Pony bottle set-up question/mixing 1st and 2nd stage regulator brands

[spectrum]

With the dry bleed understood you just want to make sure the 2nd is tuned to the different 1st stage. It will be important that the second not deliver (lose) air in a current otherwise unintentionally.

Pete

 

[Akimbo]

Just be prepared for different low pressure characteristics of an unbalance piston versus any of the balanced designs. You will begin to sense increased inhalation resistance regardless of the second stage at much higher pressures, typically 300-500 PSI. Balanced first stages can deliver fairly high demand rates near to even below the IP. Performance at high supply pressures is near-enough not to be noticed.

This can be a good thing in that you get an early warning of low supply pressures, and it can be bad if you need to suck every last bit of gas out when everything goes wobbly. I would be inclined to keep the high-performance first stage on my primary and the ultra-reliable, simple, unbalanced, low-performance on my pony where it is less likely to see low supply pressures.

 

[diverdorr68]

Just be prepared for different low pressure characteristics of an unbalance piston versus any of the balanced designs. You will begin to sense increased inhalation resistance regardless of the second stage at much higher pressures, typically 300-500 PSI. Balanced first stages can deliver fairly high demand rates near to even below the IP. Performance at high supply pressures is near-enough not to be noticed.

This can be a good thing in that you get an early warning of low supply pressures, and it can be bad if you need to suck every last bit of gas out when everything goes wobbly. I would be inclined to keep the high-performance first stage on my primary and the ultra-reliable, simple, unbalanced, low-performance on my pony where it is less likely to see low supply pressures.

Your post reminded me of some training when I first started diving where I breathed down a 80cf to only 50psi to try to better understand what an out of air event feels like. I did that with a Sherwood Magnum as well. With about 12 or 13 breaths left effort increased little by little and irregardless of effort with 6 or 7 breaths left, the breaths were shallower and shallower. In the event I would be forced to switch to my pony, I think I would prefer to have that 'warning' in a situation where every piece of info/feedback becomes increasingly valuable.

Thank you Akimbo and Pete for sharing your knowledge.

 

[windapp]

Your post reminded me of some training when I first started diving where I breathed down a 80cf to only 50psi to try to better understand what an out of air event feels like. I did that with a Sherwood Magnum as well. With about 12 or 13 breaths left effort increased little by little and irregardless of effort with 6 or 7 breaths left, the breaths were shallower and shallower. In the event I would be forced to switch to my pony, I think I would prefer to have that 'warning' in a situation where every piece of info/feedback becomes increasingly valuable.

Thank you Akimbo and Pete for sharing your knowledge.

This is why I like a balanced first with an unbalanced second. You get a warning when you have about 20-30 breaths left (once you hit the ip). You have your SPG to tell you when you get to 500 psi.