janneau:
I have a new Atomic B2. My past experience was with a Tekna 2000 (old!) servo-assisted regulator that breathed with very little effort.
Before purchasing, I had read several reviews indicating that this regulator improves with depth. After roughly 20 dives with it, I found my experiences match this perfectly! It is utterly unremarkable at the surface, say for example on the showroom floor. In fact, when dry my backup Axis MR12 gives a better impression. So unremarkable, in fact, that when dropped into the water while floating at the surface that nothing happens. No enormous freeflow like my old regulator, usually accompanied by embarassed looks. It just kinda sinks and fills up with water, even with the mouthpiece pointing up.
When just under the water, a bit of resistance is felt. Not a lot, though...just breathes like an inexpensive regulator.
Below about 15fsw, though, all traces of resistance vanish, almost as if a switch has been thrown. Atomic says this is a depth compensating "Automatic Flow Control". And below this depth, the deeper you go, the better it breathes. A good description is that for me, the B2 is "transparent"; it has been like breathing without a regulator. When returning to the surface, I almost do not have to look at my depth gauge to know when we get to safety stop depth, the return of the flow control to "surface" mode is a noticeable change from the performance at depth.
So, I love it! A regulator that behaves at the surface, and breathes fantastically at depth.
Other things: I have had bad experiences with second stage swivels in the past, and was prepared to dislike the one that comes on the B2. The one on the B2 has a limited throw, so the 2nd stage doesn't end contorted into wierd positions (my past gripe) and actually "hardens up" a bit when the reg is pressurized, so it isn't floppy. Cool.
The 1st stage has a swivel turret with all the LP ports. I would have preferred to sacrifice this for a smaller 1st stage, and it's possibally a maintenence issue for the future, but there it is. It does fit swivel-down on every tank I've come across, though, (even some with pretty short valves) so it has less chance of banging your head.
The seat-saving feature on the second stage has been both a blessing and a curse. A blessing, because my hyper-sensitive servo regulator would end up hissing constantly because of a dented seat. More parts. So I like this about the Atomic. However, only about a third of the time am I able to fresh water rinse a reg while still connected to an air source on most day boat dives. So, with the seat pressure released, this could be a entry point for water, and I find myself only rinsing the outside of the 2nd stage because of paranoia. Of course I hook it up to pressure and rinse it when I get home, but this is an extra step and usually a day or two later.
The breathing resistance knob actually makes a difference. Wow!
I tried quite a few regulators before settling on this one, and I'm extremely happy with the B2. Like so many things, try before you buy with your hard-earned dollars.
All the best, James
