Vintage Double Hose

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?

Several single hose regulators had a diverter built into them....The 1085 USD and the Dacor line that I remember for sure but the first user adjustable I remember ever seeing was on a G250 in the 80's.

Im more curious who first developed the air barrel on the 109. Many are still using it today, but was it SP's idea, SP copy someone, or an accumulation of every manufacturer adding one improvement at a time.

Sent from my SAMSUNG-SM-J320A using Tapatalk

[quote="jvanostrand"]Hi All,


.... 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.

Dacor should have labeled the adjustment point extremes "bad" and "worse".

Well, technically speaking. Air intake control by the diver goes back to THIS:



My attempt at some diving humor.