Using an unbalanced second stage vs. balanced second stage

[Liberty01]

As I could not get a new diaphragma cover for my second stage oceanic GT3, I used an Alpha 8 for a dive holiday. I got used to it after some dives, but I thought that my air consumption was much worse particularly on deep dives.
I have dived with rental gear with unbalanced second stages for years, but I haven´t done really deep dives then.
I never used the valve to adjust. Thus, I thought it would not make a difference.
What are the disadvantages of the unbalanced seond stage when it comes to deep dives and air consumption?

As I currently can´t get the spare part for the GT3, I would have to opt fot a new reg.

Cheers,
Liberty

 

[tbone1004]

no disadvantages and quite of the few of the real deep dives *the several hundred meters and deeper* are done on unbalanced second stages *Poseidon*.

The adjustment valve isn't what makes it balanced, it's the internal mechanism itself that makes the regulator balanced. The adjustment knob just allows you fine tuning and it is typically used to make the reg harder to breathe so it is less likely to freeflow.
I.e. when not using it, the knob is all the way in, when you are breathing, the knob is all the way out

if you noticed an air consumption or perceived work of breathing difference, it was due to the way the regulator was adjusted, not the mechanism of delivery

 

[fmerkel]

Technically, what tbone said. I've got some unbalanced 2nds that are great, and some balanced that aren't quite as good. Since I tune them myself I'm pretty certain it's design differences.

 

[tbone1004]

Technically, what tbone said. I've got some unbalanced 2nds that are great, and some balanced that aren't quite as good. Since I tune them myself I'm pretty certain it's design differences.

I definitely gave an over-simplified answer and design definitely matters, but it's nothing about being balanced or un-balanced that make them breathe like that. I.e. a scubapro 109 and a 156 when tuned properly are basically indistinguishable from each other outside of a breathing machine, but are identical in every way except the poppet design.

 

[ams511]

As I currently can´t get the spare part for the GT3, I would have to opt for a new reg.

I would look for a new dive store. Oceanic does not change designs all that often so another cover should fit it. If not, I would look on ebay for another second stage for parts. Why buy a new regulator unless you want one?

 

[Liberty01]

Actually, I could not find it on Ebay this morning.
The Oceanic dealer for Europe is in the UK now, in mid-August the cover was not available. Getting spare parts in Europe was not possible before my holiday. Even on ebay they were out of stock. Incredible. I bought the regulator in 2008, I never had a problem with it.

Best regards,
Liberty

 

[BoltSnap]

*the several hundred meters and deeper*

"SEVERAL HUNDRED METERS??? Did you mean "METERS" or "FEET"?

 

[tbone1004]

"SEVERAL HUNDRED METERS??? Did you mean "METERS" or "FEET"?

meters

 

[BoltSnap]

meters

What, where, who is diving to "several hundred meters" on OC?

 

[tbone1004]

What, where, who is diving to "several hundred meters" on OC?

not anyone now, but Sheck Exley took them to 250m+, Hasenmayer took them to 200m+, Nuno Gomes took them to 300m+ in 2005?

I guess couple hundred is better than several, but point still stands that depth has little to do with performance of unbalanced vs balanced

Gabr was using Apeks for his 350m dive? but he was associated with an Apeks dealer so that isn't surprising. They were also set up very different than when they come out from the factory so the over-compensation didn't cause freeflows. The bottom regulators would have been very uncomfortable to breathe at shallow depths