SCUBA Pro G250 vs. S600

[White Knight]

Other than the visual look, is there a difference between the SCUBA Pro G250 second stage and the SCUBA Pro S600 second stage? I have dove SCUBA Pro my whole life (25 years of diving) but my most recent SCUBA Pro reg I purchased (the S600) didn't perform like earlier regulators? I even had it rebuilt. It didn't breath as easy and sometimes "stuck" after being stored just a few days. I was wondering if it lacks in quality as compared to past regulator models and/or does the G250 still possess the tradition of SCUBA Pro excellence? If so, I'll buy one now. Thanks.....

 

[DA Aquamaster]

Small regs are cool - just like small cell phones. Just ask the advertising weenies and they will tell you how great small and lightweight is and ow it reduces jaw fatigue, etc. It is all crap but it sells regs to people who don't know any better.

"Lighter" means more plastic, which means more dry mouth, duller plastic orifices, less heat transfer and more potential for freeze flows - all bad things in a regulator.

"Smaller" also means a smaller diaphragm with less mechanical advantage to drive the internal parts, which means greater inhalation effort - whihc frankly means a lot more than total work of breathing if the breathign scores are generated by a positive pressure cycle that feels anything but natural.

So in effect, you are exactly right - the S600 is half the regulator the original G250 was in terms of perfromance and quality of beathing. It devolved in stages over time. The G250 got "smaller" and became the G500 with a smaller diaphragm working harder to drive the same internal valve components. The G500 in turn lost it's metal air barrel and metal orifice to become the "lighter" S600. Meanwhile the G250 also spawed the still large but all plastic G250HP, which is better than the S600, but still not the same as the original G250.

The good news is that SP finally got a clue when original 20 year old G250s in excellent condition were selling for nearly as much as brand new S600s and then reintroduced the G250 as the cosmetically altered and slightly modernized G250V complete with metal air barrel and metal orifice.

So in effect, Scubapro has finally started moving back in the right direction and the G250V is a superb reg with the same fine peformance as the original G250.

 

[Bluey]

I wonder how well your reg was tuned. While the g250 may breath a little better I think the S600 breaths very well when tuned properly.
Once I learned to tune my reg myself, I was able to tune it to breath MUCH better than my local dive shop and with a much lower cracking pressure than the factory spec (with absolutely no problem with free flows). I have mine tuned to around .7" cracking pressure.

Bluey

 

[White Knight]

And where does one learn to rebuild/tune their SB regulator? I have been told that SCUBA Pro will not allow me (a simple diver) to receive training? In the old days, the SB regs came perfectly tuned out of the box? I then took it to a SCUBA Pro dive shop to have it serviced, but still it didn't breath as well as my past SB regs. Kind of defeats the purpose of only buying SB gear from authorized Local Dive Shops and paying the premium if I have to rebuild it? Perhaps the answer is to buy it on Leasure Pro and then do a personal rebuild? Anyway, I truly thank you for the advice and apparently you have found a work around for the problem I face.

 

[Bluey]

You can download the repair guide for the S600 from http://www.frogkick.dk/manuals/scubapro/Manuals/2. Stage/S600-S550 Repair Guide.pdf

Page 17 deals with adjusting the reg.
If your reg is relatively new it is probably the revision A, and the cracking pressure is adjusted with the 3mm screw driver as shown at the top of the page.

You just need to remove the decal & the phillips screw plug in the end of the adjustment knob. Then back the adjustment screw out bit by bit. Purge the reg gently between each adjustment to check for free flow.
Once you reach a point where the reg is gently free flowing, adjust it back in a bit (just enough to stop the free flow & then a tad more).

You should make the adjustments with the breathing adjustment knob screwed right out in the easiest breathing position.

Its not too serious if you set it a bit too fine and you get minor free flow on the next dive. You can just wind the knob in a bit to compensate, then when you get back home you can make a slight adjustment.

Apparently shops often shy away from setting the reg too fine for fear that it may free flow once it has bedded in, creating unhappy customers.

