History of Adjustable/Balanced Second stages
Posted: Mon May 29, 2017 8:40 pm
Hi All,
I'm curious about the evolution of user adjustable and balanced second stages. My first experience with such a second was with Apeks which has both work-of-breathing adjustment and venturi adjustment. I then noticed several other regs like HOG are practically identical, as if they are copies. I also have a ScubaPro 109, received as a gift, although not balanced, it has adjustable WOB. I just finished watching the VDH 109 service video and heard the comment about a balanced poppet option so I looked at the ScubaPro regulator timeline on ScubaPro's site and see that the 109 was from 1969 and balanced was from 1985.
Now there was the Dacor dial-a-breath which looks like an early venturi adjust for DH regs but I don't have any idea about early venturi adjust for single hose.
Where those the first occurrences of adjustable seconds? When did venturi adjust come into single hose seconds?
I'm curious about the evolution of user adjustable and balanced second stages. My first experience with such a second was with Apeks which has both work-of-breathing adjustment and venturi adjustment. I then noticed several other regs like HOG are practically identical, as if they are copies. I also have a ScubaPro 109, received as a gift, although not balanced, it has adjustable WOB. I just finished watching the VDH 109 service video and heard the comment about a balanced poppet option so I looked at the ScubaPro regulator timeline on ScubaPro's site and see that the 109 was from 1969 and balanced was from 1985.
Now there was the Dacor dial-a-breath which looks like an early venturi adjust for DH regs but I don't have any idea about early venturi adjust for single hose.
Where those the first occurrences of adjustable seconds? When did venturi adjust come into single hose seconds?