ScubaPro MK17/S600 vs. AquaLung Titan LX Supreme

[aaron9876]

I've pretty much decided to buy one of these two regs, and would like to know if there's any big differences I should pay attention to. The manufacturer descriptions and reviews (including those here) point to them being almost the same (except for the additional adjustment knob on the S600). I have these questions:

1) Is that adjustment knob on the S600 actually useful?
2) Which one is better in cold water? (I've heard of both used in ice diving with no problems)
3) What makes the Aqualung about $100 cheaper?
4) Is one cheaper to get serviced? (I've heard of the Titan going for years without service and still working fine, but that voids the free parts program I think?)
5) Which is made of better materials?
6) Which is more affected by depth? (I've heard of the Titan LX going to 150+ ft with no problem; haven't heard anything about MK17 at depth)
7) Is the Legend better than the Titan to the extent to warrant the ~$200 price difference?
8) I already have a Seaquest Balance and Aqualung Air Source 3. Should this be a good reason to have an Aqualung regulator also? (I live in San Diego so I can get just about anything serviced very easily here)
9) SD Residents: Has anyone had any good experiences with San Diego dive shops? (such as matching or coming close to LeisurePro prices)

Thanks for the help

 

[DA Aquamaster]

I think the adjustment knob on the second stage is worth the money for a wide variety of reasons - adaptability, ease of adjustment, improved reliability, etc.

The Titan second stage is basically an updated Conshelf design that was in turn an update of the Royal Mistal double hose design, which was a balanced version of the Aquamaster double hose reg. So the design has been around for about 50 years which is both a pro and a con. The pro is that it is a proven design. The con is that it is an old design that has been improved upon by newer designs in several areas.

I am not a fan of the "supreme" environmental kit as it is high maintenenece, old tech, unpleasant to service and prone to leakage and failure. It works well, when it works and things get really oily and/or bubbly when it does not.

The Legend is an excellent first stage design and the LX adjustable second stage is also very good. It uses a poppet (shuttle valve) that is a hybrid of the old Scubapro balanced poppet shape but with a new one piece plastic design similar to what Scubapro did with their current S-wing poppet. So it is a good design.

That said, I prefer the Scubapro S-wing poppet as it interferes with the flow a lot less and is overall a much improved design. In short you can buy the original from Scubapro or a knock off of the last generation poppet from Aqualung.

Similarly the Mk 17 is a superb balanced diaphragm design that evolved from the Mk 17 with improvements in seat alignment and the introduction of a fully sealed dry ambient chamber design. It is currently the most reliable first stage you can find for use in extreme cold water (better than a Legend Supreme) and is the first and only diaphragm reg that I felt performed well enough at depth to replace my Mk 20's and Mk 25's.

So if it were me, I'd go with the MK 17, but I would be ok with a Legend if Scubapro suddenly dissappeared.

Regarding the second stage, I'd go with the G250V rather than an S600. The larger diaphragm of the G250V gives it a slight edge in performance over the S600 and more importantly the metal air barrel in the G250V makes it much nicer to breathe off of on dives where dry mouth may otherwise be a factor. In that regard it is far superior to the S600 or the Legend LX second stages.

Personally, I think the smaller S600 made some sense when the only alternative was the slightly larger G250 given that the performance improvement offerred by the larger diaphragm is not noticeable when they are both tuned to factory specs. But now that the G250V is available, the metal air barrel and improved heat transfer in cold water make it a hands down better choice than the S600. The G250V is larger and heavier - but it also displaces more water so divers will not notice any difference in the water - in spite of the "smaller and lighter is better for jaw fatigue" sales hype that gets pushed on divers.

 

[Couv]

Well thought out set of questions and an equally great set of answers.

Addtionally, the adjustment knob allows for the second stage to be tuned for minimum cracking pressure with the ability for the user to detune it if necessary.

 

[Luis H]

I have to agree with Couv, excellent questions and again excellent answers from DA Aqua Master. But, I do have a couple of minor corrections.

