cold water use and most robust

[Scuba fryd]

I am looking for a new regulator
and we're looking at the XTX 50 dst or the MTX either r or rc version
but I can't decid.
my diving is sidemount in denmark with water from 1c to 19c i dont travel much to dive so wheigt is no issu

dkk to usd 6,53dkk = 1 usd
The price is XTX50 SIDEMOUNT KIT 10.356dkk
MTX-R sidemount kit 10.600dkk
MTX-RC were i buy singel tank longhose set up and a extra first stage. 11.600dkk
153 usd in defrince

since the price is so close and i cant realy see much defrinds other than the MTX aparently being even more robust and better at cold water
i were thinking to just go with the biggest one

but a cuppel of questions
is the adjustment even used i dont personaly thuch it more than mby every 20th dive or so
and is the cracking adjust and venturi control a weak point of the reg? dose it give a new place for sand and things to come in and mess with the reg or am i overthinking

i hope i explaned it good enough

hope to hear a good debate and if there is anything to think about or weather its just get the big one with such a tiny defrince

 

[davehicks]

Personally i would get the 2nd stage with the adjustment knob and get a matching pair.

There are some good considerations in this article:

Thread 'How to Choose a Regulator' Info - How to Choose a Regulator

 

[Mobulai]

if it’s a choice between these regs only, without including other options; anf given your coldwater diving, I would say get the MTX (R or RC)
The fins will greater improve on the icing of the first stage, way more surface area for heat exchange than the DST
I don’t dive water colder than 10 degrees (that’s my min, my avg is 21), and that’s rare — so can’t assess icing concern well enough

Can’t speak for R vs RC; nor the 2nd stages in general; I personally have never used them
Not a fan of the (X)TX 2nds as they don’t have good barrel stabilization (what I read), I only got my first Apeks 2nd (TX50 used) just yesterday out of like 100 2nd stages
Don’t know if the MTX ones are better in that front (edit: checked schematics looks same as xtx)
But.. the EVX is coming out soon; the promotion material emphasizes on the new improvement barrel stabilization so maybe you wanna wait and see what 1st stages they will pair it with (MTX vs DST)

My personal stance on knobs/levers is knob good, combo knob boo (that changes both Cracking effort and Venturi at the same motion) but better than no knob/lever
I dislike the ones that have Venturi „flap“ around the barrel (like apeks and SP a700) vs dedicated vane (like most SP 2nds); they collect more sand in their crevices

 

[DiveLikeAMuppet]

Both with work in cold water. DST+XTX-50 tends to be cheaper because you don’t pay as much w*nker premium to Apeks, internally the regs are identical - shop around.

 

[Scuba fryd]

if it’s a choice between these regs only, without including other options; anf given your coldwater diving, I would say get the MTX (R or RC)
The fins will greater improve on the icing of the first stage, way more surface area for heat exchange than the DST
I don’t dive water colder than 10 degrees (that’s my min, my avg is 21), and that’s rare — so can’t assess icing concern well enough

Can’t speak for R vs RC; nor the 2nd stages in general; I personally have never used them
Not a fan of the (X)TX 2nds as they don’t have good barrel stabilization (what I read), I only got my first Apeks 2nd (TX50 used) just yesterday out of like 100 2nd stages
Don’t know if the MTX ones are better in that front (edit: checked schematics looks same as xtx)
But.. the EVX is coming out soon; the promotion material emphasizes on the new improvement barrel stabilization so maybe you wanna wait and see what 1st stages they will pair it with (MTX vs DST)

My personal stance on knobs/levers is knob good, combo knob boo (that changes both Cracking effort and Venturi at the same motion) but better than no knob/lever
I dislike the ones that have Venturi „flap“ around the barrel (like apeks and SP a700) vs dedicated vane (like most SP 2nds); they collect more sand in their crevices

what do you mean by barrel stabilisation ?
i looked at the new evx but i need a set with swivel 1 stages so it wasn't really in play for me anyway.

are there any other reg you if would be better ? i were thinking apeks just for the availability in service.

 

[Mobulai]

i looked at the new evx but i need a set with swivel 1 stages so it wasn't really in play for me anyway.

Oh I haven’t it’s dedicated 1st stage yet so my bad.. yeah I prefer swivel as well

what do you mean by barrel stabilisation ?

This is a feature of longevity/service, so there tends to be a broach at the hose end of a 2nd stage barrel (inlet tube/valve) that prevents it from rotating inside the housing

Here you can see an Apeks on the left (2 flats + 2 archs) vs Scubapro (square)

And here is the housing side for both
Apeks (a bit flimsy)

Vs Scubapro

Again, till last week I had no Apeks 2nd stages so.. I haven’t personally experienced issues with that; but I did read that sometimes the hub that stabilized the barrel wears out and then some rotation occurs where the demand lever isn’t parallel to the diaphragm
But of the service tech is careful theoretically it should last (look at this ancient TX50 that looks like new)

For alternative choices:
I personally have a bias towards Scubapro (for DIY service reasons), I got myself the mk19/g260 sidemount kit; but since I also don’t really dive cold water I switch out sometimes to mk25 (old not evo) 1st stages

