Piston vs. Diaphragm

[shrwdtech]

Okay... I know, I'm biased. As the Technical Support guy for a manufacturer, I am supposed to lean towards the stuff we make.

But, as far as the consumer is concerned there is absolutely no difference between a piston and a diaphragm first stage. They each do the exact same thing for you. And with the exception of a very few 1st stages on the market, they BOTH allow water inside them in order to balance for the increased pressure on the unit at depth. IF they did not allow for water to enter them, adding the ambiant pressure to the front side of the piston, your reg would breath worse and worse and worse until you'd be literally sucking air as hard as you could in order to breath.

Also, the #1 rated regulator for Cold Water conditions, and also the most popular one in terms of over all sales is a Piston Designed 1st stage. You can go to a very informative website and view some stats from an Antarctic Expedition that tested regulators in some of the most extreme cold water conditions on the planet. http://scilib.ucsd.edu/sio/nsf/ These same results have been used by everybody from commercial outfits to the US Navy to NOAA in deciding what units they will use.

But, for your question, the answer is quite simple. Neither is any better than the other. Find several regs at your local dealers that fit the price range you are comfortable with. After that, ask about a bit, (and get all these lovely opinions) read up a bit and purchase the item you feel is best for you based on what is important to you. All in all, with the exception of a few, we all make good gear that you will probably be happy with. It's the minor features and benefits that alter from one manufacturer to the next.

 

[redacted]

DA Aquamaster once bubbled...

The R380 is a balanced second stage and offers consistent performance with varying intermediate pressure,

I'm pretty sure the R380 a classic downstream design just like the R190. That is same guts in a smaller case.

But for a reliable, adequate performing budget regulator it is hard to beat the Mk2/R190 or, if you think the smaller 2nd is worth the extra $$, the Mk2/R380.

I don't believe SP recommends using any of its balanced 2nds with the Mk2. They probably would not realize their performance potential without the higher performance 1st stages.

 

[Gator Diver]

What is the difference between the two?
I plan to dive in Florida Springs, ocean water (less than 100ft),
and some travel diving. Which type would
you all suggest? D or P. thanks.

 

[shrwdtech]

Okay... I know, I'm biased. As the Technical Support guy for a manufacturer, I am supposed to lean towards the stuff we make.

But, as far as the consumer is concerned there is absolutely no difference between a piston and a diaphragm first stage. They each do the exact same thing for you. And with the exception of a very few 1st stages on the market, they BOTH allow water inside them in order to balance for the increased pressure on the unit at depth. IF they did not allow for water to enter them, adding the ambiant pressure to the front side of the piston, your reg would breath worse and worse and worse until you'd be literally sucking air as hard as you could in order to breath.

Neither is any better than the other for the average divers use. What I generally recommend is to find several regs at your local dealers that fit the price range you are comfortable with. After that, ask about a bit, (and get all these lovely opinions) read up a bit and purchase the item you feel is best for you based on what is important to you. All in all, with the exception of a few, we all make good gear that you will probably be happy with. It's the minor features and benefits that alter from one manufacturer to the next.

 

[docmartin]

you may want to look at the link below. this has been discussed quite a bit on the board. also do a search on apeks vs scubapro. you'll find some long exchanges and many of the arguments revolve around the piston vs diaphragm debate. the reality is there are a number of top performing regulators with each design. i would not base my buying decision on if it is a piston or a diaphragm unless you dive in extreme conditions such as contaminated water.

http://www.scubaboard.com/t31085/s.html

 

[LUBOLD8431]

shrwdtech once bubbled...
Okay... I know, I'm biased. As the Technical Support guy for a manufacturer, I am supposed to lean towards the stuff we make.

But, as far as the consumer is concerned there is absolutely no difference between a piston and a diaphragm first stage. They each do the exact same thing for you. And with the exception of a very few 1st stages on the market, they BOTH allow water inside them in order to balance for the increased pressure on the unit at depth. IF they did not allow for water to enter them, adding the ambiant pressure to the front side of the piston, your reg would breath worse and worse and worse until you'd be literally sucking air as hard as you could in order to breath.

Also, the #1 rated regulator for Cold Water conditions, and also the most popular one in terms of over all sales is a Piston Designed 1st stage. You can go to a very informative website and view some stats from an Antarctic Expedition that tested regulators in some of the most extreme cold water conditions on the planet. http://scilib.ucsd.edu/sio/nsf/ These same results have been used by everybody from commercial outfits to the US Navy to NOAA in deciding what units they will use.

