Most desirable ScubaPro 1st Stage .... ?

[rhwestfall]

I own MK-2+, MK-5, MK-10, MK-10+, MK-15 (I think - it was a gift, and is in a box somewhere) & MK-17..... Each has its use. I have no desire to own a MK-25... For the cold water here, its MK-17, and a MK-2+ on my pony. In the warmer stuff, its the MK-10 & MK-10+ as primaries. Actually, I never had a problem with my MK-10 in the cold (39 degree water), but couldn't turn down a deal on some regs.....


as to routing, swivels in the first stage work quite well for me (YMMV).

 

[beaverdivers]

Both the Scubapro MK25 & MK17 are excellent 1st stages.

We use the MK25 in our training & rental.

 

[Aqua-Andy]

Hey, Scubapro, listen up! I'm a big fan, and not slagging off on you, but you REALLY need to bring back the Mk19, AND let us in North America have it! Mk17 awesomeness with Mk25 hose routing. It would be the only first stage you would need to make.

Brand loyalty is one thing but if they don't want to sell you what you want you just need to vote them out with your wallet. I's not that they don't make the product you want they just choose not to let you purchase it. There are several companies that have diaphragm first stages that have a bottom port for hose routing similar to the MK25.

 

[halocline]

Halocline, the IP is higher at low tank, this is why SP recommends to set the IP at 145psi at low tank and work from there.

A 5-10PSI change in IP over the supply range is not the end of the world, if you're using balanced 2nd stages you'd probably not even notice it. My MK10s drop 7-10PSI depending on the HP o-ring (polyurethane drops less) and with a D series 2nd stage I don't notice anything while diving. One could probably measure the difference in WOB but in real-world terms it's inconsequential.

The MK25 (or MK20 w/composite piston) is pretty amazing in terms of IP stability, drop, and recovery. But I think you primarily notice that on the test bench, not while diving.

 

[axxel57]

A 5-10PSI change in IP over the supply range is not the end of the world, if you're using balanced 2nd stages you'd probably not even notice it. My MK10s drop 7-10PSI depending on the HP o-ring (polyurethane drops less) and with a D series 2nd stage I don't notice anything while diving. One could probably measure the difference in WOB but in real-world terms it's inconsequential.

The MK25 (or MK20 w/composite piston) is pretty amazing in terms of IP stability, drop, and recovery. But I think you primarily notice that on the test bench, not while diving.

A 5 - 10 PSI change, anyway in which direction, is not the end of the world, especially when you are using the D-serie as the second stage.
My expirience is that about 0.3 psi presssure difference translates in 0.1 inch\ water increased cracking effort using a R190\R295 (unbalanced 2nd ).
I just serviced the MK20 - D350 of my girl friend. The IP drop from full tank to 600 psi was 6 psi, the cracking effort increased by 0 (0.6 inch\water).
So I'm not surprised if you don't feel any difference.
My documentations show me that for balanced 2nds you can expect a 0.1 inch\water cracking effort at 6 - 8 psi IP drop or rise. I had one MK17 - D300 with a 9psi IP differnce which did not translate into a cracking effort increase or decrease, but that makes also me wonder if there was a measurement error.
Anyway I think even if it would have make only a 0.1 inch\water difference.
As I see it, a 12psi IP difference with an unbalanced 2nd stage could translate into a 0.4 inch\water increase\decrease of the cracking effort, and for quite sure you can feel it, especially if you are in strenous conditions.
Assuming my documentations are correct, up to which IP difference we should consider a 1st stage as practically balanced, regardless of its technical design?
For me personally, I consider a 1st stage balanced, if the IP difference between a full tank and a near empty tank (600psi) is not more than 8 - 9 psi.
I'm sure others think different of this, but this issue is bothering me for a while.

 

[Islandheart]

Lots of good discussion but Mk-19's are not available, so it's 17's or 25's.... ???

 

[Couv]

Lets see now,
2 MK 10s + 1 MK 5 = 1 MK 25

 

[rhwestfall]

Lets see now,
2 MK 10s + 1 MK 5 = 1 MK 25

Never thought of it that way.... guess I have one then.....

following that logic, with my MK-17 and my MK-2 I have the elusive MK-19 too.......:cool2:

 

[tplyons]

Love my MK25 but also enjoy the MK17. But since the majority of my diving is warm weather, single-tank diving, I'll take the MK25 for the swivel.

When I do cold water diving, I'll swap the MK25 for a borrowed MK17 and am quite happy with the performance but miss the swivel.

Sounds like I need to track down a MK19 for the best of both worlds....

 

[CMAN]

I just purchased a new MK19/G250V got it from a dealer in Germany and shipped here to the U.S.