Is the Apeks MTX-RC really as good a cold water regulator as the MTX-R?

[Lt CHEG]

So I’m wanting to get into tech diving and the instructor that I’m interested in doing some training with suggested that I go with a diaphragm regulator, especially since I’m also thinking of getting an ice diving cert this year after I get my drysuit. I’ve always been a Scubapro piston guy and I’ve never had problems with my Mk20/Mk25. I am also planning on picking up a Scubapro Mk17 as a diaphragm reg to probably use with an OTS full face mask for public safety diving in the warmer months. Having said that I also want to try out some Apeks gear and a regulator from a company known for their diaphragm regs before deciding which regs to build a twinset with. I like Poseidon gear too, but I wish their first stages had swivels for twinset setups.

So I will probably be adding a few regs to my collection this year and keeping some dedicated to certain roles, so I don’t mind having some diversity. I will probably buy an Apeks MTX-R, MTX-RC or XTX 200 soon. I love the idea of the MTX-R’s acceptance by the Navy but it looks like the MTX-RC is more versatile. So the question is, does the MTC-RC give up any performance, particularly in the coldest of water, to the MTX-R? Which would you buy? The cost difference in any isn’t enough to matter to me. Thanks for your input.

 

[JackD342]

Since it was designed for military requirements and not for recreational divers, the Work Of Breathing on the MTX-R is 1.75 joules/liter, which is well over double that of other Apeks regulators, and has no venturi control or opening effort control to change that spec.

I have asked for WOB on the MTX-RC, but nothing has been provided yet. It is my reasonable belief that when you detune the opening effort (and perhaps put the venturi in the "-" position) that you will have the same performance as the MTX-R. But when you are diving less extreme temps, you can enjoy an easier breathing set by adjusting for it with the added controls.

The US Navy EDU has not yet signed off on the MTX, but so far so good in their evaluation process. It was designed to meet their new requirements, and more than likely will satisfy them.

 

[Lt CHEG]

Since it was designed for military requirements and not for recreational divers, the Work Of Breathing on the MTX-R is 1.75 joules/liter, which is well over double that of other Apeks regulators, and has no venturi control or opening effort control to change that spec.

I have asked for WOB on the MTX-RC, but nothing has been provided yet. It is my reasonable belief that when you detune the opening effort (and perhaps put the venturi in the "-" position) that you will have the same performance as the MTX-R. But when you are diving less extreme temps, you can enjoy an easier breathing set by adjusting for it with the added controls.

The US Navy EDU has not yet signed off on the MTX, but so far so good in their evaluation process. It was designed to meet their new requirements, and more than likely will satisfy them.

I actually really like the Poseidon XStream regs too, but I think that the swivel first stage is highly desirable. It seems like for ice diving those two regs are at the top of the list of regs to be considering.

 

[runsongas]

you can run poseidon jetstream or xstream 2nd stages with apeks DST or other first stages if you add an opv to either the hoses or the first stage. the poseidon first stages have an integrated opv.

 

[Lt CHEG]

you can run poseidon jetstream or xstream 2nd stages with apeks DST or other first stages if you add an opv to either the hoses or the first stage. the poseidon first stages have an integrated opv.

Do you really get all the benefits of the Poseidon system this way then? I thought that a big part (at least half) of what makes Poseidon regs so good was the first stage?

 

[runsongas]

the xstream first stage has some unique enhancements, but the servo in the 2nd stages makes a bigger difference

 

[Vicko]

I dived and dissasembled the mtx, it's not a good reg.

Bad materials used, questionable desing and worse wob than a ****** rental reg.

 

[michael-fisch]

Tech divers have been using DS4 and DST 1st stages for over 23 years. Popular 2nd stages have always been TX50, TX100 2nd stages and all their descendents.

The MTX, along with all it's modifications, is unknown in the tech diving community, maybe for a good reason.

I'd avoid it like the plague, or at least athlete's foot, untill you hear glowing reports from the WKPP, US Deep Caving Team, EKPP, and the extreme tec/cave divers from England Finland and Sweden.

Michael

 

[Lt CHEG]

Tech divers have been using DS4 and DST 1st stages for over 23 years. Popular 2nd stages have always been TX50, TX100 2nd stages and all their descendents.

The MTX, along with all it's modifications, is unknown in the tech diving community, maybe for a good reason.

I'd avoid it like the plague, or at least athlete's foot, untill you hear glowing reports from the WKPP, US Deep Caving Team, EKPP, and the extreme tec/cave divers from England Finland and Sweden.

Michael

Are you suggesting that the XTX 200 might be a better choice? Would it be a good cold water regulator for ice diving?

 

[Coztick]

Are you suggesting that the XTX 200 might be a better choice? Would it be a good cold water regulator for ice diving?

Any sealed Apeks 1st is up to the task.
I like the decades of proof of design as well as being used by a majority of cave divers as evidence.
New and unproven is never a good choice in life supporting equipment.