g260 vs. s600

[rick00001967]

hi all
i got some great info here (and elsewhere) on comparing several 1st stages. so now i am looking at my 2nd stage options.
i was lucky that someone locally dives a pair of mk17's with a g260 and an a700 and he let me try them out in the pool. i loved the a700 but probably will not want to spend the extra $. the g260.....not so much. i found the g260 to be quite big, bulky, and heavy. i am wondering how it compares to the s600.
i have never seen an s600 in person let alone been able to test dive one so i am looking for some opinions here.
thx

 

[LowDrag]

I dive a paiar of S600's and love them. Light weight and easy breathers. Mine are paired with a Mk25. IMO you can't go wrong with S600's.

 

[DA Aquamaster]

The G260 and the S600 use the same poppet and the same valve design, but the G260 uses a larger diaphragm to drive the internal parts. The G260 is essentially a G250 modified with a new case allowing it to be set up with a left or right hand inlet.

Small is fashionable and smaller second stages get sold on the concept that they are smaller and lighter and therefore better.

Just be aware it's BS.

A larger second stage displaces more water and when the case is plastic and the air barrel is metal, the end result of a larger case is a regulator that feels the same, or even lighter in the water. Plus that larger diaphragm provides much more surface area, reducing the inhalation force needed to open the valve. There won't be much difference just after a service when both are tuned to the same cracking effort, but give it a year of hard use, some lost lubrication, a little sand and salt, etc, and you'll be getting better performance from the larger diaphragm second stage.

As noted above G260 is capable of being set up with the inlet fitting on the right or left, where the S600 is not, and in addition the G260's metal adjustment knob and inlet fitting and nut give on it much better heat transfer, making it much more reliable in cold water than the S600.

The only possible downside to a G260 is the larger case takes up a little more room under your chin when used as a bungee backup second stage, but even then it's just not an issue. So don't listen to the sales person and don't be put off by a "larger", "bulkier" second stage.

 

[rick00001967]

good info once again. to be clear.....i tried the g260 myself. i am not claiming any sales people told me this. compared to the a700 i didn't like it. but i have no way to test an s600 to compare to the g260 for myself.
i did find it to be quite large and bulky. i am sure (like anything else) that i would get used to it when using in single tank back mount. but i don't think it would be my first choice when diving double tank side mount.
interesting info about the extra metal on the g260 for use in cold waters. i was under the impression from reading scubapros info that the s600 was all metal as well. perhaps i read too much into that.

• Metal valve housing is able to withstand years of aggressive diving.

---------- Post added December 12th, 2015 at 08:19 PM ----------

good info once again. to be clear.....i tried the g260 myself. i am not claiming any sales people told me this. compared to the a700 i didn't like it. but i have no way to test an s600 to compare to the g260 for myself.
i did find it to be quite large and bulky. i am sure (like anything else) that i would get used to it when using in single tank back mount. but i don't think it would be my first choice when diving double tank side mount.
interesting info about the extra metal on the g260 for use in cold waters. i was under the impression from reading scubapros info that the s600 was all metal as well. perhaps i read too much into that.

• Metal valve housing is able to withstand years of aggressive diving.

so is the s600 body made from plastic and / or composites with only the "air barrel" being metal ??

 

[DA Aquamaster]

good info once again. to be clear.....i tried the g260 myself. i am not claiming any sales people told me this. compared to the a700 i didn't like it. but i have no way to test an s600 to compare to the g260 for myself.
i did find it to be quite large and bulky. i am sure (like anything else) that i would get used to it when using in single tank back mount. but i don't think it would be my first choice when diving double tank side mount.
interesting info about the extra metal on the g260 for use in cold waters. i was under the impression from reading scubapros info that the s600 was all metal as well. perhaps i read too much into that.

• Metal valve housing is able to withstand years of aggressive diving.

---------- Post added December 12th, 2015 at 08:19 PM ----------



so is the s600 body made from plastic and / or composites with only the "air barrel" being metal ??

The S600 started with a metal air barrel - the same one used in the G500 - but then switched to a plastic air barrel, then back to a metal one due to issues with the plastic air barrels cracking at the inlet fitting.

The difference in the S600 and G260 air barrels is in terms of what's on each end of it. In the G260, the metal air barrel has an exposed finned nut on the inlet fitting side while the other end has a finned metal adjustment knob, and those metal fittings convey heat from the water to the air barrel itself. On the S600, there is basically no exposed metal on the inlet fitting side, and the adjustment knob is plastic, so there is essentially no heat transfer from water to air barrel.

The G260 the earlier G250 and the S600 use a composite case. In practice they stand up very well in service unless you do something like drop a tank on it, where you run the risk of cracking it. If you do that, replacing the case will cost you all of $13 and will take your technician about 10 minutes to move all the parts to the new case and retune the second stage. Marci and I have broken two of them in the last 10 years, between two sets of side mount regs, a pair of deco regs, and a number of stage regs, all using G250 second stages. I keep a spare on hand, but it will most likely go unused for another 5 years or so.

