Piston vs. balanced diaphragm for 1st stage

[a-cut-above]

My son just got certified and I am looking to buy an entry level regulator for him. We are recreational divers; the coldest water being Monterey. No technical diving planned, but wrecks at known local/tourist sites, vacations, etc. I have an MK10/D400. It's been "old reliable" over the years so I never thought much of new equipment. I would like a quality, simple rig for him. (The LDS sells Scubapro, so I would like to stick with that brand to avoid repair hassles.) Is there a quality/reliability/longevity difference in piston vs. diaphragm 1st stages? I would spend a little extra to get a bullet proof regulator but I don't think a high-performance rig is needed. So, MK 2,11,17, or 25?
Re: the 2nd stage, same thing, reliable and easy to repair (KISS approach: Keep It Simple Stupid). R295, R395, S555, or G250? When reading the tech specs and features, I have a hard time differentiating important stuff (worth paying for) from marketing fluff. Thank you in advance.
Dave

 

[redacted]

To get anything comparable to your rig will probably mean an expensive, high performance reg. Or you could look for a used setup like yours for a much more reasonable price. It is pretty hard (and expensive) to beat an old Scubapro D-series reg.

 

[DA Aquamaster]

I'd be happy to sell you a freshly serviced Mk 10 D400.

 

[darkarchangel]

I would sugest the MK17 and S555. The MK17 is preatty much bullet proof and the S555 is the same thing as a S600. The Mk 25 is a great first stage but lately i am using my MK17 more i Just did the swap of second stages.

 

[halocline]

If you want cheap and bullet proof, a used MK2/R190 (probably less than $100) is hard to beat. OTOH, if DA Aquamaster is offering to sell you a MK10/D400 serviced by him, I'd jump on it because you'll get a superb reg in better-than-factory tune.

 

[hudson]

A sealed first stage will require less cleaning come servicing time, but it will not necessarily last longer before it needs service, because the seat will wear out roughly at the same rate. And then cleaning is really the technician's problem From your list I would only consider the MK2 or the MK17, with MK17 having an edge the deeper you go. For second stage, G250V would be my only choice as it will breathe much nicer than the Rxxx series, and that lends itself to the MK17+G250V combo. So either that or DA's offer would be great options.

 

[Islandheart]

Jump on DA's offer !!!!!!!!!!!!

 

[renpirate]

If you want to go really cheap and bullet proof, then a MK2 with the R295 is probably your cheapest route. The MK2 is an unbalanced piston reg with few internal parts making it less likely to have a problem, but it won't breath as well, especially at the lower pressure at the end of a dive. The R295 is an entry level unbalanced second stage, also making it simple, but not a great breather.

I would either buy the reg set from DA myself, but if you want to buy from the shop I would recommend the MK11. The MK11 is a nice balanced diaphragm reg. It will breath better than the MK2 and and is less likely to free flow when the water temps get below 40 degrees. It also has 2 high pressure ports giving you the flexibility to have both a wireless transmitter for a computer and a console or analog gauge as a back up. As far as breathing characteristics, you won't find a real difference between the R295 or R395, the only difference is the VIVA adjustment. However, if you want to spend a little more money, the S550 is a balanced second stage and will breath better.

 

[Belce]

I think that really any of the Scubapro reg combinations you could get would suit your needs. You could even pass down your set to your son and get a new set for yourself

There is DA's offer that would allow you to dive father/son reg sets as well.

If you want to go brand new for the kid a mk11 or 17 with a G250 or S555 <pick one from each side> would do as well.

Or I think perhaps an even better suggestion, tell your son you will spend x dollars for a reg set of his choice, there is no benefit coming in under budget (meaning he can't pocket the balance) and if he wants more expensive it is from his pocket to make up directly or overtime. It is his life support system and should be the diver's choice. As an experienced diver and father you can guide and discuss the selection.

 

[Packhorse]

the S555 is the same thing as a S600.

Is it?
I thought the 555 was non user adjustable while the S600 is adjustable. To me that is a huge difference.