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

[rscott9399]

Hello all

Please forgive my ignorance but i have not seen anything on the web that answers this particular question.
My wife and i are about to take our Padi Open water class in a few days and being a gear head with just about everything we do i am kind of wanting us to have our own gear.
We have already taken care of our personal gear.

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.

I cant seem to get a strait answer from people on the cause. I have been told by some that is because it was an unbalanced 1st stage and by others it was because it was a crappy 2nd second stage

I think this could be rather panic inducing to some people so i would just like us to have our own. I also (foolishly i admit) keep stumbling upon diving accident videos on you tube and i am sort of paranoid. I recently watched a video of a HP hose failure on a 10 year old while doing his open water training dives...
Makes me really want even more our own new stuff. As a pilot myself, i like NEW things when it comes to life support devices such as "airplane engines"

I have a little extra coin so why not?
I can spend more then $300 but dont want to spend $800 either.

I was looking at the scuba pro Mk11/560 combo and also the Mk11/C350 Combo
I really like the slim design and look of the C350

However, (now im finally getting to the question part... Sorry)
I see that the C350 is "downstream" and not a balanced second stage
What does this mean exactly? I have found much info on the difference between diaphragm and piston balanced and unbalanced 1st stages but cant seem to find much info on the difference between the 2nd stage balanced and unbalanced.

Can someone explain? I know everyone has a favorite brand so im also open to other ideas as well.
Thanks in advance. I will continue to and have been looking at millions of gear posts on here also.

Thanks!

 

[Diesel_Diver]

....

 

[Lorenzoid]

Find this one? Balanced vs Unbalanced Regs: Does It Make a Difference?

 

[rscott9399]

Find this one? Balanced vs Unbalanced Regs: Does It Make a Difference?

Yes sir, thanks

I had seen that before but it does not mention what a down stream is.

 

[Lorenzoid]

Upstream or Downstream

It shouldn't be a concern in selecting a regulator. All modern regulators work just fine for most divers. After that, it's splitting hairs. There is a lot of hair-splitting on SB. I have yet to read a comment in which someone says he regrets having purchased brand X regs because they are difficult to breathe in the water.

If you had a bad experience, it was almost certainly because the reg was not adjusted properly. (Or possibly because of some idiosyncrasy of snuba that I'm not familiar with.) If a reg is serviced regularly, it will work fine for just about all of us.

 

[tbone1004]

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

 

[Lorenzoid]

As an aside, I would defer the decision to purchase regs until after the certification class.

 

[rscott9399]

As an aside, I would defer the decision to purchase regs until after the certification class.

Curious why you say this?
Always open to new opinions and thoughts.

I think watching that video of the kid with the reg failure on a rental has scared me for life and is making me want my own lol

 

[rscott9399]

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

Yikes, definitely going to need some time to digest all that

 

[tbone1004]

Yikes, definitely going to need some time to digest all that

enjoy! as a pilot you should be used to digesting information like that so I wrote it a bit more in line with that background vs. someone unfamiliar with mechanical things.
Any clarifications, please ask.
Out of curiosity, why did you settle on those two regulators that you mentioned?