Hi folks- I have just received my new ST1 Atomic- and I stuck it on an old tank to test it out a bit prior to my first dive with my new toy. I have run into this before- and was a little put off to find that the 2nd stage trumpets on exhale... I guess the best way to describe it is that it sounds like a harmonica when I exhale. I unscrewed the cap, checked the diaphragm and all seems well with the assembly. As I said, I've had that happen with a lot of rental regs in the past- but I was really expecting smooth and effortless with this top of the line reg- What's the scoop? Don't worry about it until I've had it to depth? Send it back for one that doesn't "bark"? I guess I should be happy that the Zeagle Octo Z that I received in the same box is smooth and quiet. Sure would like to sort this out. Help!~
2nd stage "harmonica" at the surface
- Thread starter Osseous
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Fish_Whisperer
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CC1020
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My Apeks XTX-50 does that too, but i was told it's not a problem. Hope they were right...lol
vshearer
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Sounds like the exhaust valve is sticking. Check out this thread
Exhale or Inhale?? It fairly common for regs to buzz during inhale ABOVE water, nothing to worry about or "repair". The diaphram vibrates due to pressure pulses (short version of story), underwater the water damps the vibrations enough so they don't happen. ....If it's exhale...ya got me.
Inhale is slight, exhale is significant. I talked to the shop and they said it's normal until it is submerged- which doesn't make it any less annoying. I hate it when my regs do this- but was willing to tolerate it more with a cheapo rental reg. I'm thinking of returning the ST1 in favor of something else...
Arcaporale
Contributor
It sounds like the exhaust valve is reverberating as you exhale. This is based on the same principle as the harmonic resonance the occurs in piston 1st stages. Any reg will do this if you exhale at just the right rate. If you exhale with some force it probably won't make the noise. It's possible the exhaust valve is sticking slightly, try submerging the 2nd stage in water and breathing from it, it's likely it will stop. You mentioned you expected "smooth and effortless" exhalation, well if the exhalation does require any significant effort then there is something wrong with the exhaust valve. Don't let this situation put you off on the ST-1 it is an excellent regulator.
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My T2 did it for the first couple of days when new. It stopped after about 8-10 dives. I can still make it do it if I just barely exhale in exactly the right position when it's dry.
After you dive it may change your mind...they're effortless breathers in any position.
Dirkadiver
Contributor
I think just about all my regs have done this. Like others have mentioned, the DS & manufacturers both told me the same thing.....nothing to worry about as long as they don't start doing it underwater.
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