x650

[liberato]

SP has returned my x650 today...

That is good news. Since you got your X650 back instead of a replacement S600 that implies they have a solution implemented. It only took 2 weeks for yours so I should be expecting mine sent in much earlier any day now...

 

[liberato]

... Now they admit to some problem with no solution but will gladly give me a new 600 to replace my X650. I will be going to get my new unit today...

Oh, now it looks like Scubapro Europe and Scubapro USA are on different pages...

 

[DA Aquamaster]

Hi again

SP has returned my x650 today. This is what it said on the Repair note (If it makes any sence to you):
1. BALANCE CHAMBER, PKG
2. DIAPHRAGM ASSY, X650
3. POPPET ASSY, X650
4. LEVER, X650
5. DECAL ADJUST. KNOB

I guess it means that they have replaced a few parts and adjusted it.

I will be taking it diving tomorrow, to see how it works after the repair. I´ll get back to you to tell you how it worked.

-Karsten-

The original issue with the X650 was with the lever which was wearing on a plastic bushing and causing cracking effort increase. This was supposed to be redesigned with more rounded edges to avoid the problem.

Replacing the balance chamber and poppet assembly are normal annual service items. However, the lever and diaphragm are parts that are not normally replaced and suggest some upgrades.

The decal is just a trim part.

And on my X650, despite a fax indicating the reg was to be shipped, SP is now saying it is backordered.

 

[Hoosier]

I am so confused with X650. As we see, many people experienced the same problem (no matter what it is) that SP also recognized. But, in recent issue of Scuba Diving, they rated X650 as this year’s best reg. So, who is delivering a right information?

==============================================================
 SCUBAPRO didn't respond. It has two new regulators in its 2004 catalog--the MK25/X650 and the MK25SA/S600. The MK25SA/S600 was not yet off the production line at the time of testing, but the MK25/X650 was available. Because Scubapro is a major manufacturer with widespread U.S. distribution, we purchased one from a local dive store to test.  http://www.scubadiving.com/gear/regulators/class_of_2004/6/
==============================================================
SIMULATOR SCORES: 20 out of a possible 20. > ERGO SCORES: 57 out of a possible 70.
Scubapro's MK25 balanced piston first stage, coupled with the new X650 balanced second stage, was this year's top performer, earning a perfect simulator score for the lowest work of breathing across the test board and the highest total score for ergonomic performance. It's the only reg test divers rated Excellent for ease of breathing in the swimming position, and it got Very Good scores just about everywhere else.

Test divers liked the first stage's low-pressure port swivel turret, which greatly simplifies hose routing. The dive/pre-dive switch is clearly marked, so you can tell at a glance which position you're in. It's also easy to use when wearing gloves. The same goes for the breathing resistance knob.

The MK25/X650 earned an overall Very Good rating for clearing, especially using the blowing method. However, test divers considered the purge cover to be excessively stiff, making it difficult to activate the manual purge. But this was the only drawback they found on a very sweet reg.
http://www.scubadiving.com/gear/regulators/class_of_2004/3/

 

[liberato]

...So, who is delivering [the] right information?

No one is saying that it is not a great performer new out-of-the-box. Only that for an unknown but significant percentage of owners the performance degrades very quickly. The symptoms of failure are always the same and a similar or same problem was recognized and generally thought to have been fixed last year right after introduction.

 

[Denmark]

Hi again.
I took my x650 (the one returned from SP after service) on a pool dive today. It worked absolutely perfect!! It breathed so easy! By far the most smooth breathing reg I have ever tried (and I´ve tried a few). Looking forward to be taking it diving in the sea tomorrow.

So it seems like SP has fixed the problem. I´ll give you a report after the reg has passed the magic 20 dives again ;-) But so far It´s looking sweet!

-Karsten-

 

[underwater daphne]

Hi again.
I took my x650 (the one returned from SP after service) on a pool dive today. It worked absolutely perfect!! It breathed so easy! By far the most smooth breathing reg I have ever tried (and I´ve tried a few). Looking forward to be taking it diving in the sea tomorrow.

So it seems like SP has fixed the problem. I´ll give you a report after the reg has passed the magic 20 dives again ;-) But so far It´s looking sweet!

-Karsten-

yes, please let us know, i'm thinking of getting one next year.

 

[liberato]

I wonder how the European beta test is going. Karsten, did you get very many dives yet on the fixed version? Anyone else have a new X650 yet? It has been almost 3 months since I sent mine back and declined the S600 substitute. Don't mind waiting. Wouldn't even mind testing new version.

 

[Denmark]

Hi liberato!