 

[rick00001967]

---------- Post added December 13th, 2015 at 09:57 AM ----------

The S600 started with a metal air barrel - the same one used in the G500 - but then switched to a plastic air barrel, then back to a metal one due to issues with the plastic air barrels cracking at the inlet fitting.

The difference in the S600 and G260 air barrels is in terms of what's on each end of it. In the G260, the metal air barrel has an exposed finned nut on the inlet fitting side while the other end has a finned metal adjustment knob, and those metal fittings convey heat from the water to the air barrel itself. On the S600, there is basically no exposed metal on the inlet fitting side, and the adjustment knob is plastic, so there is essentially no heat transfer from water to air barrel.

The G260 the earlier G250 and the S600 use a composite case. In practice they stand up very well in service unless you do something like drop a tank on it, where you run the risk of cracking it. If you do that, replacing the case will cost you all of $13 and will take your technician about 10 minutes to move all the parts to the new case and retune the second stage. Marci and I have broken two of them in the last 10 years, between two sets of side mount regs, a pair of deco regs, and a number of stage regs, all using G250 second stages. I keep a spare on hand, but it will most likely go unused for another 5 years or so.

aquamaster......last question (i hope) at least for awhile haha

i was shown a sub gear SG50. it is supposed to be the same as the mk17 but paired with c350 2nd stage (i think). by the sounds of the description, it would be a perfect cold 1st stage. but what about the 2nd stage ? i don't see any info that convinces me it would be a very good choice for extreme cold. your thoughts ??

 

[DA Aquamaster]

---------- Post added December 13th, 2015 at 09:57 AM ----------



aquamaster......last question (i hope) at least for awhile haha

i was shown a sub gear SG50. it is supposed to be the same as the mk17 but paired with c350 2nd stage (i think). by the sounds of the description, it would be a perfect cold 1st stage. but what about the 2nd stage ? i don't see any info that convinces me it would be a very good choice for extreme cold. your thoughts ??

I was an early adopter with the C300, and the C350 reflects the improvements they made in the design. The early C200 (non adjustable) and C300 (adjustable) second stages used close guides on the poppet that mated with close fitting grooves in the air barrel.

However, if you got sand or silt in the grooves, it was possible for the poppet to stick - and that was a potential problem in the side mount dives I was doing with it. The quick fix was to use rounded guides on the poppet that allowed more room for sand or silt in the slots in the air barrel. The longer term fix was to go with an oval shaped poppet assembly using the shape to keep it aligned with no need for a groove. That is in essence what you have with the C350.

Other than the sand and silt issues, which Scuabpro resolved after hearing about the problem, I liked the C300 and C300 second stages are what we're using on our bailout bottles in CCR, due to the compact size, simple design and excellent performance.

The C300 uses a smooth, curved rod as a lever, like the X650, and it's a design that provides few opportunities for ice to form and obstruct the lever or the poppet assembly, which is a plus in cold water. However, the air barrel is plastic, and the C300 would not be my first choice in sub 40 degree water, and I'd still take the G250 or G260 in those conditions.

As for the SG50, it is a clone of the Mk 17 with a C300 or C350 second stage - I'd have to look inside to see what poppet and air barrel they are using - and it's a great regulator for the money.

 

[JulesSCUBAPRO]

The information you seek can be found on page 9 in the regulator owner's manual located here: SCUBAPRO - Product Support

 

[zf2nt]

This is a very interesting discussion with some well-formed perspectives being expressed. Now here are mine:

(1) I used to dive a MK25/A700 while I owned a dive shop and serviced all of my customers' regulators. One reg that always surprised me was the G250V. No matter how I looked at it, I just liked the way the G250V breathed better than the way the A700 breathed. When I sold the shop, I had a G250V that was going along with the inventory. After I thought about it a while I decided to sell that G250V to myself and that's what I have been using ever since. I take my A700 along as a backup whenever I travel, though. And that's the only use it ever gets! I really like the G250V better.

(2) I have a C200 as my AAS. One day when going out from shore on a sandy beach I got knocked down by a huge wave, and by the time I got back on my feet I had sand all over me. Never mind....I went ahead with the dive. While I was down, I noticed a slow stream of bubbles coming out of the C200. I hit the purge button, hoping that would clear it. Big mistake! It got stuck in the full free-flow position and nothing I could do would stop it. It completely drained my tank. Later when I got a chance to tear it apart I saw how sand had got in the air barrel and was wedged between the poppet and the barrel. That's what had the poppet held in the open position and indeed there was nothing that could be done about it while I was diving. I think that poppet is a very poor design. It would not have been that difficult to make it more like a S600 poppet so that the sand wouldn't jam it so easily. I still use that C200, but I'm always mindful of how sand can impact it.