Upgrading AL DA Aqua Master

[Luis H]

Comparing a DA Aqua Master to a Royal Aqua Master (or a Phoenix Royal Aqua Master), I totally agree with what Nemrod already said. I will just add the following.

As mentioned the unbalanced diaphragm design will breath easier at the end of the dive than at the beginning. You are very familiar with the unbalanced piston, the diaphragm IP change is reversed and if I recall correctly it tends to change more than an unbalanced piston (like the MK-2).

Unbalanced regulators are designed with smaller volcano orifices in order to reduce the IP swing with the change in tank pressure. This means that in a high flow demand condition they will probably deliver the needed flow, but the IP will drop and will take longer to recover between breaths. In most relaxed diving situations the difference may be small, but there is a difference.

The larger orifice of a RAM does show a difference with the IP recovery from the normal IP dip during the inhaling cycle.


In the design of the latest Phoenix (Mod II, 2007 and newer) I enlarged and stream lined the air passages from the volcano orifice all the way to the port feeding the second stage. Due to the lack of precise instrumentation I can't fully confirm my findings, but from the limited testing and observations it seems to also perform better than I first expected.

The intermediate pressure recovery during inhalation is much quicker. In my primary Phoenix I have actually lowered the IP back to 135 psi (I normally used 145 to 155 psi) and it is performing as good as with the higher IP.


As Nemrod mentioned, a well tuned DA can be a very good performer and give a very good idea of how a double hose performs, but with a RAM you can really push the limits in performance.

With a RAM you a capable of tuning it so precisely that then you need the slits of the duckbill to be right in the center of the diaphragm or you will get small free flows when the exhaust is just higher than the diaphragm. A DA is seldom stable enough to push that kind of limit and then it will only happen with low tank pressure..


If you read some of the early evolution of the Phoenix, you will see that the addition of the ports was later. The original purpose was to make just RAM nozzle to be able to convert DA to RAM. Parts for the RAM will be around as long as Aqua Lung is around and the performance is the best.

 

[halocline]

I knew about the rising IP throughout the supply range, and the improved IP recovery makes sense. I guess when I get the reg I'll see if the 1st stage is working as is so I can try it out, but if I have to buy a replacement HP seat ($45) I might as well just go straight to the phoenix. I'd be pretty surprised if I didn't enjoy diving the double hose enough to convert the reg.

 

[Luis H]

You can probably resurface the seat before you need to replace it. Resurfacing DA seats is almost standard procedure (now-a-day) in servicing a DA.

Also, even if it has a slow IP creep, you can still use it if you just want to test it as is. If the IP is fairly stable you may want to just dive it as is before you open the first stage. You can service everything else. A slow IP creep is fairly common, it sometimes comes and goes (even with a new seat).

In order to check the IP you are going to need a hookah adapter port. The new adapters look close enough to the original caps, that I just replace all my old caps and only use the adapters even if I am not using the port.

 

[Nemrod]

There are some tricks with tuning a DA. Captain is a DA man. Several people use them as their go to regulator. In most diving, the difference between a DA and a RAM is not so noticeable. The thing is that some of the regulators that some of us are diving perform considerably beyond what they did in their first lives.

I will tell you this, if you never have used a double hose before, ever, then I could probably put you on my PRAM, my best one, and you would probably be disappointed. There is a transition time, you have to give it a bit to begin to appreciate the differences, the positives and the negatives and to acclimate yourself and I must say, you will have to change to some degree the way you dive. I kind of for example, swim very slightly rolled to the side, one way, then the other and I time my brweaths to coincide. I kind of sometimes use a flutter with scissor or a frog with scissor kick. I breath in with the scissor as I turn slightly to the side. It is natural to me since my old instructor taught me the side swimming thing before I ever knew the why of it so long ago. The controlled breathing is not skip breathing but it is why more than one or two divers have found, I simply use very little air. A long and slow exhalation follows during the flutter or frog portion of the kick. I can cover a lot of ground at surprisingly good speed this way without tiring and maintaining good breathing control, it also helps to control bouyancy, breath control is a key to good bouyancy control.

Oh dear, whats this, Nemrod with a single hose on a LONG hose, oh my, say it isn't so. Oh, wait, my wife in the back ground in her ancient poodle jacket is loosing her weight belt, must quit playing with the camera and go save her, again .

Oh, yeah, why roll to the side slightly when I inhale, so as to drop the diaphram in the water column to more nearly the center of my lungs.

N

 

[halocline]

I had kind of assumed that I'd need some sort of adapter to check the IP. Since I'm sure I'll change some soft parts before I dive it, I can just get the adapter at the same time. What are the threads for the hookah port?

I'm sure there's a learning curve to diving with double hose regs, but that's part of the fun.

 

[Luis H]

I had kind of assumed that I'd need some sort of adapter to check the IP. Since I'm sure I'll change some soft parts before I dive it, I can just get the adapter at the same time. What are the threads for the hookah port?

I'm sure there's a learning curve to diving with double hose regs, but that's part of the fun.

Here is the adaptor you need:
CHROME OCTOPUS ADAPTOR [Hookah Chrome] - $15.00 : Vintage Double Hose!, Your online source for all things related to vintage diving


Learning to dive with a double hose is definitely part of the fun.


Wow...poor Nemrod, not only is he diving with a crooked single hose in is mouth, but it is plastic.

 

[captain]

The hookah port uses a B oxygen nipple and nut available where ever welding equipment is sold.

 

[captain]

Being we are playing show and tell this is my double 72's and Pheonix with homemade aluminum back pack, deep outdoors wing, Seavue gauge, Farallon knife and Gerber shears.
I can prowl the depths of Lake Pontchartrain for several days with it.

 

[Nemrod]

Here is the adaptor you need:
CHROME OCTOPUS ADAPTOR [Hookah Chrome] - $15.00 : Vintage Double Hose!, Your online source for all things related to vintage diving


Learning to dive with a double hose is definitely part of the fun.


Wow...poor Nemrod, not only is he diving with a crooked single hose in is mouth, but it is plastic.

That is because I am using a DIR long hose arrangment and you see, I like to try stuff out before I judge it, lol, and that is one of the drawbacks, turn to the left and the hose wrapped around my neck pulls to the right, oh but for the joy of a twin hose . Can you imagine, some people actually dive with these single hose jobs and LIKE them, imagine that, go figure.

Nice outfit there Captain.

N

 

[rstofer]

Also, my Twin 50s, note dual regulators.

Are those 6.9" diameter Al 50's? If so, where did you find the bands? It turns out I have a pair of 50's that my grandson is using as singles. I bought them specifically for the reduced weight but, someday, they will become redundant to his needs.

Richard