picking out first reg and question about a "balanced" second stage

[BoltSnap]

here goes. This is long and relatively in depth, so any clarifications, please ask.

There are two types of valves used in scuba. One is downstream, the other is, you guessed it, upstream

Downstream valves are held closed by a spring that counteracts pressure from the opposite side. In this case the air pressure from the first stage *intermediate pressure* is pushing one way, and a spring is pushing against it. The spring pressure is greater than the air pressure under normal circumstances so it doesn't freeflow. When you inhale, you create a vacuum inside of the body of the regulator and a flexible diaphragm presses on a lever. This lever backs the spring off of the seat and allows air to flow into the chamber.
As long as you are creating a slight vacuum inside of the case that causes the lever to remain depressed, it will flow air.
In the event of a first stage failure, the pressure coming out of the first stage will increase. When the pressure of the air exceeds the pressure of the spring, the second stage will freeflow.
This is the most common type of regulator design used today as it is very simple to produce and incredibly reliable

Upstream valves are closed by the pressure of air behind them and require a certain amount of pressure to stay seated. What you create the vacuum inside of the chamber, there are two ways to release the pressure. The simple way is to have that lever push against the incoming air pressure and allow it to flow through. This type of valve is not really used in SCUBA though is used in some solenoid designs for rebreathers. The downside of this is that you are breathing against the air pressure that is keeping the valve closed and as that IP increases, the work of breathing increases.
The complicated but fancy and brilliant way is to use a servo valve that is really tiny which releases pressure behind the seat and allows the air to flow through. The Poseidon Jetstream and Xstream use this design principal and while it is unique, it is also incredibly simple with almost no moving parts and breathes incredibly well. These regulators have an overpressure relief valve built into the first stage that will bleed off excess IP in the event of a first stage failure so you can breathe off of the regulators normally. Since the OPV can't induce a freeflow, it will blow off less gas than a normal downstream second stage that may have a runaway freeflow in the event of IP creep.

In the downstream valves, there are balanced and unbalanced regulators. Traditional unbalanced regs are very simple, very reliable, and breathe very well so long as they are tuned specifically to the first stage that they are being paired with and they don't really deal well with changes in intermediate pressure. One way to make the work of breathing easier is to allow the intermediate pressure to go to both sides of the seat and use a very light spring to set the cracking pressure. Under normal operating conditions, in a pure balanced first stage *IP does not change at all*, then you should not be able to tell a difference between the two. Unfortunately first stages are not perfectly balanced and they do not perfectly maintain IP throughout use as the seats take a set etc. The balanced second stage will typically maintain breathing performance under changes in IP that would either cause an unbalanced second stage to freeflow or start to breathe a bit stiff.


Orientation for breathing performance: when you are in a "normal" diving position, the inhalation diaphragm of the regulator is facing downwards. Air wants to rise when in the water and this naturally helps to assist you in breathing. You have noticed this if you ever place a regulator in the water with the mouthpiece up and it induces a freeflow. You can also loosen your lips around the mouthpiece and it will start to flow. When you rotate and the diaphragm is vertical in the water column, this "assist" isn't really present and gets worse when you roll on your back since you are now sucking down against the diaphragm. This is something that is present in all regulators though some are more sensitive than others.

In terms of regulators on the market now. I dive Poseidon Jetstreams and believe that they are the best regulators on the market for me. I enjoy the way they breathe, many do not. They are not difficult or expensive to service, and Poseidon teaches a course to allow you service them yourself as well as purchase parts directly from Poseidon. They are not cheap, but they are truly incredible pieces of engineering. The Xstream is one of the smallest yet highest performance regulators on the market and has been certified for 200m depth by Norsok for commercial diving in stupid cold water.
DGX Custom - Poseidon Jetstream Single Tank Reg Package
DGX Custom - Poseidon Xstream Single Tank Reg Package

