Advice and opinions: Atomic B2 vs SP Mk25/A700

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Hello,

I'm a first time poster and starting to feel really out of my "depth" sorting out which regulator to buy. I think I have narrowed it down to an Atomic B2 or ScubaPro Mk25/A700. My dives will be warm water in Central Texas, the Gulf, and the Caribbean. Hopefully Overseas (SE Asia, South America) at least once a year. I have some questions that would help me narrow down my choice though any advice would be appreciated.

1. I've read on the SB that Scubapro has a worldwide network for service, does that provide an advantage to the vacationing diver who is there only for a week or two? (Quality of Service and quick turn around)

2. I have also read because of some feature on the Atomic rinsing the 2nd stage can be difficult, could you elaborate?

3. To any beach divers or central Texas divers should I be concerned about buying an piston first stage and "gunking" it up?

4. I have trouble with dry mouth and have heard that a metal barrel in the A700 alleviates this, does anyone agree and does the Atomic exhibit similar qualities?

Thanks in advance,
David
Usually when someone is presenting a choice between Atomic and SP it is because they are working with an LDS that sells those two brands and "kills" everything else. But let that go and let's look at your questions:

1. World wide service is, in my experience, a sham. I have never seen a properly serviced regulator fail in the midst of a trip thus requiring a rush to a close-by service tech to "save the day." What I have seen is recently serviced regulators, fresh for an LDS fail with disappointing regularity. Even ones that had been "tested out" in a pool before the trip. I will say that I have never seen such a failure given a service tech that I knew and had prior confidence in, which leads me of often recommend Professional Scuba Repair. You ship to the them, they fix it quickly (and correctly) and ship it back to you, often at a fraction of the charge from your LDS (some of whom are know to use PSR and tack on an extra charge).

2. All piston first stages are hard to rinse, some worse than others. This, combined with the fact that a failure to perfectly rinse often leaves salt crystals in the cylinder sleeve that can nick the 0-ring that seals the piston, is what makes me prefer a diaphragm regulator (that'd be a MK-17 if you have to get SP).

3. Yes.

4. No. The problem is that scuba quality air is very, very, dry.
 
I would recommend Atomic Z2 in Yoke for single tank setup. It is inexpansive relatively. Same performance as higher end Atomic. Bi-annual service internval. I said Yoke because I assume you will be using rental tank mostly. I don't like 2nd stage swivel myself, I have mine taken off from my B2 2nd. 1st stage swivel turrent isn't very useful in single tank setup because the turrent will be more or less fixed by the LPI.

Atomic B2 is great, but like I said, I don't like 2nd stage swivel, so I wont pay for it and have it taken off again. Also, I would much rather take a Z2 set + Z2 octo than a B2 with a compact octo tho.

And don't worry about double at this point. When you decide to move to double, you will most likely keep your single setup anyway
 
Hello,

I'm a first time poster and starting to feel really out of my "depth" sorting out which regulator to buy. I think I have narrowed it down to an Atomic B2 or ScubaPro Mk25/A700. My dives will be warm water in Central Texas, the Gulf, and the Caribbean. Hopefully Overseas (SE Asia, South America) at least once a year. I have some questions that would help me narrow down my choice though any advice would be appreciated.

1. I've read on the SB that Scubapro has a worldwide network for service, does that provide an advantage to the vacationing diver who is there only for a week or two? (Quality of Service and quick turn around)

2. I have also read because of some feature on the Atomic rinsing the 2nd stage can be difficult, could you elaborate?

3. To any beach divers or central Texas divers should I be concerned about buying an piston first stage and "gunking" it up?

4. I have trouble with dry mouth and have heard that a metal barrel in the A700 alleviates this, does anyone agree and does the Atomic exhibit similar qualities?

Thanks in advance,
David

1. Don't be too concerned with the world wide service, but, yes, if you are in a foreign country and you happen to need a part, the SP reg will be easier to find parts for. I have been in that situation once on a long trip to Roatan, but it's fairly unlikely that it would happen on a week-or-two trip.

2. The atomics have a "seat saver" which separates the orifice from the seat in the 2nd stage while the reg is not pressurized. I think this is a major flaw, and would not buy an atomic reg for that reason. You can't soak your reg unpressurized, to me that would be a deal killer. However, it wouldn't surprise me if SP was starting the same sort of thing on the A700. It is a nice sales gimmick....

