What is the difference between SP G250V and S600?

[Merrimorte]

Yeah I love my g250v! I have been in water in 30 some degree water and didnt have a freeze up problem. As far as weight concerning jaw fatigue. Nope not experiencing it. :>

 

[pescador775]

Melnerah, the show and tell was interesting in technical content and with commendable candor. It is rare that we get the other side of the story, more often just cheer leading or bashing. Thanks again.

 

[Richard Paul Halstead]

I personally like the r156 or the converted r109ba then comes in the older g250. They are also very easy to work on.

 

[DA Aquamaster]

Hi eelpout, i have both s600 and g250 v, lso i have 295, 395, s555, s550, g250 hp, 380, ....,and i have tested all of them. i agree with you that it is better for cold water, but don't tell me that the spring adjustment inside isn't needed; i'll explain you all why. In 3 or 4 years i'll prefer to adjust the spring tension inside rather than changig spring because of using, moreover all adjustent mechanism that can be added to any second sttage is wellcome, because it helps every mechanic to adjust the breathing effort at minimum.

jaja, yeahhh, it is now ok for cold water, but also s600 can be used in cold water, s600 breathes much much much better than 250 v, costs only 40 euros more, it's much more improved inside than g 250 v, and s600 will not have to be cleaned of oxide each year because of using with acid, because it is plastic.

i think, they could have made a better regulator, despite of this i have one g250 v, and i think that they design he best "regulators" in the world, but not this time.

Moreover, I could say that scubapro g250 v is identical to this apeks n the link of bellow:

FORO DE BUCEO DEPORTIVO :: Ver tema - interioridades de nuestros regus. Apeks TX100

Best regards

You are completely correct in that imitation is the sincerest form of flattery - but you have it backwards.

Consider the two pictures below. The first (the blue poppet with the chrome plated brass stem) is the original Scubapro balanced poppet as used in the R156 Balanced Adjustable and a few years later the original G250. The R156 was an early 1980's design and the G250 was introduced in the mid 1980's. At that time, Aqualung had plastic variations on the Conshelf second stage design - a basic unbalanced downstream poppet design - and Apkes had not even been thought of yet.

The second picture (the white poppet) is the current S-wing poppet that Scubapro developed about 10 years ago. It is a direct replacement for the earlier poppet.

I noted when I dissasembled my first Legend LX second stage, that Aqualung had copied the shape of the original scubapro balanced poppet, but made it all out of plastic just like the new Scubapro S-wing poppet. The only difference was that they used black plastic rather than blue and they call it a "shuttle valve" rather than a poppet.

As your Apeks pictures illustrate, the TX100 is essentially a G250 with minor changes in the balance chamber and adjustment knob.

In fact, if Scubapro went out of business tomorrow, I'd probably buy one just because it is a pretty good copy of the G250. But it is a copy. So before you start bashing Scubapro's design work, you need to understand that Aqualung/Apeks did nothing more than copy a 20 plus year old Scubapro design.

The G250HP has more parts and is more complicated in the balance chamber/adjustment knob area, but that does not make it better, just more complicated. If you actually take one apart, you quickly realize that there is nothing there in terms of additional adjustment. It is just a threaded stem containing the balance chamber that screws in the end of the plastic air barrel and has splines to engage the plastic adjustment knob. It replaced the metal adjustment knob with one o-ring found on the G250 with 3 plastic parts and three o-rings.

Also, you imply that the lack of adjustment is going to reduce spring life. That argument is false. I work on 20 year old G250's on a weekly basis and I have yet to ever find one that needed a new spring. Not one. Ever. As long as a spring does not exceed its working range, they do not wear out in any meaningful sense of the word.

Scubapro is guilty of killing off one of the best second stage designs ever made (and Aqualung Apeks would agree on the quality of the design since they copied it) but at least they rectified the error by bringing it back. I am greateful for that as I was one of the cold water diving midwesterners who was not happy with regs that did well in testing in Costa Rica and other great test sites for SP tech reps. Several times I offerred to test new regs in 35 degree water at 150' but they never took me up on it. Sadly it took other companies cashing in on Scuabpros's tactical error in discontinuing the G250 to convince them to put it back into production. At one point, used G250's in excellent conditon were bringing more on e-bay than brand new grey market G250HP's - that said a lot about the G250's value to the tech community.

In my opinion, the G250V is an evolutionary improvement in that the air barrel is slightly longer and accommodated a larger and longer retention nut that does an even better job of transferring heat.

