SP R190 vs R295 octo

[DiverDave65]

Considering the purchase of either the SP R190 or R295 octo for my nephew's first reg....any thoughts or comments on these two octo's??

Thanks in advance.....I should add they will be attached to a SP MK17/x650.

Fire away!!

 

[ajduplessis]

Both are downstream and will work fine. I have the R295 and used it as primary to test performance. It works great.

 

[kanonfodr]

I would recommend either reg as a backup, I personally own both and cannot find major fault with either model.

That being said, I would recommend getting a different primary as the x650 is incredibly prone to freeflow. You can search the board for threads about the subject. I replaced mine with an S555 2nd stage for that reason. But I will say that the MK17 is a great first stage with a good reputation for reliability in some extreme environments.

Peace,
Greg

 

[DA Aquamaster]

"Incredibly prone to freeflow" is a bit of a mis-statement regarding the X650. It does have a case geometry fault issue that the D series regs it replaced did not, and is has a very large and flexible exhaust valve that improves the work of breathing scores. Consequently if adjusted below an inhalation effort of about 1.0-1.1 inches of water it can tend to dribble a tiny amount of air out the exhaust valve between inhalations. This is a distinct poossibility as the poppet assembly itself can easily produce inhalation efforts are loas .6 inches of water.

They are also different from the G and S series regs in terms of air barrel and lever design, so it takes a little different approach to adjust them properly and it took me a while to figure out how to get reasonably low inhalation efforts out of it without the very slight freeflow tendency.

The adjustment issue is ironic as one of Scubapro's main reasons for killing the D400 was that it was different to adjust, so the X650 accomplished basically nothing in that regard. And that had a lot to do with it's early demise.

That said, I own two of them that I use on stage bottles and when properly tuned they breathe and perform great. If it were freeflow prone, I would not be using one 2000' back in a cave.

The X650 is also very solid performer in very cold water, much more so than the S600 and a better match for the Mk17 if very cold water dives are anticipated.

 

[kanonfodr]

DA Aquamaster:

Are those adjustments possible for the average diver to accomplish, or does my X650 need to be turned in to a tech? The only times I was able to get my reg to stop free flowing was to adjust it all the way down, Pre-Dive and inhalation adjustment bottomed out. Would appreciate the info about turning it once again into a trustworthy regulator.

Peace,
Greg

 

[NAUIwowee]

Internally, they are the same regulator. Both use the same service kit. The only difference between the two is the body case; so, you just have to decide whether you prefer the larger, classic style of the R190 or the more compact R295. Also, the R190 has a diver-adjustable VIVA, which can help prevent free-flow when used as an octo, while the R295 has a fixed VIVA. I used to own an R190/MK2 as a pony bottle reg and never had any problems with it.

 

[DA Aquamaster]

DA Aquamaster:

Are those adjustments possible for the average diver to accomplish, or does my X650 need to be turned in to a tech? The only times I was able to get my reg to stop free flowing was to adjust it all the way down, Pre-Dive and inhalation adjustment bottomed out. Would appreciate the info about turning it once again into a trustworthy regulator.

Peace,
Greg

I am on the road until the 16th, but PM me after that and I can take one apart, send some pictures and talk you through the process. It is a single adjustment design in the sense that orifice adjustment controls both spring pressure and lever height, but there are a couple things you can do to increase the spring pressure independent of the lever height.

Needing to screw the adjustment knob in all the is potentially symptomatic of needing a bit more spring pressure, but adjustment needs to start with the orifice to ensure the lever position is correct.

 

[DA Aquamaster]

Internally, they are the same regulator. Both use the same service kit. The only difference between the two is the body case; so, you just have to decide whether you prefer the larger, classic style of the R190 or the more compact R295. Also, the R190 has a diver-adjustable VIVA, which can help prevent free-flow when used as an octo, while the R295 has a fixed VIVA. I used to own an R190/MK2 as a pony bottle reg and never had any problems with it.

I have always preferred the R190 to the smaller cased R380/390/290/295 regs. The internal parts are identical and the major difference is the larger case that also accommodates a larger diaphragm.

In effect, the same pressure differential across a larger diaphragm with significantly more area means you have much more power available to actually operate the valve. Looking at it differently, you have the same power available at a lower pressure differential which can, with proper tuning, equate to lower initial inhalation efforts.

That said, I have found a fairly wide range of variation in the R series. Some breathe superb and others not so well. The latter occurs when the spring used just is not well mated to the other parts and the solution is normally to change to a lighter spring.

 

[redacted]

That said, I have found a fairly wide range of variation in the R series. Some breathe superb and others not so well. The latter occurs when the spring used just is not well mated to the other parts and the solution is normally to change to a lighter spring.

I found that variance even between R190s. I believe the problem is that the classic downstream design doesn't really provide precise poppet operation. That is, when the lever is depressed, the poppet is lifted but there can also be some sideways forces that create friction between the poppet and the housing. Plus, there are a number of versions of both the poppet and the housing which may have an effect on performance.

I had some success with a poor performing R190 by changing the orientation of the poppet in the housing, but maybe I just got a little lucky with that one.

Of course, as DA said, maybe all I really did was change the spring alignment to a more favorable position.

 

[DiverDave65]

Thanks to everyone for your replies and info!!