2nd Stage Adjustments

[dmentia]

I was just reading some reviews about several regs that have been mentioned here quite often, and one of the reviewers brought up a point that I have been wondering about for a while now- if a regulator is designed well, and balanced well, why would they need to add a 2nd stage adjustment knob?

So my question is- Do the 2nd stage adjustments make any difference? Are they more for tech/deep divers, not recreational like myself who will rarely see 100 ft, much less beyond 130? The Oceanic Delta 3 and Apex TX50 both get good (great?) comments, and ease of breathing etc is always mentioned. Is this breathing after adjustments? Or are the adjustment dials rarely used anyway?

And a last question: For someone like me with no aspirations for tech, nitrox, deep, cave etc. diving beyond recreational diving, is there any benefit to going beyond a solid, dependable, simple Reg?

Thanks for any input!
dmentia

 

[rcontrera]

What a great question!!

In the early days of diving, an importer/salesman tried to market a cheap little piston regulator to the American diving market. That piston first stage did not do as good of a job adjusting for ambient pressure as the diaphragm regulators of the day. As a result, it breathed harder at depth. To overcome that, he had an external adjustment installed on the second stage. His marketing expertise was so great, that he convinced LOTS of divers and even a few diving companies that the little dial was necessary for a "high performance" regulator.

Today, first stages are nicely engineered and do a great job of adjusting for ambient pressure so the dial really isn't necessary. However, the marketing genius of that Italian import company still has many, if not most, of the divers believing that the funny little knob is really mandatory.

If you think about it, any regulator that has to have an external adjustment at depth, really isn't working right in the first place.

Just my $.02

Ray

PS - That little import company with the marketing genius is now called Scubapro

 

[neil]

You're absolutely right Ray!
I've had a US Divers rep tell me that the knob on the Micra Adjustable was pure marketing, and a Sherwood rep told me that probably the best use of the adjustment knob on the Maximus was to break any ice buildup!!
The knob on my TX100 never gets turned. Once the minimum cracking pressure is set, it's set.
As you say, only an unbalanced reg really needs an adjustment knob.
Neil

 

[mlove]

I have a micro adjustable. When I am on the surface
with the adjustment open it sometimes freeflows. I have
been leaving it set mid way and forgeting about it. I was never sure why I needed it. It is a nice weight and is comfy in my mouth.

regards,
M

 

[luvdiving]

One thing that's nice about the adjustment knob it it's ability to "de-tune" the reg. I use this feature when lobster diving in surgy conditiond on the reef. That helps stop the constant free flow I get when facing into a swell.
I love this site!

Thanks, Ken

 

[divekiwi]

Hi,

my Aqualung Impluse has an adjustment 'knob'.
I find it really handy if I'm diving in really rough conditions i.e. I can dial up a higher flow rate when my work rate increases significantly.

Usually I have mine dialled all the way down.

I think it was really just an excuse to charge more for the set.

I agree that if you've got a properly tunned reg, you don;t need the adjustment.

I subscribe to the 'more working parts' concept, more things to break...

my 2 pennith

________
divekiwi

 

[The Chairman]

Hey Dmentia & All,

Some good comments here, but I think the reason -I- like the adjustable regs is that the tech setting up my reg will do so to his/her taste. I like my crack pressure considerably lighter than most, so I use it a lot. As always though, do make sure to store your regs with the adjustment all of the way out... releives pressure on the valve and seat.

 

[neil]

NetDoc,
Most knowledgable techs, myself included, will adjust the reg so that it freeflows slightly when the knob is all the way out. That way you get the entire range of adjustment all the time. However, this is not the way most manufacturers specify the adjustment.
Neil

 

[The Chairman]

Hey Neil,

Do you do mailorder on reg rebuilds??? I would love to have someone set mine this way... My E-Mail is PJM@NetDr.cc

 

[gulfdiver]

The fine tuning knob allows you to breath at depth with virtually no effort. When I upgraded to the G250 from the R190 (no adjustment other than a butterfly valve), my air consumption dropped a bunch and bottom times went up.