The S600 does not breathe better than the G250V. The S600 has a smaller diaphragm that provides less mechanical effort to operate EXACTLY the same lever and S-wing poppet to act against the smae basic orifice design. The difference here is that the G250V, like the original G250, uses a harder and sharper metal orifice compared to the S600's plastic orifice.

Also, you only need one spring adjustment on a second stage, not two. The spring compression is already adjusted in the G250/G250V by means of varying seating depth of the orifice. This also adjusts the lever height, but as long as you have adequate quality control to remain within the design parameters for the spring, airbarrel and lever, you will get proper lever height with proper spring tension. So I'd argue if you need a second spring compression adjustment, it is because your design and/or your quality control is flawed.

The S600 is notorious for freeze flowing in very cold water (below 40 degrees F). The plastic air barrel, knob, inlet fitting and in some model years, retaining nut, do not transfer heat to the interior of the reg. Consequently the air barrel and poppet can be cooled well below freezing and any water that contacts them will freeze. If an ice partical blocks the poppet or prevents it from seating against the orifice, a freeflow will result.

In contrast the heat transfer traits of the metal parts of the G250 and G250V mean the internal parts exposed to adibatic cooling remain above freezing.

Finally, I have no idea how many regs you clean or service per year, but I see salt and silt deposits on plastic air barrels all the time - just as frequently as on metal air barrels. Consequently, they need cleaning in a ultrasound bath just as much as chrome plated brass air barrels.

 

[H20lover]

That was the most comprehensive explanation of the two regs I have yet to read. I commend all of you for your attempts to explain a rather simple and benign comparison only to literally backup the claims of one vs. another.

 

[melnerah]

I don't agree with you about cleaning metal or plastic. i don't need ultrasounds to clean plastic air barrels, it's enough with water, but i need acid or ultrasound in case of metal, then it is easier with plastic ones.

Moreover, if you have a spring adjustement inside, you can have at minimum the external one and increase the breathing effort with much more accuracy. Of course, i don't need inside any adjustement to make it runs great, for example, r190, r295,395,... don't use external or internal adjustement, with turning the nut or the orifice you can get it.

In conclusion, is it needed to have a second ajustement inside?, no, of course, but it is much better, and it is hepfull for people that don't know to open the second stage to adjust the cracking effort. If it wouldn't be necessary it, s600 and x650, or other regulaotr of other trademarks wouldn't have it.

Despite of this, if i'm wrong, explain me why it isn't necessary a second adjustement inside, or why the best regulators have it, i have learnt by my own, reading and dismounting second and frst stages, everyhing i can learn is really wellcome, of course if it comes from someone whose job is diving equipment maintenance. ( sorry about my english, i'm spanish)

You have a private message

 

[vshearer]

DA, I just want to know when the book is coming out.

 

[pescador775]

Melnerah, the G250v with its metal orifice can theoretically be adjusted to produce higher intial performance, probably for about a week before something changes, LOL. I was almost certain that was what was behind the new claims concerning the G250v; and DA, with his excellent post, confirmed. IMO, the trade offs are complexity and long term service interval (G250HP) versus simplicity, touchiness and easy turn around(G250v) on a one year interval. Also, as above, the new, vintage regulator has good cold water character. Apparently, the "high performance" of the plastic regulator is claimed because the pneumatic spring ("balance" mechanism) and mechanical spring are adjustable whereas in the G250v only the mechanical spring is adjustable. That appears to be implied by claims in the literature as regards the 250HP. I am not sure if that can be supported by facts. Both have an orifice adjustment and the functions were described by DA. On balance, the simpler, vintage regulator is probably easier to live with but I wonder about the service history of regulators which require sharpened orifices and soft seat materials to get the numbers and the advertising claim that goes with it. For production reasons, they may share the same type of seat but however it is done there is no free lunch. On the other hand, if the G250v uses Scubapro's pneumatic relief valve(anti-set) which removes closing force from the poppet when depressurized then my concerns about the 250v would probably go away. I have not looked at the actual drawings but your "exploded" parts displays were an eye opener.

 

[DA Aquamaster]

DA, I just want to know when the book is coming out.

I'd need a really good editor to keep me motivated, on track and to fix all my dyslexic spelling errors.

 

[H20lover]

That's ok about your english... I had a hard time reading spanish on the forobruceo.org forum. I understand you very well. Mui Bueno!! Gracias...