3. Do not worry about a piston 1st stage "gunking" up. Many of the most successful 1st stages in history are piston designs, with literally millions of dives over decades. I routinely see MK 5/10 1st stages over 20 years old that look new. The bit about pistons being hard to rinse is not true. Besides, I think you can get the atomic with an environmental seal kit if you want, although it's totally unnecessary except for very cold water. ANY regulator used in salt water should be soaked-not rinsed- in fresh water after use.

4. It is true that metal 2nd stages, at least the old SP ones, help considerably with dry mouth. But it's not the air barrel; both the atomic and A700 have metal air barrels, as do many barrel poppet (i.e. apeks) 2nd stages. The old SP 109 was a full metal case with a moderate venturi effect, which allowed the expanding air to get somewhat warmed (and added some condensation) so the dry-mouth effect is lessened. I'm not at all sure the A700 would be effective in that way; it has a shorter path for the expanding air, it's smaller, and probably has a very pronounced venturi effect. That's another one of the 'selling point' as a strong venturi effect results in overall lower WOB numbers on a testing machine, but does not translate into a nice natural feeling in use by an actual human. The old D series 2nds somewhat suffered from this; they scored higher on the WOB tests (higher is worse) than the newer smaller venturi-heavy 2nd stages, but anyone who's used the D series knows how pleasant and natural the breathing sensation is.

The point is, higher venturi effect tends to make regulators look like better breathers on sales literature, but the added venturi (often in combination with a smaller case, another "benefit") means faster moving air closer to your mouth, which means colder and dryer air.

As to your regulator dilemma, personally I would not buy either. Assuming you're a new, recreational diver, either one of those is WAY more than you need, or even would be able to distinguish, under water. I'd get a MK11/G250V if I were buying new, but first I'd try to find a good used Mk10/15/20 with a D300/350/400 2nd stage. I think I saw a MK20/D400 on ebay a little while ago for about $120. Dry mouth is a common concern to new divers, and you can mitigate it by making sure you're well hydrated when diving. But if you really want a reg that will feel less dry, get a used SP 109 or balanced/adjustable 2nd stage and have it rebuilt using current parts. I don't know where you are in central tx, but a certified (well, maybe certifiable) regulator guru lives about an hour north of Austin. His username is awap and his wife would be thrilled to see him loan or sell one of his many old metal 2nds. If you're into a bit of bling, there's another guy, also very knowledgeable, in Houston named couv who has been restoring and re-chroming these old metal case 2nds, and when he's finished they look WAY better than the new A700s.

However, it's your money, and if you don't mind dropping $800 or so on a regulator (don't forget you have to get an alternate 2nd stage and a computer or SPG console), then either the top-of-the-line SP or atomic will certainly work well!

Sorry for the long missive....
 
[/COLOR]Whoops, the rinsing thing with Atomics!
If I had to rinse my B2 second stage unpressurized I always wound in the cracking pressure adjustment a few turns first to seal the low pressure seat and then gave it a wash (remember it IS a titanium component system and should not need too much cleaning after every dive).
Then I hung it with the first stage up high and the second below so that any water wouldn't get to the first stage.

I could be wrong, but my understanding is that no matter how you set that adjustment it will not seal the second stage on the Atomic.

I have the ST1, which is functionally the same as the sealed B2. It breathes well especially on deep dives and noticeably better than my old Oceanic Delta 2.

Yes the rinsing is bother. From my shore dives I just dump the tank with BC and reg attached into a plastic box and rinse it pressurized, but otherwise you have to be careful not to get water in.

The other issue is the lack of manual venturi, which can result in free flows when you take the reg out of your mouth.
 
I would recommend Atomic Z2 in Yoke for single tank setup. It is inexpansive relatively. Same performance as higher end Atomic. Bi-annual service internval. I said Yoke because I assume you will be using rental tank mostly. I don't like 2nd stage swivel myself, I have mine taken off from my B2 2nd. 1st stage swivel turrent isn't very useful in single tank setup because the turrent will be more or less fixed by the LPI.

