What is a great first stage for diving two Scubapro 109s

[Justin Phillips]

I got some fully serviced 109s and I am diving with a late model mk5 but I want to figure out a permanent great first stage to continue to dive with. Is the MK 17 the way to go or should I spring for a 25. I am in Wisconsin so the water can get cold when you go deep. I really like the 109s just want a strong first stage to grow with for many years.

 

[Justin Phillips]

Also should mention the 109s have been upgraded and converted

 

[Eric Sedletzky]

if the 109’s have been converted to balanced regs with S-wing poppets then any 1st stage will do, even another brand. Second stages are stupid, they don’t know what first stage is supplying them. As long as they get their 135-140 IP they are happy and don’t care.

 

[Ghost95]

If the Mk5 is the 5port turret, keep diving that. Classic chrome belongs together.

 

[Angelo Farina]

If the Mk5 is the 5port turret, keep diving that. Classic chrome belongs together.

I entirely agree. The only problem of the MK5 last version is that converting to DIN is a bit tricky, if you do not find its original DIN kit.
I managed to convert two of my MK5 to DIN using the inexpensive current Scubapro universal conversion kit (39 eur) by adding a calibrated 2.1mm metal ring for limiting the penetration of the screw inside the reg body, but it is an out-of-spec mod that frankly, as an engineer, I cannot recommend.
So if you want a proper first stage I recommend a MK10 with the SPEC rubber boot and properly packed with silicon grease. This remains the best SP piston reg ever built for cold water diving.
And the service kit for the MK10 is still easily available.
The MK10 is easily and safely converted to DIN using the current SP conversion kit.

 

[happy-diver]

The semi plastic conversion kit is ugly and does not suit, find a full brass one

 

[James79]

As @Ghost95 said, the Mk5 is just fine. For true cold water where freezing up the 1st stage is a legitimate concern, @Angelo Farina 's recommendation of a SPEC sealed Mk10 is spot on. If you want to go with similar vintage, but don't mind brand swapping, the Conshelf series from Aqualung are rock solid diaphragm regs.

Respectfully,

James

 

[lexvil]

The MK 17 is an excellent first stage, put a couple of G260 on it and hang the 109’s and MK 5 on the wall

performance wise the MK 5 /109 can still hang in there with the best of them and you’re diving fresh water so that will help keep their looks.

the mk5 is getting pretty long in the tooth and there are some parts issues but there are a lot of them around to salvage parts from. An upgraded MK 20 is good but I thing they were all satin finish, a later MK 25 will match the shine.

 

[Justin Phillips]

I will upgrade the 109 at some point but they are cost effecting jumping off points that are pretty great. I found a guy that only sells super clean 108 and 109s that he has fully reworked. I think based on a great offer I am going to do MK25 and 109s for now. A G260 would be a great upgrade to watch. A fully serviced and clean MK5 will get me back in the water with my own equipment next weekend and the MK25 and 109 will last me the summer with a mix of fresh and salt water.

 

[Justin Phillips]

I also have a Mares Abyss and M22 being serviced I want to compare to the 109 as well