Scubapro A700 Vs. S600

[flyboy107@gmail.com]

So, I was planning on either pairing a S600 or a A700 with a mk25. I live in the midwest and do about 25% of my diving in cold water, such as ice dives. If anyone has these regs, let me know what you like/dislike about them. Also I personally like the look of each, so looks are not the issue

 

[DA Aquamaster]

The S600 has for most of its history had a plastic air barrel although you can find metal air barrels in the very early S600s as well as the current new production S600s. The plastic air barreled version does not do all that well in cold water due to poor heat transfer. The area around the seat and orifice in any second stage is cooled by the expanding gas flowing past it (the gas has to acquire heat in order to expand) and the temp falls far below freezing. If water droplets then come in contact with the chilled parts ice will form.

A metal air barrel helps transfer heat from the water to the interior of the second stage. A metal second stage case is even more efficient in that regard.

The S600 and A700 are generally similar in terms of how the balanced poppet works, but the A700 has the air barrel located more directly in front of the mouthpiece and uses a better flow vane arrangment.

Both are good regs but the A700 is better.

However I am not sure it is worth the extra cash, especially compared to a G250V. The metal air barreled original G250 and the current G250V (but not the G250HP) has long been a gold standard in very demanding technical diving applications, and I still think it is on balance the best second stage Scubapro makes.

If you are doing cd water dives and ice dives the Mk 25 is a poor choice. Below about 45 degrees you'll need perfect cd water technique to prevent a freeze flow, while the Mk 17 is basically bullet proof. In terms of performance and air flow, you'll never tell the difference between the two.

 

[flyboy107@gmail.com]

I know this is going to sound dumb, but is there any worry with barracudas in the ocean or any other predators? i do a good amount of diving in the Caribbean too. also, is the black teck worth the upgrade?

 

[DA Aquamaster]

No worries with barracuda, and no, I don't think the black tech finish is worth the extra money.

 

[flyboy107@gmail.com]

true, plus the black teck doesnt come in a mk17 in the US for whatever reason.

 

[DA Aquamaster]

Scubapro's marketing strategy is to create beginner, intermediate, advanced and,apparently, premium packages. With that type of model you force people to upgrade a level to get certain features. For example you'll note the adjustable flow vane disappeared from the R380/390 forcing customers to move to a balanced reg to get that feature. That trend has been reversed with the C200 and C300 but I think that has a lot to do with unbalanced regs being preferred by many European divers.

Scubapro does the same thing with regulator packages. You can't get a balanced second stage on a MK2 even though the concept has a great deal of merit.

I'm ok with that as you can order what ever you want separately but Scubapro is missing some potential US sales when they treat the Mk 25 as their premium regulator when quite frankly the Mk 17 has a lot more to offer in terms of overall performance.

What really annoys me is when they degrade the performance of a regulator to meet their package / level strategy goals. For example the Mk 11 has less flow rate than the Mk 17 - but only because Scubapro limits the working range of the valve by using a thicker diaphragm and one less washer in what is otherwise an identical first stage body. In the past Scubapro would have sought to maximize the performance of every reg in their line and not intentionally limit performance.

 

[ajduplessis]

The MK25/A700/S600 is a great reg set and performs very well. However it is not the right equipment for ice diving, as stated before me they will work great down to 45f. The MK17/A700 was tested for ice diving, but I struggle to find more detail around this. The MK17/G250 will perform well during ice dive.

I also agree that the MK17 in under rated and has more to offer that the MK25. I own the MK25 and love them, but the coldest waters here are in the 45f range.

 

[CuNanoTube]

I use my MK.17 / A700 in very cold water. I have never free-flowed with it save one ice dive where it was left on the ice for 45 minutes before the dive. Today in Tobyermory the temp just below the thermocline was 2C (36F?) I had no problems.
I do know a guy with a mk.25, and he has had free-flow issues. The A700 is great (plus the metal body helps absorb heat), but the G250V will work as well.

 

[Chill Diver]

+1 to Hashime's post. I purposely bought the Mk17 to go with my A700 because of its cold water performance. The all-metal construction of the A700 makes it a better cold water choice than the s600. That being said, I have seen a lot of people around these parts diving the s600/Mk17 combo and not having any issues.

I think you will be very happy with a Mk17/A700 set. You would be hard pressed to find an easier breathing reg. So far, the coldest I have used mine was air temp -2c / water temp 4c. No free flow issues at all.

 

[50Fathom]

I'm ok with that as you can order what ever you want separately but Scubapro is missing some potential US sales when they treat the Mk 25 as their premium regulator when quite frankly the Mk 17 has a lot more to offer in terms of overall performance.

Do you think that's because SP is basically a "piston company" and has their engineering history and "corporate identity" tied to piston firsts?

I'm a Mk17 fan and prefer it to the Mk25, but you're right, I see the Mk25 pushed HARD over the 17 in many cases. The shop I work in prefers it because "it's more expensive" and they make more money on each one sold, and the company seems to like it because "it flows so much more".

When I took my SP tech training, they kept going on about the Mk25 and its awesome flow rate and how amazing it was. The 17 was described and talked well about, but you could tell they really didn't like diaphragm first stages and in their words, "we only built it because northern European divers demanded a better cold water regulator". They kept saying how it made no sense to open the valve against the airflow and it restricted maximum flow potential and unless you're in the Arctic, or are (and this was said), "a crappy diver with poor cold-water technique", there is no need for the Mk17 and the Mk25 is better.

Granted, I'm new to this whole regulator-tech thing, but it seems to me that a lot of the Mk25 design "features" are in fact band-aids for poor cold-water performance. The finned "T.I.S." body on the reg, the rubber washers that fit over the piston stem, etc. It also seems that the "300 SCFM flow rate" is more of a bragging rights thing than truly needed, since (at least in the diving philosophy I subscribe to), you are getting helium in the mix pretty early, (anything below 100 feet) making for an easier-flowing gas, and obviating the need for insane flow rates to give good WOB.

I personally love the Mk17 and would LOVE to get a set of now-discontinued Mk19s for doubles, even though my Mk17s are doing quite well in that role now. Only thing I don't like is the angle of the HP port, since it seems to push the HP hose fitting right into/at the wing, causing a bend right after the swage, no matter how I route the hose. I wonder if the Mk19 HP port is closer to 90* from the tank valve input, since it seems on the 17 that the LP port positions precluded a 90* location of the HP port.