I want to put a Y manifold attachment on the acetylene tank so I
can have both torches hooked up at the same time, My little torch
set-up has dual stage.
There is a big difference between single stage and dual stage
regulators, however it's not the gauges that dictate the difference
it is in the internal workings of the regulator. In a nut shell a
two stage, or dual stage regulator will drop cylinder pressure to
working pressure in two stages and a single stage will do it in just
one. With the dual stage you get much better line pressure control
and very little, if any, line pressure fluctuation. Also a dual
stage has a much larger housing extending out from the tank.
But to answer your question, yes, either way you can hook up a "Y"
connecter and run your ambient air torch, however you will get line
pressure fluctuation if running both torches at the same time no
matter the type of regulator.
Hope this helps.
Rio Grade Technical Support