Atomic B2 is great, but like I said, I don't like 2nd stage swivel, so I wont pay for it and have it taken off again. Also, I would much rather take a Z2 set + Z2 octo than a B2 with a compact octo tho.

And don't worry about double at this point. When you decide to move to double, you will most likely keep your single setup anyway

Hi eelnoraa:

There have been a number of post regarding Atomic Aquatics regulator making some unusual noise at depth. Has your B2 been plagued by this issue? How would you compare the Z2 to some of the other regulators that you have used? I also noticed that the Atomic regulators have a very large diameter low pressure hose. It's about as wide in diameter, if not wider, than the hose off my Cousteau/Micra regulator and that has 1/2 inch port. Have you experienced any jaw fatigue or difficulty with the hose trying to pull the regulator out of your moth? I'm am looking for another regulator and choices these days are insane. Was easier buying a regulator 15-20 years ago than it is today.

Thanks,
Claude
 
Thanks for the reply Thal,

I have a local LDS but since I'm moving i hope to start a new relationship. Your advice on worldwide service being a sham is something i suspected but needed confirmation. Anyone who disagrees is welcomed to chime in.

Good diving to you.






---------- Post added April 26th, 2012 at 02:43 AM ----------

Thank you for your reply Halocline,

I really have to say that your reply was extremely well considered an thought out. You have answered my questions and made me reconsider my options. That being said , my friend will remain in NYC while i will be relocating to Austin. She relates top of the line to safety, and considering my lack of expierence I agree. We both have had bad times with rental regulators in the past and fortunately are in a position to buy the top of the line (as long as top is $700 or less) As far as other equipment, we both own BCs, and computers. She actually won the TUSA 950 in a lottery last month from our local LDS, I just purchased the Oceanic OCS.

Thanks for your reply and I'm interested in studying at the feet of your REG "Guru" in hope of Regulator "enlightement" for this diver who is only is just understanding the more I learn, is only finding out what I need to learn.
 
Hi eelnoraa:

There have been a number of post regarding Atomic Aquatics regulator making some unusual noise at depth. Has your B2 been plagued by this issue? How would you compare the Z2 to some of the other regulators that you have used? I also noticed that the Atomic regulators have a very large diameter low pressure hose. It's about as wide in diameter, if not wider, than the hose off my Cousteau/Micra regulator and that has 1/2 inch port. Have you experienced any jaw fatigue or difficulty with the hose trying to pull the regulator out of your moth? I'm am looking for another regulator and choices these days are insane. Was easier buying a regulator 15-20 years ago than it is today.

Thanks,
Claude

As far as I know, noise is coming from Atomic's 1st stage, not 2nd stage. Mine has been quiet. I kind of think the noise issue is mainly due to mis-adjustment. Here in San Jose area, we have one of the best and most knowledgeable regulator tech. I am sure if you take your Atomic to him, he can fix it for you. Let me know if you want to know who he is.

As for Atomic has larger diameer LP hose, this is not true. My guess is that you are refering to the LP hose for SS1. Lots of Atomic users in our area also use SS1. That hose is slightly thicker, but regular Atomic 2nd stage uses regular LP hose. I swapped out my OEM B2 LP hose (swivel) to a 7' long hose, never had draw fatigue.
 
I found the A700 to actually have LESS of a "venturi effect". Case VIVA actually seemed less when compared to the older G250's & D-Series regs. I have compared them side by side. The A700 is however a very well made & smooth breathing regulator. The manner in which it controls the strength of the VIVA effect is different than on the G series regs and in many ways superior to the old flow vane. Fit & finish of the A700 is absolutely top notch & though inhalation effort can be set under 1.0 it is best at 1.0 -1.2 in my experience. Sure the D series Regs could easily be set to .5 or .6. But go back further and you will find that Pilot (even converted) & the Air-1 could be set for a stable .2 or .3 in of water. The Scubapro mouthpiece actually impedes the flow of air inhaled & exhaled. The mouthpiece orifice is larger on the A700 and it's VIVA effect is based on this geometry. Why Scubapro placed a narrowing mouthpiece on this regulator is a bit of a mystery to me. The mouthpiece impedes the flow enough to prevent any sustained vacuum assisted freeflow in the "max" position and WOB suffers from this. I am sure when the reg was tested it did not wear a mouthpiece or certainly not the one it presently ships with.
 

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