considering a double hose reg

[Scotttyd]

So after diving with Herman and his double hose, I am considering jumping into the vintage world. Although I have a few questions.
1. What is the difference between a two stage and a one stage reg? (other than the obvious). Does the two stage perform better? (does depth make a difference).
2. How important is a balanced reg? I have never dove with an unbalanced reg, and was curious as to what tank pressure does a difference become noticable?
3. If I desire - can you add a pheonix nozzle to all double hose regs?

 

[herman]

I will get to your email this evening.

1: A single stage regs drops pressure directly from the tank pressure to the ambient. The main advantage of a single stage is it's a much simpler design. A couple of levers, a spring, a push pin and a HP seat. Very little to fail and zero Orings to go bad. Performance is a subjective thing. Many DH divers like the single stage due to its reliability and the sound it makes when you breathe. Its main drawbacks are it is sensitive to tank pressure and there is no way to add any LP accessories- there is no LP to use. They do not breathe as good above 2500psi and considering the HP tanks of the day were 2250psi it makes sense but they breathe great from around 2000 to a fairly low tank pressure. They will work at 3k, just not as well. The USD Mistral and the Voit 50 Fathom are a couple of single stage examples. 2 stage regs like the DA Aquamaster (DAAM)and the Royal Aquamaster (RAM) are both 2 stage regs, they both reduce the tank pressure to an intermediate pressure (IP), exactly like your modern single hose reg does, then delivers it to you via a demand valve housed in the main body. The difference between the RAM and the DAAM is the RAM has a balanced first stage, exactly like Seans Titan (same parts internally) otherwise they are the same.

2. I don't see the balancing as that big of a deal, you can tell the difference but barely. Theoretically, an unbalanced DAAM will breathe easier as the tank pressure drops as opposed to the balanced RAM that will keep the breathing resistance constant. One difference in the DAAM as opposed to modern unbalanced regs is the DAAM will get easier to breathe from (as will the single stage regs) as opposed to the modern unbalanced piston reg which gets harder to breath from as the tank pressure drops.

3. The Phoenix can be added to US Divers DAAM and RAMs as well as the Voits of the same design (my Voit model number knowledge is limited). That said, I would not convert a Voit due to their collectability- they tend to run much higher than USD regs and in the same vain I would not convert a RAM. They sell for a good bit more. Plus the DAAMs are a lot easier to find. The good news is the conversion is non-destructive and the reg can be returned to original in a few minutes if you so desire. Other brands like Dacor and Healthways are not convertible and are hard to find usable parts for so they are best left hanging on the shelf until you are deep into restoration of regs

I have a Mistral, DAAM, RAM and a converted DAAM with a Phoenix (know by most of us as a Phoenix Royal Aquamaster - PRAM) plus a Faux Voit Blue 50 Fathom, all of which are restored and you are welcome to dive any of them.

 

[Scotttyd]

thanks herman, I can always count on good info from you.

two follow ups -
it surprises me an unbalanced reg gets easier to breath as the tank pressure goes down - how does that work? (since it is the opposite of how modern regs work)

Currently I only have 3442 psi tanks (four of them) so running out an buying more is not at the top of my priorities - how do the vintage regs do with the increased pressure? from what you say the one stage regs are out of the question, but I was unsure if the two stage regs would work at the high pressure.

 

[herman]

thanks herman, I can always count on good info from you.

two follow ups -
it surprises me an unbalanced reg gets easier to breath as the tank pressure goes down - how does that work? (since it is the opposite of how modern regs work)

Currently I only have 3442 psi tanks (four of them) so running out an buying more is not at the top of my priorities - how do the vintage regs do with the increased pressure? from what you say the one stage regs are out of the question, but I was unsure if the two stage regs would work at the high pressure.

Basically, it's the physics involved with opposing forces on the HP seats and the fact the old regs are diaphram stages as opposed to modern unbalanced regs which are all piston type, got to go to a class now so I don't have time for a long description. I have a couple of books on regs you should read, they will teach you everything you want to know about regs and then some.

You can always bleed some of the pressure off the tanks. I know you dive part (used) tanks at the quarry some anyway and I have some you can borrow if you need them. You could also use a transfer whip to split the tanks in half, large tanks at 2000 would do nicely. I would not press the old regs much past 3000 but the Phoenix mod should handle 4000 with no problems....or at least the yoke says it will and the guts are capable of it. Maybe Luis will chime in, he designed it....

 

[halocline]

I would say there is a very noticable difference in the breathing performance of a DA aquamaster and a RAM (Royal aquamaster) or PRAM. The difference is not so much in the increased breathing resistance at higher tank values. It's more that the RAM nozzle and HP seat just work a lot better IMO. The RAM nozzle has a higher flow and the seat has a more stable IP lock up; at least the few that I've owned and worked on do.

