Your favourite second stage and *why?

[BoltSnap]

1) Atomic B2 - breathes great!

You're WRONG!

It breathes AWESOME!

(ALL ATOMIC seconds breath the same actually, awesome)

 

[Nick_Radov]

It doesn't matter. Any high-end second stage from a reputable brand like Scubapro / Apeks / Atomic / Halcyon will work fine for everything from shallow reef dives through deep tech dives unless you have some really specialized requirements. Take your pick. They all breathe well as long as they're properly maintained, and you keep the gas density low (no deep air).

What actually matters is local availability of parts and service. And perhaps what your buddies are using so that you can borrow O-rings from them when yours blows out on the dive boat.

 

[lowwall]

Mares Proton Metal. Ok, my only seconds have been Protons, both plastic and metal. But I've never had a problem and they certainly work better than any rental reg I've tried.

 

[Angelo Farina]

For me it is SP 109-126-156-MKX-BA (converted with S-wing poppet, curvy-feet lever).
The latest BA with CE mark and larger exaust valve would be the top, but I did not manage yet to get one.
I tested some plastic second stages, I did like the G250V and G260, but I do not like their excessive venturi effect.

 

[Kupu]

As per title, to those who have a problem and feel the need to keep trying different second stages...

For many years I had just a few second stages which worked just fine and life was simple.
Later I started down the DIY path and fell into the rabbit hole of looking for my "perfect" second stage. Buckets of assorted second stages accumulated, common and obscure. The fun is in discovering the differences that give each its own flavor and character.

My overall top 5 for local fun diving, I tried but can't get the list down to 3 right now. And there are at least 10 more that I feel bad not to mention here...

• SP G260 - Very good breathing performance. Durable and easy to maintain, seat saver feature. This is the second stage I would pick if forced at gunpoint to keep only one.
• SP Air1 - The absolute easiest breathing 2nd I have, better than my best non converted Pilot. Cracking at .2" with modified LP seat, the huge exhaust valve gives effortless exhalation. Servicing was a bit of a learning curve, but quite easy after figuring out the tricks. Not the most practical set up, but I love using it and usually pick it over G260 for local dives.
• Poseidon Cyklon - Very good breathing performance. I have both metal and plastic versions, personal preference for the metal. Durable, the design does make servicing slightly more complicated relative to something like G260. Bonus points for the metal chrome look.
• SP Balanced Adjustable CE - Very good breathing performance, on par with G250s since this version has modern 33mm exhaust valve. Easy to service, although the G260 does have certain advantages in that department. Key style seat saver. Some of my best dives and diving years were with a Balanced Adjustable. So performance plus sentimental attachment means this would be my second gunpoint pick after G260. Bonus points for the metal chrome look.
• Hollis 500se - Excellent breathing performance, second only to my Air1. I switched to this after loving the breathing performance of the Oceanic Omega II, but not loving the sometimes wet breathing on the Omega. The Hollis 500se exhaust cover is prone to splitting if removed for serving, and the retainer cover is made of material that disintegrates with age. As these parts are getting hard to find, the 500se is not the most practical, but still very enjoyable to dive.

 

[undrwater]

Any brand / manufacturer that supports and encourages self service.

 

[Kupu]

Boo to those that are not playing with us by listing favorites. This is not a list of practical answers for second stage choices.

A few of the seconds mentioned so far are not very practical at all, but great fun to dive none the less.
I see this thread as a hobbyist list of favorites, or for those that enjoy exploring the differences in second stage design. Those who have the problem understand the point.

In a completely fun way, second stage choices matter to me. My wife has no interest at all in using most of my collection, she prefers a good ole modern SP second stage. Her S600 and C370 are great performers, there is no need for anything better. But she agrees my modified Air1 beats them both for simply effortless breathing.

 

[Eric Sedletzky]

The second stage is what determines ease of breathing/ breathing characteristics with any set.
The first stage really has little to do with it unless there is something really outside the spec range, or the 1st is a very old diaphragm model that really can’t keep up with demand, let’s say two divers huffing away on one reg deep in an air share. But any nicely tuned high performance second stage makes up for a lot of inadequacies of some pretty crappy first stages.
That’s why I laugh when people start comparing which first stage breathes better than this one or that other one, etc. 99.9999% of your breathing ease will be in the second stage.
That’s why this is a good thread.

 

[Shabaday]

Ok I wanna play
1) Tie between my G260 and my XTX200 second stage
2) Atomic ST1/M1
2.5) D420
3) Waiting for my C370!! so this ranking might change
4) Cyklon 300 and Odin
5) In all fairness I have a Deep6 Signature that breathes every bit as good as my G260/XTX200
6) S600/620ti

THE COMMONALITY IS RSINGLER tuned my D420/ST1/XTX200

 

[BoltSnap]

Halcyon

That's Scubapro