One is just a historical probably mistyped by DA. It was the Royal Aqua Master the predecessor to the Conshelf (and balanced successor to the Aqua Master), not the Royal Mistral. The Royal Mistral was an attempt to a balanced single stage with a very different seat design from anything else US Divers ever made.

The other is that I am fairly certain that all the newer Titan use the same dry environmental seal chamber with the pressure transmitting plunger (similar to most other newer sealed diaphragm regulators). Maybe some of the earlier Titans might have used the old oil/ grease filled chamber, but all the ones I have use the new dry chamber. This includes the new Mistral (same as Titan 1st stage) and the newer environmental sealed retrofit kits for my old Conshelfs.

I use Titan and Conshelf first stages because of commonality of parts with my Royal Aqua Master (I do all my own service), their extremely long term reliability, and their performance is more than adequate for anything than I can think of. Also they are much more readily available in the used market at a lower price than Scubapro MK-17.

On the other hand I use Scubapro metal balanced adjustable second stages as my preferred work horse for a single hose second stage. The closest modern equivalent would probably be the G250V that DA is recommending, which sounds like an excellent choice.

 

[DA Aquamaster]

Good catch on the Royal Mistral versus Royal Aquamaster. Probably a freudian thing since I want a Royal Mistral for the collection and have yet to find one.

Good info too on the dry sealed titan ambient chamber.

I am also still a fan of the older all metal "Balanced Adjustable" second stages and one of the things I like about Scubapro is that they still tend to make improvements retrofittable into older models.

 

[dschonbrun]

The Titan 1st stage only has one HP port whereas the Legend has 2... so if you want to have an SPG and a Transmitter, you'll need the Legend. Also, the legend has many more metal parts which will not wear as quickly as the plastic ones on the titan, and they will manage cold far better.

I would agree with earlier comments about the S600... great reg, but the G250V or HP is better for cold water.

You might also look at a XTX100 1st stage and XTX50 2nd stage. This environmentally sealed set has extremely good breathing characteristics and is well known for it's performance in freezing water. It is a very solid combination in a similar pricepoint to what you're discussing.

 

[aaron9876]

Thanks for all the replies; good information that's made me think of a couple more questions:

1) Any opinions on whether annual regulator service (on a sealed first stage) is really necessary? Especially, I've heard of the Titan being able to undergo several years of abuse with no service or loss of performance. Also, I'd think that since the Titan is very popular for rentals it must be able to withstand some abuse. Even if I had to pay for parts every 5 years (for instance), this would probably still be cheaper then having to pay for service annually.
2) As I said originally, I've seen some posts on this board of people using the Titan LX Supreme both pretty deep and for ice diving, and DA Aquamaster also states that the MK17 is good for the same things. What, then, justifies paying at least $100 more for a Legend or an Apeks regulator? (or $200-$300 more than a Titan)
3) I've also read some comments on this board that the over-balanced Legend sometimes feels like it is "forcing air" at you... any experience on this?
4) Is there any other equipment besides gauges and computers that I might want to connect to a high-pressure port?

 

[DA Aquamaster]

Most first stages can theoretically go years without servicing and that capability has if anything only been increased with the use of modern lubricants like christolube and newer o-ring materials. With a first stage when the reg is depressurized, the orifice and seat are not in contact so no engraving occurs during storage as is the case with most second stages. So if the seat does not develop an excessive seating groove, the lubricants do not dry out and the o-rings are still serviceable, nothing will really change in the first stage even if it sits on the shelf for a decade.

Theory is one thing however while the reality is often entirely different.

Practically speaking there are two other things to consider. Parts that move wear, the o-rings that experience parts movement can be abraded and in particular the seats will wear as the hours of actual use increase. So the more dives and dive time you have on the reg the more in need of service it probably is.

