Piston vs diaphragm... Balanced??

[herman]

So guys, can you mix and match first and second stages? Or is it best to put same brands together, ie. aqualung first and second stage? And if I have a Calypso first, do I need a calypso octo?

For the most part mixing is not a problem, I don't have a single reg that is not mixed. Posidens are a little different and you really should use a balanced primary second stage or at least and adjustable one on the "overbalanced" first stages due to the shifting IP at depth. Octos are not as much of a problem since they are normally tuned a little tighter in the first place so the extra few PSI of the overbalanced first at depth are not an issue, same holds true with seconds that have an external cracking pressure adjustment, if they start to freeflow slightly, just turn them in a little. Model names are totally unimportant, internally a lot of them are the same, at least in function and basic design. Many times they are the exact same reg with a different color faceplate or badge. Aqualung is big on that, the Calypso is the same as the Titan, the Titan LX second is the same as the Legend second and the Legend LX is nothing more than the Titan LX or Legend with a facelift and a few more bobbles.
The biggest issue is some service techs can't/will not service different brands, for us who DIY it's a non issue.

 

[ams511]

My LDS wouldn't even talk about the second stage regulator until he talked about how overbalanced first stages are the only good regulators (holding a $1200 atomic regulator).

You need to remember that the dive shop is a business and that more expensive items have a higher margin. So if he sells a $1,200 regulator he may make $600, if he sells you a $600 regulator he may only make $300. When I say "make" I mean the difference between the wholesale and the retail price. The shop still has overhead to cover. So maybe the dealer is trying to "compensate" for his rent payment coming do. lol.

BTW, Atomics differ only by the materials used to construct them, so a low-end Atomic breathes the same as a high-end. If it doesn't then it is probably a difference in tuning. Atomic regulators have a good reputation.

 

[Hatul]

What about the type of reg and the turret. Why are most turret regs of the piston type?

 

[herman]

I am speculating but the layout of a flow though piston makes it fairly easy to add the turrent on the end of a reg so why not as a selling point. Also, if the ports were in the solid end of the reg, it would create a manuf nightmare to keep clocking of the endcap correct (where the ports end up when the endcap is screwed tight. I don't recall ever seeing a flow by piston reg that had a turrent. The old USD Calypso J (flow through piston) originally had a single outlet but the later ones had multiple LP ports in a turrent. The Apeks style diaphgarm regs often had turrents, again a guess but that design layout makes adding a turrent easy so why not. The basic layout of most other diaphgarm regs makes multiple radial ports around the body easier than adding a turrent.

 

[halocline]

SP has produced flow through pistons without the turret; the MK9 is a MK10 without the turret, and ironically usually gets a higher price on the used market.

Personally I love the simplicity of the MK5/10, but truthfully there is no significant advantage between "piston" and "diaphragm" as such. It's a simple matter to pack the ambient chamber of a MK5 or 10 with grease and you have a very good cold water reg. The best examples of either type of 1st stage are fantastic regulators that have decades-long track records of success and are widely imitated. The poorer regs of each design are a PITA. Like the sherwood SR1; another irony considering sherwood's many years of making bullet-proof flow by pistons.

So it doesn't matter. The REALLY IMPORTANT thing is that the Spurs are heading to the NBA finals after 6 years. Actually, I might have a MK5 that I haven't rebuilt since the last time they won.

 

[elan]

I find the pistons are much easier to clean in case of flood. For that reason I use them on stages.

---------- Post added May 28th, 2013 at 06:06 PM ----------

Adjustability of the stage ha nothing to do with balancing. Adjustability gives you option to adjust venturi or cranking effort. Venturi should be lessened on the surface to prevent freeflows and cranking effort is often adjusted to eliminate freeflows while heading into the current or if the reg is used as a backup to decrease sensitivity and minimize freeflows.

So if someone has a balanced first stage, why would they need to have an adjustable second stage? Isn't that a little redundant, or counter productive?

 

[fnfalman]

My LDS wouldn't even talk about the second stage regulator until he talked about how overbalanced first stages are the only good regulators (holding a $1200 atomic regulator).

You can buy a $400 Atomic regulator and it will perform just as good as the $1200 Atomic regulator. The difference is that the cheaper Atomic regulator is made out of chromed brass and zirconium instead of stainless steel or titanium.

 

[captainhook426]

Thanks everyone for your input.

 

[ams511]

Thanks everyone for your input.

Your welcome but you may be over thinking things a bit.

 

[captainhook426]

I do this.... ALOT