Adjustable or Non-Adjustable 2nd Stage?

[aacavalier]

So I am new to the whole diving equipment thing.....I am looking to purchase a regulator setup, but am very undecided on an adjustable or non-adjustable 2nd stage regulator. I don't intend to dive beyond 80 ft, and that depth probably won't be reached for a year or so. Probably will stay around 60 feet in moderate temperature water until I get a little more diving experience. I want to buy something that will last me a while and that I won't have to go out and buy more equipment later on if I decide to dive with Nitrox or just even decide to dive to 100 ft or so. What are the advantages and disadvantages of adjustable vs non-adjustable? Is and adjustable 2nd stage even worth it if I don't intend to really go beyond 80-100 feet?

 

[Akimbo]

The adjustable second stage, versus the venturi or deflector setting, is primarily useful when you are diving face-into a high current or riding a scooter/DPV (Diver Propulsion Vehicle). The adjustment allows manually increasing breathing resistance so the pressure of water flow does not cause freeflow. Unfortunately, a lot of divers don’t notice the difference and spend entire dives with the performance of a 1960s era second stage. Few divers ever needs it and many are hindered by it on modern regulators.

 

[aacavalier]

So, (if I understand correctly) water depth really has no bearing on the adjustment? It has to do with water movement? So basically, as long as I'm not swimming into a strong current or playing with a DPV, there is no real need to spend the extra $$$ on an adjustable 2nd stage! (Or am I misunderstanding that?)

 

[FWADIVER]

adjustable 2nd stages dont necessarily cost more $$$

 

[redacted]

I use adjustable 2nds for my alternates so I can have a high performance 2nd that can be detuned when not in use. Many of my primaries are also adjustable as that is a fairly common feature on high performance barrel poppet 2nds. While there are a number of high performance 2nds that do not offer a user adjustable feature like the Scubapro coaxial valve D-series, many non-adjustable 2nds are of the classic downstream design which tends to provide somewhat less performance than other designs. I often use classic downstream 2nds on pony and stage bottles where I don't really need the highest performance and the tank can be left off until it is needed.

 

[Seraphimx]

I second Akimbo.

When I bought my adjustable reg, I didn't know how to use it. I still don't fix it instantly, I fix it once I can take a small pause to adjust.
Therefore, If I look back, I'd take a non-adjustable and then buy other stuff first.

Depth does increase resistance. But not enough for a newbie like me to really notice it. At 90ft I do feel the difference, but in between .... not really.

In certain brands adjustable 2nd are more expensive.

 

[Zung]

I prefer adjustable even though I seldom touch the knob; I feel better knowing it's there if I need it. Plus it allows me to tweak the reg a bit more for easier breathing.

 

[Shftrdog]

Adjustable 2nd stages don't necessarily cost more. There are some inexpensive sets that have an adjustment, like the Oceanic NEO. There are a lot of options at all price ranges.

 

[LeadTurn_SD]

I dive both adjustable barrel-poppet (balanced) and non-adjustable classic-downstream 2nd's (unbalanced). So this is probably an even bigger contrast than the original question the OP asked.

My feeling is that basic design and tuning are of more importance than adjustable vs. non-adjustable, balanced vs unbalanced 2nd stages.

The difference in breathing effort between a well-designed & well-tuned classic downstream and an equivalent well-tuned balanced-adjustable regulator is very slight (at least among my regulators), and not enough to make me choose one reg over another on any given dive.

Also, I really cannot detect any change in performance with increasing depth with any of my 2nd stages, except that some (Mares Abyss) actually seem to breath better at depth?? Or maybe this is just narcosis....

The primary disadvantage to non-adjustable 2nd's is the inability to quickly "de-tune" them during a dive to prevent freeflows. Also, my adjustable 2nd's can also be tuned just a bit more "aggressively" since I can use the adjuster knob to de-tune them.... my non-adjustable 2nd's need a slightly more conservative "tune", but only slightly.

Best wishes.

 

[mathauck0814]

Do you have a need or reason to buy a regulator now? I'd say dive as long as you can before you make the purchase that way you don't end up buying it two or three times (you'll probably end up there anyway). Statements like, "I don't intend to dive deeper than 80 feet" have a way of becoming untrue - quickly.