Other people might have a different opinion. My suggestion would be to get a DA and go right for the phoenix nozzle.

 

[Scotttyd]

I would say there is a very noticable difference in the breathing performance of a DA aquamaster and a RAM (Royal aquamaster) or PRAM. The difference is not so much in the increased breathing resistance at higher tank values. It's more that the RAM nozzle and HP seat just work a lot better IMO. The RAM nozzle has a higher flow and the seat has a more stable IP lock up; at least the few that I've owned and worked on do.

Other people might have a different opinion. My suggestion would be to get a DA and go right for the phoenix nozzle.

question,
you mentioned your suggestion is to get a da and add the phoenix, but then you state the RAM works a lot better ?? Are you suggesting to get a DA because of the price vs a ram, or the quality?

 

[Paladin]

Quality wise, there is no difference between the DAAM and the RAM. They use some of the same parts. The Phoenix valve essentially takes an unbalanced DA Aqua-Master and converts it to a balanced Royal Aqua-Master with a few accessory ports. Herman is right. There really isn't all that much difference in breathing resistance between the DAAM and the RAM. You have to really be paying attention to notice it. The RAM is more expensive to purchase than the DAAM

You don't have to go to the extra expense of a RAM or a PRAM (Phoenix Royal Aqua-Master) to get started in DH diving. A DA Aqua-Master with a banjo fitting (for an SPG), a long yoke (to accommodate the banjo) and an adapter to convert the Hookah port into an LP port would get you started. It's an excellent regulator and breathes surprisingly well. I have one and I honestly do not feel the need for the added expense of the Phoenix nozzle at this time.

If, later on, you decide you want to, you can get a Phoenix nozzle for the DAAM to convert it into a PRAM.

 

[Luis H]

You have already gotten some decent advice.

The only thing I would be careful with is using a DAAM with a banjo fitting on a 3442 psi tank, especially with a DIN convertible valve. It may work OK most of the time, but with the convertible valves it doesn’t always work well.

Also the higher the pressure, the worse a DA breathe. The first stage valve is upstream; therefore the IP is lowest at high pressure (as opposed to an unbalanced piston first stage).

Most DA Aqua Master can be adjusted to breath very well, but could never be fine tuned to the level of a RAM. The precision of the fine tuning that can be performed with the IP in a RAM can never be matched by a DA. Also a RAM has a larger volcano orifice which helps in IP recovery during the breathing cycle.

That being said, not everyone takes the fine tuning to the same level. I have seen some RAM that do not breath much better than a well tuned DA. Normally most people can’t tell a huge difference.

The earlier Phoenix will always perform the same as a RAM since the flow path is very similar to the RAM. The later two MODs can perform a bit better. MOD II and MOD III has been around for a few years and again most people can’t tell much of a difference, but they do have the potential for much precise tuning.

I improved flow path on these MOD’s in order to reduce the IP drop during the breathing cycle. The difference is small since it is hard to improve on a RAM, but if one takes the time for some precision tuning, it is possible to get a bit higher performance. I actually had to drop the IP a bit to reduce the sensitivity in my preferred MOD II Phoenix RAM.

I have some performance data of the later Phoenix RAM taken in Panama City at the dive lab that I should be sharing soon.



I am glad to see that you have Herman near you. He should be able to help you to get started. I am sure he can be a great mentor.


This is your best source for some of the technical information on double hose regulators.
You will see the difference and good descriptions of an Aqua Master, a Royal Aqua Master, a Mistral, etc.
Technical Information / Diver Training Information:
http://www.vintagedoublehose.com/forum/viewforum.php?f=12&start=0

 

[Paladin]

Listen to Herman and Luis. These guys know their stuff and will never steer you wrong.

 

[halocline]

question,
you mentioned your suggestion is to get a da and add the phoenix, but then you state the RAM works a lot better ?? Are you suggesting to get a DA because of the price vs a ram, or the quality?

Sorry, I wasn't very clear. The phoenix nozzle upgrades the DA to performance equal to (or slightly better than) the RAM. You also get ports and a modern yoke for about the same price as just buying a RAM. That's why I would suggest it.

I told you there'd be differing opinion, that's what makes this forum interesting. I bought two DAs, converted one to a PRAM, and directly compared them on a few dives. To me, there's a big difference. But you might not have the same experience.

Another excellent feature of the PRAM (and RAM) is that it uses current HP seats and nozzle parts. That seat is really good quality, and easily replaceable when necessary.