The other item to consider is contamination of the reg. Fully sealed designs do keep water, salt and silt out of the ambient chamber and protect the internal parts there from the increased wear that can occur as lubricants are washed away and as salt and silt accumulate. But that has no real impact on the internal parts of the regulator.

Wear on the seat is going to be the same whether the first stage is sealed or not and factors that may increase seat wear have more to do with things like how clean the gas is that is put through the reg, how may operating cycles it experiences and whether there has been any water intrusion and in particular salt water that can promote very rapid corrosion of internal parts and surfaces. Water may come from the rinse tank through a less than perfectly sealed dust cap, from a small amount of water present in the valve when the reg is connected or from the tank, where it was probably blown from the valve into the tank during a fill.

So in short, a first stage may last 10 years between services for a diver who dives infrequently and stores it under ideal conditions, or it may last only one tropical trip for a diver who forgets the dust cap when rinsing it. In regular service with normal care, 50 hours or 100 dives is probably enough use to justify a service to ensure it keeps working properly.

I have had a few diving seasons where, having redundant doubles, I used one of my regs to the point of failure to see when that would occur. IP creep developed pretty consistently around 120-130 dives with run times on the reg that probably averaged 40-45 minutes per dive. So in this really limited case study (using a Mk 25), 150 hours was about the max before a high pressure seat leak developed and 100 hours of use still gives a prudent 50% safety margin.

Since you can never be 100% sure of things like water in the tank or a slightly leaky dust cap, an annual service is in most cases a good idea and a good time interval for a thorough dissasembly, cleaning and inspection.

------------

With regard to price, top of the line regs tend to have premium price tags regardless of actual performance advantages or actual production costs. Companies charge more to reinforce the impression that it is "better", and in an odd sort of circular logic get away with it because people will pay more because the company says it is better and charges more for it (The customer reasons that it must actually be better because they charge more for it.)

The bad news is that companies often over charge for top of the line regs like but the good news is that in comparision some of the middle of the road regs offer more than enough to even excellent performance and capability at a much lower price and are comparatively a much better value.

 

[halocline]

2) As I said originally, I've seen some posts on this board of people using the Titan LX Supreme both pretty deep and for ice diving, and DA Aquamaster also states that the MK17 is good for the same things. What, then, justifies paying at least $100 more for a Legend or an Apeks regulator? (or $200-$300 more than a Titan)
3) I've also read some comments on this board that the over-balanced Legend sometimes feels like it is "forcing air" at you... any experience on this?
4) Is there any other equipment besides gauges and computers that I might want to connect to a high-pressure port?

2) To be perfectly honest, I think that many divers purchase "top of the line" regs out of hype, maybe a little fear, and some narcissism. Not always, of course, but dive shops and gear manufacturers love those people that simply "have to have the best". For recreational diving there is almost no practical difference between any decent-performing reg. The titan will work great.
3) Forget about the "overbalancing" bit. It's hype. In fact, balancing is highly over-rated as a selling feature for regs. Who would possibly want "unbalanced" when they could have "balanced" even if they have no idea what that means?
4) No, but some people like a SPG and a wireless computer transmitter, hence the need for two ports. On regs with a turret on a right angle, there are also some advantages with having two hp ports, as it give you more flexibility in mounting the reg on the tank.

 

[Jimmer]

The bad news is that companies often over charge for top of the line regs like but the good news is that in comparision some of the middle of the road regs offer more than enough to even excellent performance and capability at a much lower price and are comparatively a much better value.

I agree with this. The nice thing tho, is that sometimes if you're lucky, you can land a really good deal on the "top of the line" regs, perhaps because they aren't selling as fast as the lower priced models or perhaps because the margins are padded a little thicker on the higher priced stuff. It worked out in my favour, I had been planning to buy more Zeagle DSV's for doubles and stages, until my LDS informed me that the Canadian distributor for Zeagle was having a pre Dema sale, and I landed a pair of Flathead VI's for the price of one. If I recall, the DSV discount wasn't the same % reduction as the Flatheads.