First Stages Johns Quick Tip’s: First Stages Piston Un-Balanced This is the simplest of first stages. They are commonly seen on argon and oxygen systems. They are not ideal but they are affordable and your average person can rebuild them themselves. Piston Balanced or Diaphragm I can only give you my opinion here. I am a diaphragm guy. They are easier to work on and easier to adjust the intermediate pressure. The one thing you here from piston guys is that the piston reg flows more air though the first stage. This is true but you also have to be realistic here. A diaphragm will do about 50 to 60 cubic foot a minute though a port. A piston reg will do about 70 to maybe 80 so in the real sense, yes a piston is higher performance. So if you plan on breathing an aluminum 80 in one minute you are going to need a piston reg J Oh crap I forgot that all high performance second stages limit air flow so I guess have that piston reg really only does so much. Seriously though buy a diaphragm or a piston reg if you are happy that is all that matters and either reg will give you years of service.