, presumably to lower WOB numbers on test machines. There's a price to be paid for this in the feel of the second stage; air moving faster and reduced volume in the case means the air spends less time between expansion at the valve and traveling down the diver's throat. This results in colder, drier air and a somewhat less 'natural' feel to the breath. Of course, this is subjective, but to me it's not nearly as pleasant to dive with.

---------- Post added October 7th, 2015 at 04:49 PM ----------

So I have a question. If regulators are more alike then dissimmilar, what makes a regulator a tech regulator? When I started venturing into more advanced diving, I was required to have tech regs but never got a clear definition of what "tech" meant when it comes to regulators.

I don't really know either, except for the things that Jim mentioned; DIN first stage, hose lengths for specific configurations. There is an old tradition of cave divers preferring 2nd stages that have removable covers under water in case they get filled with silt or some other contaminant, although I have never once heard of a diver who actually had to take a 2nd stage apart and fix it in a cave.

There's also a tradition of using high performance regulators for tech diving, with extreme depth, the ability of the first stage to recover IP quickly is taxed. But almost any decent first stage will certainly do the job. Just imagine how many conshelfs and MK5s have been to the Andrea Doria.

 

[USdiver1]

Many of us who really understand how these things work still choose to dive with old inexpensive regulators (I paid $80 for a MK10/D300 that I use in technical diving) despite the fact that we could easily afford the less-than-one-dive trip expense of a new high end model. There's just not that much difference between them.

You've just published my M/O. I prefer the following regulators, all of which can be adjusted to breathe like champions and be fully maintained by the DIYer or your LDS:

1) US Divers Conshelf series - I most commonly dive a 1985 Conshelf SE (1/2" lp ports on the first stage), plastic second stage. Conshelf XII and XIV models also adorn my dive locker and get regular workouts.

2) Scubapro Mk 5 / R109 - a real work horse - 'nuff said.

3) AMF MR-12II - Heaven. Get yourself a Mares Abyss second stage diaphragm, and put a US Divers Conshelf cold water (Supreme) kit on the first stage and you are set to go Great Lakes diving. What a regulator!

Newer equipment be damned, these regulators will be around for another half century.

 

[seeker242]

1. There's no significant difference in cost or difficulty of service for piston vs diaphragm regs.
2. HP ports provide tank pressure, LP ports provide intermediate pressure, typically around 135 PSI.
2. No you do not need DIN for HP tanks. Modern yokes are more than up to the task. Some DIN valves are not convertible, and for those tanks you do need DIN regs.
3. Yes, orientation does affect breathing characteristics. This is due to geometry issues and slight differences in depth between different parts of the regulator that change with orientation.
4. Only first stages regulate pressure, meaning they allow a specific pressure to pass through the regulator, and hold back any additional pressure. 2nd stages are "demand valve" meaning they allow air to pass on demand. The term "poppet" is used differently by different manufacturers, but here's what all regulators have in common. The first stage has a valve that is open when unpressurized. When pressure from the tank enters the regulator and reaches IP, this valve is closed, preventing further air passage. The 2nd stage has a valve that is closed when unpressurized, or more importantly, when there is a pressure balance between the inside of the 2nd stage case and the outside. When a diver inhales, he reduces the pressure inside the case, which allows outside pressure to collapse the diaphragm, which pushes a lever that opens the valve and allows pressurized air from the hose to enter the 2nd stage, until the pressure equilibrium is re-established. Any pressure excess in the 2nd stage gets vented out the exhaust valve.

Thanks! I must have had a brain fart. Obviously the HP port would provide tank pressure as that is where an SPG is connected to. :chuckle:

Although, only the 1st stage regulates pressure? I'm still unclear as to how, if there is 135 PSI inside the 2nd stage hose, that you don't have 135 PSI shooting into your mouth when the valve opens.

 

[USdiver1]

The first stage brings the pressure down from the tank pressure (up to 3,000 - 4,500 depending on your fill) down to the approximate 135 psi over ambient pressure. The second stage takes the 135 psi down to ambient pressure when you inhale.

In truth you do have higher pressure air entering your second stage, but you only need enough air to fill your lungs, which are at ambient pressure, so when you stop inhaling, the second stage diaphragm moves out and allows the valve to close rather than providing too much pressurized air.

 

[uncfnp]

...

Oh, you might need to have a shiny black, flat black, stealth, or super duper 007 dull titanium finish if you want to take classes with some shops. THEY JUST HAPPEN TO HAVE THOSE IN STOCK!

Unfortunately this was definitely the impression I got from one shop.

...

There's also a tradition of using high performance regulators for tech diving, with extreme depth, the ability of the first stage to recover IP quickly is taxed. But almost any decent first stage will certainly do the job. Just imagine how many conshelfs and MK5s have been to the Andrea Doria.

Ok. This answers my main question, about performance.

So Din is pretty much a given but many yoke regulators can be converted. Hoses and routing, so maybe number and placement of ports. Interestingly, sealed or cold water capable never mentioned but then I only do warm water diving. Adjustable? Definitely got the impression that if it didn't come with knobs it wasn't tech.

 

[halocline]

Thanks! I must have had a brain fart. Obviously the HP port would provide tank pressure as that is where an SPG is connected to. :chuckle:

Although, only the 1st stage regulates pressure? I'm still unclear as to how, if there is 135 PSI inside the 2nd stage hose, that you don't have 135 PSI shooting into your mouth when the valve opens.

The pressurized air inside the hose expands into the 2nd stage case. As soon as the case is "filled" at ambient pressure, the valve closes. Since the output of the 2nd stage is at ambient, and it only opens under demand, the type of valve it contains is not called a 'regulating' valve, it's called a 'demand' valve. 'Regulating' valves are valves that allow a specific pressure (above ambient) to pass. It's really just terminology. The second stage does 'regulate' pressure in a way because it does take the IP air and deliver it at ambient. But most people just think of the 2nd stage as a demand valve.

Now, if the first stage fails to hold IP, it can send much higher pressure air to the 2nd stage. Almost all 2nd stages are designed as 'downstream' valves, meaning that they will open under increased pressure from the 1st stage. This results in a free flow, but also protects the hose from exploding.

 

[Centrals]

So I have a question. If regulators are more alike then dissimmilar, what makes a regulator a tech regulator? When I started venturing into more advanced diving, I was required to have tech regs but never got a clear definition of what "tech" meant when it comes to regulators.

"Tech Regulator"? What is that?
And what did you buy?
I started with a pair of Apeks DS4 and with US1 and 4 as deco regs back in 1998. The DS4 is still being used but the US models had since been replaced with DS4 and DST.
I have also seen divers using MK 2, 11, 17, 21 and 25 for tec dive.
BTW, some divers would only use certain H brand regardness of its original.

 

[uncfnp]

"Tech Regulator"? What is that?
And what did you buy?
I started with a pair of Apeks DS4 and with US1 and 4 as deco regs back in 1998. The DS4 is still being used but the US models had since been replaced with DS4 and DST.
I have also seen divers using MK 2, 11, 17, 21 and 25 for tec dive.
BTW, some divers would only use certain H brand regardness of its original.

I ended up in sidemount for cave so a pair of MK25's with S555 seconds. All well loved by a previous SB owner.

 

[ams511]

No cheap octo's. Both seconds of equal quality and reliability.

It is interesting that there was an evolution here. In the past ( late 90s early 00s) it was recommended that your primary is a high-performance balanced second stage while the secondary is a lower-performance but more reliable unbalanced design. Now it is recommended that both seconds be high performance.