This raises an interesting point. All adjustable (by which I mean effort adjustment knobs, not venturi boost levers) regs don't have the same range of adjustment. On some normal is in the middle of the range, so you can adjust in the field from free flow to sort-of-hard. On others normal is the easiest breathing postion, so the range is from normal-to-real-hard. Older Scubapros were like that. If you followed the official instructions, you tuned an adjustable G250 and a non-adjustable in exactly the same way, and the G200B with no adjustment would breath just like the G250 in the easiest breathing position.
Obviously, the former type is more useful since you can loosen the poppet way down for when the reg isn't in use to prolong seat life somewhat, as well as crank in a little positive pressure when you are working hard or stressed out. On the latter kind the main use of the adjustment is to eliminate any leakage that might happen after the soft parts take a set, and maybe to crank up the breathing effort for when scootering or busting surf.
The thing is, you don't have to twiddle with an adjustable 2nd for it to earn its keep.I like adjustments on 2nds. On a good reg you don't need the adjustments much, but when you need them, they are very useful. They also mean the tech can tune the reg more aggresively, since the any tendency to leak or freeflow can be dealt with by the owner.
With non-balanced regs they were even more useful. I used to regularly give the knob on my SP 109 (old classic chrome 2nd) a half turn half way through the dive, to compensate for tank pressure changes.
BTW people who equate Mares lack of adjustment with being "automatic" are deluding themselves. Automatic to me means the thing does the adjustment for me - like a balanced reg! - not that it just doesn't permit any adjustment. Sort of the difference between a auto and fixed focus camera. The Mares regs have no adjustments, and aren't even balanced. It's amazing how much performance Mares has been able to get out of the design, but functionally the 2nds are identical to my 1970 Voit.
Originally posted by VTWarrenG
I personally have never seen a diver twiddle with an adjustment knob... but then again, I don't usually dive with folks who are new to regulators.
I've seen several folks get really into the marketing hype, though -- and they come on here and start discussions about the V.I.V.A. or whatever and how it's much better than so-and-so. I guess those are same folks that twiddle their knobs (tongue in cheek) underwater.
I have a ScubaPro MK16/S550 that I use on stages, and it's a nice reg. I don't think I've ever really even touched the knob, though. I set it wide open when I first put it together.
- Warren
Originally posted by VTWarrenG
I personally have never seen a diver twiddle with an adjustment knob... but then again, I don't usually dive with folks who are new to regulators.
- Warren
I've often heard of people using Odins for really hardcore cold-water diving.
