M1, B1 or SP25AF/S600

[abedirov]

Please HELP!!! I cannot make up my mind.

I know that both atomic and SP are great breathers. But I have seen several posts that if I were to buy again, I would get an atomic one, so I am currently inclined towards M1 or B1.

Are there any differences between these regulators apart from price?

I have noticed that M1 is havier than B1 or Z1. Is it a problem? Is it havier than SP?

Is it better to get an octopus of the same brand or can I mix and match?

I would appreciate any input.

 

[PnL]

The B1 has Ti in the second stage which makes it a lighter than the S600/M1/Z1 second stage. Both breath extremely well IMO. I have a B1 w/ Z1 backup and my wife has the MK25/S600 w/ R380 backup and both setups breath very well. I've heard of freeze-up problems with the MK25/S600 but its never been a problem and not a concern for the diving that we do. I've never tried the M1 so I can't comment, but its heavier because it uses monel (Z1=brass) instead of the Ti in the B1/T1 series. I think the weight issue becomes transparent underwater. I think the Atomics and SP are great regulators that you will be happy with. See if you can try them and judge them yourself.

As far as mixing brands for your backup, my understanding is that this is not desirable since different brands have different IP's and are, therefore, tuned differently depending on the IP and 1st stage.

 

[DA Aquamaster]

PnL once bubbled...
As far as mixing brands for your backup, my understanding is that this is not desirable since different brands have different IP's and are, therefore, tuned differently depending on the IP and 1st stage.

There is normally just as much variation within brands as between them. SP for example allows and IP of 125 to 140 on most of it's first stages. Most companies have similar range and this hasa lot to do with how IP is adjusted in various designs. In many cases it is not what you would call a precision adjustment.

This variation in IP is taken care of by adjusting the second stage. In a simple downstream design this is accomplished by adjusting the seating depth of the orifice in the second stage to eliminate any freeflow and achieve the desired cracking effort The cracking effort is often set a little harder in an octo to prevent unintentional air loss and also to reduce the need for the octo to be adjusted. If the manufacturer sets there octos on a reg with an IP of 145, it will perform without freeflowing on any first stage with an IP less than 145. However if your first stage has an IP on the low side (120 or so) an octo set up on a reg with a 145 IP will not be as easy breathing as it would otherwise.

 

[Genesis]

I recently had the opportunity to dive a B1.

It does breathe beautifully. Its every bit the reg that my S600/Mk25 is.

However, it has one very serious problem for me - it tends to "wobble" in a current (or when you swim forward at speed!) in my mouth. It feels like the slipstream is "grabbing" one side of the reg then the other in quick succession, leading to a "wobble" that is very uncomfortable.

This is likely some kind of interaction with the cover plate design on the second with the shape of my face, but I couldn't own one of these regs. I dealt for the time of the dive, but I'd never buy one on my own after experiencing this.

I've never had this happen with any other reg - and I've dove lots of them from various manufacturers....

 

[PnL]

Genesis - I wonder if this was more due to the mouthpiece than the face plate? I've never had this problem w/ my B1. I have a Seacure mouthpiece (which I love) currently but didn't have this problem with the Atomic's mouthpiece (older style, not the "two-piece" silicone ones). How much current are we talking about?

DA - Good points. The only thing is that the R380 (non-octo) doesn't have any external adjustments (besides the predive) so it would have to be done by a shop, unless you have the knowledge/experience to maintain your own regulators. Having said that, the R380 doesn't have a free-flow problem as long as its kept in predive mode. The Z1 (non-octo) has adjustors so its easy to back off on the cracking pressure.

 

[Genesis]

Genesis - I wonder if this was more due to the mouthpiece than the face plate? I've never had this problem w/ my B1. I have a Seacure mouthpiece (which I love) currently but didn't have this problem with the Atomic's mouthpiece (older style, not the "two-piece" silicone ones). How much current are we talking about?

These were bone-stock regs. Disney's "Living Seas" is using them this year, and that's where I dove one.....

Needless to say, there's no current in a fishtank! (even though its a HUGE fishtank!)

 

[abedirov]

Thank you for all the responses.

Live is getting harder as atomic has replaced B1 with B2 which uses M1 design, but it is lighter.

Has anyone experienced M1? Can you share you experience?

Many thanks!

 

[PnL]

I haven't read up on the B2 but my initial understanding (correct me if I'm wrong) was that its the same as the B1 but with the new swivel adapter, the wider exhaust tee and different colors. I believe its still made with Ti parts in the second stage which is why its light that than the monel used in the M1. The swivel adapater and wider exhaust tee are available as 'upgrades' to the B1 if you are so inclined.