Collectors list of notably easy breathing second stages?

[Kupu]

Thanks for the Poseidon explanation tbone, I get an idea of what is being described and think the best way to really understand will be to find a used Xstream and get it in the water. It looks like the Poseidon may be a better fit for the collectors list vs the Kirby Morgan.

Fibonacci, I have seen your discussion and pictures of Commander/Command Air internals, and really look forward to picking one up to play with when the opportunity presents itself.

 

[buddhasummer]

You can still get D series service kits.

 

[reefrat]

The Kirby Morgan Superflow metal second is certainly a very easy breather but only because it has diver adjustable cracking pressure all the way from a full free flow to tight. It is therefore possible to have it constantly adjusted right on the edge but it depends on the operator knowing what he is doing and paying a little attention to it.
Typically before I open the tank valve I turn the adjustment knob 2-3 turns back otherwise it will free flow, at this point it will breath fine and later when I hit the bottom and start the dive proper I will roll the adjustment forward until the reg starts to bubble slightly- then a fraction back and it is optimal. Later a diaphragm first will usually have a slight IP swing and the reg may start bubbling again when the tank pressure gets to about 1500 psi, I automatically adjust it again without thinking about it.
Obviously this is not a set and forget piece of equipment for the diver who just wants a reg adjusted by a tech that he never has to think about however it is still easy to use and I like it.

 

[Fibonacci]

Fibonacci, I have seen your discussion and pictures of Commander/Command Air internals, and really look forward to picking one up to play with when the opportunity presents itself.

I'll keep an eye out for a Commander, even here they are thin on the ground these days as 95% of dive shops won't service them saying kits are long unavailable with Sea Hornet's demise over a decade ago...

From time to time NOS sealed-in-a-bag gems come up as old dive shops close down, mostly DIN for some reason (I guess they never sold as well as yoke style back in the day and stayed in the store room).

Maybe we can do a deal, I'm after a chrome VOIT V66 Navy double hose reg like this
Voit Regulator | Vintage Double Hose

 

[Kupu]

You can still get D series service kits.

Thanks for the correction, seeing only older style SP D400/350 kit packaging on ebay recently caused me to forget and assume SP no longer made them. Glad to be wrong on that...

 

[JackD342]

I think this was touched on in a couple of posts, but to state it more plainly: cracking effort is NOT the only measure of "high performance." You also need the Work Of Breathing performance specs, which are more difficult to standardize across brands/items. They may all use an ANSTI machine to test, but do they all test with using same parameters? Often they do not.
Believe it or not, 0.8" cracking pressure is the lower end of the acceptable range for the Aqualung ABS octo, that lowest cost puck shaped octo. But I would NOT expect it to also be a high performing item. (WOB is not available for it, as that would be dependent on which 1st stage it is installed on. WOB is measured for a pairing, not for an individual 1st or 2nd stage.)

 

[Kupu]

I'll keep an eye out for a Commander, even here they are thin on the ground these days as 95% of dive shops won't service them saying kits are long unavailable with Sea Hornet's demise over a decade ago...

From time to time NOS sealed-in-a-bag gems come up as old dive shops close down, mostly DIN for some reason (I guess they never sold as well as yoke style back in the day and stayed in the store room).

Maybe we can do a deal, I'm after a chrome VOIT V66 Navy double hose reg like this
Voit Regulator | Vintage Double Hose

I see a complete Sea Hornet set available for $125 right now, but that too pricey. Especially since condition is average at best and I am only looking for the second stage. I will look around and keep an eye open for the Voit, maybe we can sort something out.

 

[Fibonacci]

I see a complete Sea Hornet set available for $125 right now, but that too pricey. Especially since condition is average at best and I am only looking for the second stage. I will look around and keep an eye open for the Voit, maybe we can sort something out.

OK if you are just looking for a good Commander second stage that may be easier... just remember you will need to pair it with a first stage IP set at 10 BAR (145psi) to get full performance.
Sure happy to sort out a deal if we can

 

[Kupu]

I think this was touched on in a couple of posts, but to state it more plainly: cracking effort is NOT the only measure of "high performance." You also need the Work Of Breathing performance specs, which are more difficult to standardize across brands/items. They may all use an ANSTI machine to test, but do they all test with using same parameters? Often they do not.
Believe it or not, 0.8" cracking pressure is the lower end of the acceptable range for the Aqualung ABS octo, that lowest cost puck shaped octo. But I would NOT expect it to also be a high performing item. (WOB is not available for it, as that would be dependent on which 1st stage it is installed on. WOB is measured for a pairing, not for an individual 1st or 2nd stage.)

Thanks, I understand and agree. I have made numerous comments and references to cracking effort lately, but do not mean to imply it is my stand alone definition of high performance. Even though the Pilot/AIR1/D series have notably low cracking effort, there are other factors that come together to allow them to breath so comfortably. It would be great to find more regulators offering exhalation that feels effortless.

 

[Fibonacci]

Another update from Peter Katz regarding the Command Air design process to reach a consistent 0.5" cracking effort:

"During the development of Command Air we conducted hundreds of tests, varying the angles and curvature of the lever, its length and leverage ratio.
Also the shape of orifice and spring tension. We also changed the size of holes and their position on Sleeve and Boost knob.
The final result of the performance of this regulator is therefore a combination of many attempts and changes throughout the development.
So I can't say which part was decisive or more important."​