In terms of a more "normal" regulator that you will look and behave normally, the Deep6 regulators are truly hard to beat. Bit less than $600 out the door for a full regulator set that is ready to dive. First set of parts kits are included for free, first service is free *less the cost to ship back to Georgia*, and they will have a class coming out soon for you to learn to service them yourself if you are into that.
Deep 6 Signature Single Tank Regulator Package - Regulator Packages - Regulators
I would recommend that if purchasing two sets of regulators, that one of them be a doubles regulator package. This will give you a spare first stage which is convenient for use if you progress into technical diving, choose to use a pony, or the real convenient bit is that if you have one of the first stage failures as mentioned above, you have a spare. In less than 5 mins you can have the hoses swapped over and not miss a dive or have to rent regulators.
Deep 6 Signature Double Tank Regulator Package - Regulator Packages - Regulators

One incredibly important piece of equipment that every diver needs to own and know how to use is an IP gauge since that is what can predict first stage problems and ultimate failure. Only real way to tell that something is wrong or about to go wrong unless it is leaking. They are available from DGX and I uploaded a video to youtube a few weeks ago on how to use them

Come on @tbone1004 , this extremely long winded attempt to explain the difference is nothing more than a prelude to a plug for your own peculiar preference and bias in regulators and doesn't address what OP wants to know or actually needs. It is all skewed to drive the reader to just buy into the regulators and specific set ups you want.

 

[BoltSnap]

Valid point there above. Who knows what my goals may be in the future
I suppose part of my eagerness to buy our own stuff is strictly paranoia and no trust for rental companies of damn near anything.

I think i have picked a reputable place for our training but who really knows right? I just hope they provide some quality decent equipment.
but that was the main motivation to buy now. and for around $1k a person i figured why not? not that i have money to just burn but i am not afraid to invest a little either

If you can afford to buy your own equipment, or at least the primary/critical equipment, go ahead and do it. Rental equipment, especially at touristy destinations, is crap and there is nothing to gain to try different equipment in rental fleets. This is a myth that doesn't serve the diver at all. All he is going to try is crap rental equipment.

 

[boulderjohn]

Hi!

I don't know where you are from in Colorado, but if you are near me, I will be happy to meet with you and talk about gear. I am not affiliated with a shop, so I can give you information that is not colored by the need to sell any specific gear. I will tell you that the first shop I worked with adopted a policy of identifying specific items of gear to which customers were to be pushed. I worked with a student who had bought a full set of gear from them, and he was unhappy with it all. He started to tell me what he had bought, and I stopped him and finished the list for him. The shop had identified those items because they had the best profit margin, and all employees were to direct students and customers to those items. That is the main reason I left that shop.

You have already gotten the most important piece of advice: the gear used by advanced divers is usually no more expensive than supposed beginning gear, and it is just as easy to use--or easier--than the supposed beginner stuff. I am a technical diver who regularly dives in the 300 foot range, and I am sure the regulators I use are not as expensive as the ones suggested to you.

 

[rscott9399]

Hi!

I don't know where you are from in Colorado, but if you are near me, I will be happy to meet with you and talk about gear. I am not affiliated with a shop, so I can give you information that is not colored by the need to sell any specific gear. I will tell you that the first shop I worked with adopted a policy of identifying specific items of gear to which customers were to be pushed. I worked with a student who had bought a full set of gear from them, and he was unhappy with it all. He started to tell me what he had bought, and I stopped him and finished the list for him. The shop had identified those items because they had the best profit margin, and all employees were to direct students and customers to those items. That is the main reason I left that shop.

You have already gotten the most important piece of advice: the gear used by advanced divers is usually no more expensive than supposed beginning gear, and it is just as easy to use--or easier--than the supposed beginner stuff. I am a technical diver who regularly dives in the 300 foot range, and I am sure the regulators I use are not as expensive as the ones suggested to you.

Hi John!
Or i assume its john
Im in Denver. I would love the opportunity to chat with you and get some unbiased information. As you can imagine my wife and I have been to the usual suspects as far as dive stores in Denver go.
I can shoot you over a PM

 

[BoltSnap]

atomic B2

The Atomic B2 is in a different class, very high end, and is known for its best breathing characteristics and most reliable design and materials used in making it. If you get the sealed version, you will be getting probably the most reliable all around regulator in addition to having the best breathing characteristics out there.

