I'm looking at getting a second regulator setup up that I eventually plan to use with doubles. I currently use a sherwood blizzard first stage with two blizzard second stages. I'd like to buy just a first stage and use one of the second stages that I all ready have. I think I've decided on a scubapro mk20 din. Is there any real problem/concerns with mixing a first and second stage from different manufacturers. Thanks for the advice.
First stage-Second Stage Diff. Manufactures?
- Thread starter Bnscherm
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The only problem would be if the intermediate pressure is different between the two manufacturers. For instance if Sherwood 1st stages call for 150 PSI intermediate pressure and the Scuba Pro is 125 the Sherwood second stage may work but it won't work as well as it would with the higher intermediate pressure.
Actually, there is one other thing to worry about when making "Franken Regs". 
Upstream Vs Downstream. Posieden Regs use an upstream design. They have either a hose that will vent or a relief valve on the primary to do the same thing. There are no probs with putting a downstream reg on any reg, but the converse is simply not true.
BTW, adjusting IPs more than a few PSI will affect the performance of the primary regulator and sometimes signifigantly.
Upstream Vs Downstream. Posieden Regs use an upstream design. They have either a hose that will vent or a relief valve on the primary to do the same thing. There are no probs with putting a downstream reg on any reg, but the converse is simply not true.
BTW, adjusting IPs more than a few PSI will affect the performance of the primary regulator and sometimes signifigantly.
rescuediver009
Contributor
Scottri:
Uh, no. Sherwood regs have an operational range of about 130 - 145. As for Scubapro, I don't have the exact specs but they will also have a range. These regs do not have a single pressure to work at as it cannot always be obtained. The regs should be fine together.
Hope that answers your question.
Uh, rescuediver009, I said IF, not that Sherwood IP was 150, I was trying to make a point.
The IP range for almost all major manufacturers are either the same or overlap significantly, so it's a non-issue. (Except for the aforementioned old upstream Poseidon second stages.)
But for the best performance, the second stage needs to be tuned once it's attached to the first stage. This is true even when the two stages are from the same manufacturer, as the IP can vary somewhat depending on the adjustment.
But for the best performance, the second stage needs to be tuned once it's attached to the first stage. This is true even when the two stages are from the same manufacturer, as the IP can vary somewhat depending on the adjustment.
paulwlee:
Thanks for all the useful info everyone. I've always wondered about whether I should play around with the IP to fine adjust it. However, what are the charecteristics of a perfectly tuned regulator and how will I know if i've gone a little too high or a little too low. I'm sure on the extremes you would see a free flowing regulator with too high a IP and with a very low IP you would have a very difficult breathing reg (especially in a underwater headstand since the first stage is significantly shallower than the second). Just give me a feel what I should be looking for in an ideal situation. Thanks again.
PS. From my understanding the new poseidon regs are all downstream with a IP up to a max of about 180 psi. Does this sound fairly accurate?
rescuediver009
Contributor
Bnscherm:
From what I understand you are implying that you are goingto fine tune your regulator with IP adjustments. I would recommend you take it to someone who knows how to do it right.
And your poseidon estimate is about right.
wolves64t
Contributor
There is a difference betwen wanting to know how to do something and actully doing it. Just because I know how to change the oil in my car doesn't mean that I always do it. But it is nice to know what the mechanic is doing under there. Also as far as regs go how are you suposed to know if your reg is out of tune if you don't know what the symptoms of an out of tune reg are. I'm not trying to be argumentative I agree that life support equipment shuld be serviced by the pros. I'm just putting another point of view out there.
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