The lever height can also affect breathing performance and is adjusted by removing the low pressure hose and adjusting the plastic orifice in or out. You should not need to adjust this if the shop has done a half decent job. And you need to understand how to set the height.

Follow these instructions at your own risk, as Scubapro do not recomend that you make any changes yourself.

If anyone thinks I have given incorrect or incomplete information please speak up. I'm sure you will

bluey

 

[White Knight]

Thanks again for the info. I'll check out the link.

 

[Puffer Fish]

Other than the visual look, is there a difference between the SCUBA Pro G250 second stage and the SCUBA Pro S600 second stage? I have dove SCUBA Pro my whole life (25 years of diving) but my most recent SCUBA Pro reg I purchased (the S600) didn't perform like earlier regulators? I even had it rebuilt. It didn't breath as easy and sometimes "stuck" after being stored just a few days. I was wondering if it lacks in quality as compared to past regulator models and/or does the G250 still possess the tradition of SCUBA Pro excellence? If so, I'll buy one now. Thanks.....

I have owned all of the recent scubapro regs....I say "owned" because all I have left are G250v's...I found the 650 breathed easier than the 600, but leaked when upside down (a position I find myself in from time to time)...and the G250HP was, ok...(Well, I still have one as an octo)... but the 250V is a wonderful reg.

Part of the performance of a regulator is the size of the diaphram and how easy it is for the water behind it to get in and out....in this case bigger is better.. and more open is better... the 250V is great on both counts.

Style is a personal choice, and obviously adjustment is important, but I find the 250V to be every bit as good as my Apex T200 (almost identical designs), which was the best regular design regulator I have used. And I do have to adjust them close to the edge of freeflowing...

 

[White Knight]

Thank you Puffer Fish, Bluey and DA Aquamaster! All your words of wisdome was more than I hoped for. Check out the my thread......Atomic vs. SCUBAPRO

 

[DA Aquamaster]

In the old days, the SB regs came perfectly tuned out of the box? I then took it to a SCUBA Pro dive shop to have it serviced, but still it didn't breath as well as my past SB regs.

Way back in the day (early-mid 1980's) it was common for techs to tune the regs for minimum inhalation effort with just enough detuning to account for the seating groove that would develop.

That started changing with the move toward EU certifications and the frankly stupid freeflow prevention standards that required great breathing SP regs to be detuned. Now, regulator adjustment is done to factory specs that are well above the minimum inhalation efforts the regs can achieve.

In addition in 1994, Scubapro decided to go with plastic orifices that are not nearly as sharp as the previous brass orifices. The end result was a loss of sensitivity that mattered prior to the EU standards, but now had no real impact - unless you still liked to tune the reg for maximum performance.

At least the G250V has a metal orifice, so it is a step in the right direction and the reg is at least again capable of superb, rather than just very good, performance.

 

[redacted]

I recently serviced my wife's S600 (old style) and was quite surprised at how low I was able to set the cracking pressure with adequate stability. I dive mostly old SP metals and the S600 cracking pressure looked (in the sink) to be .2 to .3 inches less than I can tune my 156s. So that got me to thinking about the diaphragm size variable. It seems to me that performance will suffer if the diaphragm is either too small (too much vacuum required to operate it) or too large (too sensitive to environmental variables). I also have R-series regs with both the larger and smaller diaphragms and tend to get better performance from the 190 than the smaller one. But I am not convinced that this is effected by diaphragm size or some other variable (like how the poppet & spring sit in the housing and body. If we ever get a rainy day in Cen Tx maybe I'll spend some time swapping parts around to see if I can detect any differences.

BTW, one of my buddies dives older G250s and it is hard to detect any performance differences between them and my 156s. One thing common to all is that the user adjustment allows them to be adjusted very aggressively to the point where a slight freeflow is easily initiated but controlled with the adjustment. Surprisingly, the D-series seem to breath every bit as good as the S600/G250/156 and seem to be quite stable even without any user adjustment capability. But they do seem to be capable of setting higher levels of positive pressure breathing which effect WOB. I may have to build a manometer so I can objectively measure cracking pressure differences. The DIY bathroom sink just does not permit a comparative measurement with such different designs.