The reg is performing just fine! There has been no problems since I got it back from service. I have done about 10 dives with it since the service.

So far it´s looking good!

Wonder why it takes so long for you guys in the US to get the reg. serviced?? Is SP not a big brand over there?

-Karsten-

 

[Compressor]

Thanks for the detailed explanation. It is very useful to most of us.

The advantages of the X650 have a lot to do with the Darth Vader wierd case design and are not immediately obvious unless you understand the concept of case geometry fault.

The X650 appears to use the same basic air barrel and poppet assemblies as Scubapro's more conventional balanced reg designs and on the surface would not offer any real improvement - except for the case geometry and that can make a great deal of difference in terms of how much of that really low cracking effort you can really use in the water.

For example, even a very old Balanced Adjustable second stage can be updated using the same poppet a G250, G500 or S600. Equipped with this poppet, all four regs can be adjusted to give a very low cracking effort under 1.0 inch in the in the .7 range out of the water. However, the regulators adjusted to that level of effort are not fully usable in the water without some diver adjustment to increase cracking effort as the cracking effort is not the limiting factor in the system.

In a conventional case design, the position of the regulator is critical. When the diver is vertical in the water, the top of the exhaust valve is about .2 inches lower than the center of the diaphragm and consequently the exhaust valve is securely seated by water pressure. When the diver rotates in the water to a normal swimming position with the reg angled down about 45 degrees, the top of the exhaust valve is now about .8 inches above the center of the diaphragm and this pressure differential bleeds air out the exhaust valve. And if the diver rotates further to a face down position, the difference in depth increases this pressure difference to about 1.25 inches.

What this means is that in a normal swimming position, a conventional second stage that is adjusted to a cracking effort of .7 to 1.2 on the surface will work ok when the diver is vertical but will freeflow slightly in a normal swimming position or when face down as the air leaking out the elevated exhaust valve will create enough suction to open the poppet and continue to supply air to feed the leak out the exhaust valve. So in the real world the diver ends up having to detune the reg by turning in the adjustment knob to increase the spring pressure and the cracking effort to the 1.2 to 1.3 range anyway to stop the slight freeflow of air out the exhaust valve.

With my own regs of this design, I adjust them on the bench for minimum cracking effort just because.... but I also recognize that on most dives I will end up with the adjustment knob turned in 2-3 turns if I want to set the reg up so that I do not have to mess with it during the dive.

So in short with a conventional case design and a high perfromance poppet you have a lot of potential low cracking effort performance that you cannot use in the water without a lot of adjustment every time you change position in the water. To make the second stage diveable in an adjustment free manner throughout the dive (or in the case of a non adjustable second stage where it cannot be adjusted) you are limited to a minimum cracking effort of around 1.2 to 1.3 inches if you are going to avoid a freeflow in the worst case face down position. A lot of people talk about how low their reg's cracking effort is on the bench, but it is kind of irrellevent if it cannot be used in the water without position related freeflow issues.

With a more unconventional case design like the D400, the exhaust valve is located in the center of the diaphragm and the worst case pressure differential is only .6. And as an extra benefit, this worst case positon occurs when you are rotated 135 degrees from the vertical and rarely occurs in the water. So a D400 adjusted to provide a cracking effort of .6 could be used throughout the dive with no adjustment required and with about half the real world cracking effort of a G250, G500 or S600. It's a very real advantage that never really shows to it's full subjective effect on a work of breathing chart nor was it an advantage SP every really marketed but one that is obvious is you dive a G250 or S600 and a D400 side by side. The D400 just "feels" better.

My first thought when I first saw a picture of the X650 was "oh goody, an angled diaphragm with a co-axial exhaust valve just like the D400". My second thought after looking closer was "oh darn, it has a separate exhaust valve, gimme back my D400."

I am now firmly middle of the road about it until I get to dive with one. I have still not seen one in the flesh but it does appears to have its diaphragm angled 30-45 degrees and the case is relatively flat in terms of diaphragm to exhaust valve distance. So while it does not appear to offer the same extreme degree of CGF advantage as the D400 in terms of case/diaphragm/exhaust valve design, it should still allow a lower usable cracking effort of under 1.0 inch without being subject to freeflow in the face down position.

With the same poppet assembly and potentially low cracking effort as the G250, S600, etc combined with a case design that appears to reduce CGF issues, it should be a very good performer in the water. The X650 like the D400 also appears to have a large exhaust valve and should have lower exhalation resistance than SP's other conventional cased second stages. It also has a real exhaust T, unlike the D400, so it should have less bubble interference than a D400.