Since the DST and MTX 1sts internals are the same, that means no replaceable orifice (longevity issues) vs all Scubapro diaphragm regs (11, 17, 19)

Mares are also great for coldwater (I hear)

Do check 1st what other options are out there in your local (service/part availability…)

 

[Scuba fryd]

Oh I haven’t it’s dedicated 1st stage yet so my bad.. yeah I prefer swivel as well


This is a feature of longevity/service, so there tends to be a broach at the hose end of a 2nd stage barrel (inlet tube/valve) that prevents it from rotating inside the housing
View attachment 894832
Here you can see an Apeks on the left (2 flats + 2 archs) vs Scubapro (square)

And here is the housing side for both
Apeks (a bit flimsy)
View attachment 894833
Vs Scubapro
View attachment 894834View attachment 894835

Again, till last week I had no Apeks 2nd stages so.. I haven’t personally experienced issues with that; but I did read that sometimes the hub that stabilized the barrel wears out and then some rotation occurs where the demand lever isn’t parallel to the diaphragm
But of the service tech is careful theoretically it should last (look at this ancient TX50 that looks like new)

For alternative choices:
I personally have a bias towards Scubapro (for DIY service reasons), I got myself the mk19/g260 sidemount kit; but since I also don’t really dive cold water I switch out sometimes to mk25 (old not evo) 1st stages

Since the DST and MTX 1sts internals are the same, that means no replaceable orifice (longevity issues) vs all Scubapro diaphragm regs (11, 17, 19)

Mares are also great for coldwater (I hear)

Do check 1st what other options are out there in your local (service/part availability…)

Ahh okay, that makes sense. From what I see, Mares is not that easy to find service for everywhere, and the same with Atomic.
And for a principle, I just don't like Scubapro (don't ask why I don't have a proper answer),
Aqualung, I haven't even looked at.
The apex i would have serviced at a service center since they offer a lifetime guarantee on the components, so i wish to keep that. Maybe I'll try self-service later if i get a used XTX50 since it seems less complex and is a bit cheaper.
but i am thinking I'll just go with the MTX-RC since it's only a 152 USD difference, and my hopes for deep and ice diving would then not require another set.

But you say that you can't change the orifice? How come, and am I correct that the orifice is the plate that regulates the pressure?

 

[Mobulai]

And for a principle, I just don't like Scubapro (don't ask why I don't have a proper answer),

I get it it’s a vibe — I used to dislike them a lot around when I got my 1st reg; I picked up on it when I started DIY service (started with old cheap used ones, and it kinda grew from there)

But you say that you can't change the orifice?

the HP seat is the one that you change during service, it seals against the orifice/volcano, which can get dings over years and years (also some service „tecs“ sometimes ding them)
In Apeks regs that’s part of the body
For SP and DR, that’s a separate part that can be replaced on its own
Being buried inside the body makes it hard to restore/ impossible to replace
But that’s a matter of depreciation over the life of the reg

View attachment 522997

This is an example of a DST with a damaged crown. Too much damage for polishing.
In this case, the IP creep was fast, reaching over 17bar within a minute.

I'd say: if you can see the damage, replace the housing. I got a new one for €45, which ain't much when you consider this is life supporting equipment.

 

[steinbil]

Again, till last week I had no Apeks 2nd stages so.. I haven’t personally experienced issues with that; but I did read that sometimes the hub that stabilized the barrel wears out and then some rotation occurs where the demand lever isn’t parallel to the diaphragm
But of the service tech is careful theoretically it should last (look at this ancient TX50 that looks like new)

Yeah, if you're careful when tightening/loosening the nut that locks the barrel in the housing, it shouldn't be a problem, but if you hold the housing and use force on the nut you run the risk of digging in to the plastic and making the barrel a little less stable in the reg.

@rsingler showed me the way to do it is to fully tighten the adjustment knob on the second stage and hold that for leverage against tightening the nut instead of holding the housing, and you should avoid the problem altogether.

I personally have a bias towards Scubapro (for DIY service reasons)

That's interesting. The Apeks regs seem very easy to service, while the SP regs seem a little more involved to me. Either shouldn't be terribly difficult, though, from what I can gather.

But you say that you can't change the orifice?

Correct. The orifice of most of the Apeks regs is a part of the reg body - meaning you would have to replace the entire reg body if it is badly damaged. For lighter scratches it's possibly to restore if you know what you're doing, but most reg techs won't do that as it's not recommended by Apeks. However, the orifice shouldn't get damaged unless in the hands of a sloppy reg tech...

The Apeks FSR(XTX200) 1st stage does have a replaceable volcano orifice. So if that matters to you, and you want an Apeks, it's a very solid reg.

All of the Apeks regs perform very well in cold water, and they are one of the most common regs here in Norway.

 

[Mobulai]

That's interesting. The Apeks regs seem very easy to service, while the SP regs seem a little more involved to me. Either shouldn't be terribly difficult, though, from what I can gather.

Parts cross compatibility between regs (not just the service parts but also body parts
IDK, I started with a couple of mk10/g250s to learn on when I took the @rsingler class, and things piled up from there (Sunken cost pov)
But yes Apeks regs are also easy to service (except for that damned environmental cap)