 

[2airishuman]

I think i have picked a reputable place for our training but who really knows right? I just hope they provide some quality decent equipment.

Be careful. No doubt they are quality and reputable. They also make money on commission (or margin if the shop owner) and that may color their advice.

My first reg set was a HOG D1, and I paid around $500 I think all together (1st stage, two 2nd stages, spg, hoses). My other sets have typically been about $250 including parts, but I buy them used and service them myself. They're all Aqua-lung Conshelf XIVs. I have several sets because my kids dive with me, and because I sometimes dive with multiple cylinders in various configurations.

I dive "primary donate" with the secondary on a neck bungee, which I believe to be the best configuration in nearly all circumstances. The air integrated inflators are OK but have certain drawbacks.

 

[BoltSnap]

Be careful. No doubt they are quality and reputable. They also make money on commission (or margin if the shop owner) and that may color their advice.

The conspiracy theory again, these evil professional people who are trying to make a quick buck by being expert professionals and giving advice and guidance to their clients.

 

[OkByMe]

I think the suggestion of not buying anything until AFTER you get through training and a little more experience is well founded. There is a great volume of gear out there that can be perplexing to sort though. The best way is to rent what you think you like and try it out in conjunction with other gear. You will also be diving with people who carry spares and with a little persuasion, they will let you take a spare on a dive. You could also borrow a friends check it out... In most cases that is easy especially after them having bragged bout how good it is and the "wise" choice they made in purchasing it.

I have been diving a long time and have accumulated far too many regulators over the years, but for the most part, my alibi has been technological upgrades... At this stage of the game, after trying numerous regulators, I have finally settled on the brand I want, not only to simplify the parts count, but to know they all breath the same and I have the tools to maintain it. Scubapro MK25's with S600, G260, G250V, X650 is used on all my tanks. I trust all of these enough to run em' on bail out, decompression and recreational use. Note: the G260 hose can be mounted on ether side of the regulator... so if side mount is in your future, it can be handy. So buying from the jump without having the exposure to available gear, will tie up a bunch of money and potentially put you in the re-sale market.

Now to answer your question: I recommend the balanced second, get metal barrels. They don't ice and breath "wetter". All of the aforementioned seconds have them.

 

[rscott9399]

Be careful. No doubt they are quality and reputable. They also make money on commission (or margin if the shop owner) and that may color their advice.

My first reg set was a HOG D1, and I paid around $500 I think all together (1st stage, two 2nd stages, spg, hoses). My other sets have typically been about $250 including parts, but I buy them used and service them myself. They're all Aqua-lung Conshelf XIVs. I have several sets because my kids dive with me, and because I sometimes dive with multiple cylinders in various configurations.

I dive "primary donate" with the secondary on a neck bungee, which I believe to be the best configuration in nearly all circumstances. The air integrated inflators are OK but have certain drawbacks.

Fortuneatley the place we are going is more of a training center. I asked them about gear and was told they dont sell much other then personal gear. So we are not planning to buy from them anyway. I was more looking at local stores in my state. But i got the exact feeling you mention from the stores i have been to. I felt like i was buying a used car. Was high pressure to buy this or that brand etc etc

 

[ams511]

I dont want to spend a lot but a few things i would like after a Snuba experience on a cruise is a reg that flows nicely. While doing a Snuba trip i was not able to tilt vertical in the water. The reg became very hard to breath from and was forced to look strait down the whole time.

Don't judge scuba by "snuba". Snuba runs on a lower intermediate pressure than scuba so they are not comparable. While the second stages may look the same the springs are lighter because of the lower pressure. Also as someone already pointed out gear in tourist locations is mostly crap and not maintained.

Most regulators (except for some Poseidon models) are downstream so the upstream downstream argument is moot.

Balanced regulators breath the same regardless of air pressure. Unbalanced regulators breath harder at lower tank pressures. The main disadvantage of balanced regulators it that they are more complicated.