But, for your question, the answer is quite simple. Neither is any better than the other. Find several regs at your local dealers that fit the price range you are comfortable with. After that, ask about a bit, (and get all these lovely opinions) read up a bit and purchase the item you feel is best for you based on what is important to you. All in all, with the exception of a few, we all make good gear that you will probably be happy with. It's the minor features and benefits that alter from one manufacturer to the next.

SO, I guess you work for SHERWOOD, huh???

Thats funny. FInd an article that supports your reg, and then hail it as the best cold water reg. Thats a bunch of BS.

That report had a bunch of piece of crap regs in it too. Very old test also...

WHen Howard and Michele Hall did their Antarctic expedition the team used Oceanic DX-4 first stages with an environmental seal, with ZERO problems. (howard and Michele were on RB;s). Thats a DIAPHRAGM reg...


Its more how you use it, and the care when diving in real cold water like that...

 

[shrwdtech]

Nice job. You OBVIOUSLY don't read all the posts here, otherwise you'd know that I don't make any bones about where I work, and offer opinions based on same.

But, you'd also notice that 90% of my posts are pretty fair and quite often manufacturer free or generic.

You just seem bent to toss out flames, which is fine of course. I am glad I don't have that kind of negative energy to waste on people.

My response is based TOTALLY on DEMA sales totals, and research by the US Navy, Norbert Wu's site, and an upcoming arcticle in a Worldwide publication that you'll have to keep your eyes open for, as I'm not allowed to quote it yet. It's a great and broad comparrison. Guess who wins?

Regardless whether you like it or not, (your choice, this is America, after all), the Sherwood Maximus IS the #1 selling regulator for extreme cold water conditions world wide. It's a known and researchable fact. Notice I'm not claiming to be the best, or the most wonderful, the Lord Almighty's choice or anything else. I'm not offering my opinion in any way. I'm not blasting anybody else for their choices and some of the choices of many of the people here are completely ridiculous.

For what ever reason, you seem to skip the fact that the paragraph prior to and after the one you seem bent to flame are pretty information and sales generic, answering the persons question. You also are totally 100% unaware that those nice RB's that Howard and Michelle Hall are using are functioning with... Guess what??? Sherwood Valves on them. How do I know. I just sent them a whole bunch of service parts for them. So, basicly, if you have an opinion, like everybody else, great. What ever.

It pays to have your facts in order before you go attacking other people. And if you disagree it's even more constructive to give an attempt to disagree like an adult. Unless of course you ended your post because your mom kicked you off the computer. Then that would explain a great deal.

Have a nice day regardless, and enjoy what ever gear it is you do choose to dive with.

 

[LUBOLD8431]

I have never read any of your posts before...

I didnt personally attack you, I attacked your tactics, I dont appreciate your juvenile comments.

First of all, I happen to like sherwood regs for some things.

Also, I dont live with my mom, I have my own place, and my own computer thank you very much.

 

[ew1usnr]

I don't understand the Sherwood Tech's comment "And with the exception of a very few 1st stages on the market, they BOTH allow water inside them in order to balance for the increased pressure on the unit at depth."

On a diaphragm reg, water will get "inside" as far as the outer surface of the diaphram. To me, that's still the outside. What's on inside of the diaphragm is the inside of the regulator. The diaphragm seals the outside away from the inside. On a piston regulator, water comes in contact with the metal (usually brass) cylinder walls that the piston slides up and down against, as well as the top of the piston.

In my humble opinion, unless the piston regulator has the environmentally sealed upgrade installed, a diaphragm reg is usually better for salt water diving because the water contacts a rubber diaphragm rather than brass cylinder walls and there is less potential for corrosion. Sherwood pistons are an exception among piston regulators, though, because their dry air bleed in the first stage keeps water out.

 

[ElectricZombie]

Both diaphram and piston regs work fine if properly designed. Diaphram regs are unable to achieve the high flow rates of piston regs due to the nature of the design. However, the only way to really tell the difference between a good diaphram reg and a good piston reg is to hook it up to a sophisticated reg testing machine. A human will not be able to tell the difference.

I have dove diaphrams and pistons and cannot tell any difference in breathing. I currently use two Mk25s (piston reg) and am very happy with them. If I were doing cold water diving, I would probably go with an Mk16 (diaphram).

Either one will perform fine since you are not doing any cold dives.