Any problems with R190/R290 and Mk25/S600?

[DocDAT]

Hi, the reason I ask is because I remember reading something about balanced first stages and the need for both octopus and primary 2nd stage being balanced. So is this applicable to the Mk25 and S600? Would they work perfectly with a R190/R290 octopus?

Another question: What's the difference between the R190 and the R290? They are sold at the exact same price by my local scuba dealer.

Thanks.

 

[redacted]

No problem using the R190 on a Mk20. I believe it is the other way around that SP recommends against (high performance 2nd like the G250HP on a low performance 1st like the Mk2). I don't know the difference between the R190 and the R290 other than you can't get free upgrades. And there may not even be any difference. As far as I can tell from schematics, SP introduced the Air2 4th Generation as a marketing ploy as I could find no change (in part numbers) from the most recent 3rd Gen schematic.

 

[DA Aquamaster]

Actually, SP will sell you any second stage with any first stage on a special order basis and they will work fine. My deco reg of choice is a Mk 2 or MK 3 first stage with a Balanced Adjustable or G250 second stage. Scubapro just creates certain packages to create entry level, intermediate and advanced (read inexpensive, sorta expensive, and make you think about expensive) combinations.

Dealer advice to the effect you should not use an unbalanced second stage with a balanced
first stage has everything to do with marketing and selling more expensive balanced octo's.

 

[rescuediver009]

I believe that the confusion about mixing and matching balanced stages originated from the fact that it is not the best idea to match an overbalanced first stage to an unbalanced second. None of which apply to Scubapro (as I recall).

Some companies like Apeks simply made all their second stages balanced to go with all their overbalanced first stages.
This is not to say that an unbalanced second cannot be mated to an overbalanced first. It just means that it will have to be detuned.