Mares Abyss 52 and Oceanic EOS FDX-10

[kebosatu]

Hi All,

Nice to meet everyone here. I've been browse through this forum for quite sometimes, but I just registered and this is my first post.

Thinking of having regulator.
My dive profile:
- Warm water. 18C/64F the lowest.
- Max depth 30m

Currently comparing these 2 regulators:
Abyss 52 (Seems pretty new product) vs EOS FDX-10 (Seems has good reviews, I choose it because of performance review + my basic gears are oceanic)

Would like to hear some inputs from you. what I've been wondering are:

Abyss 52:
1. No adjustment breathing knob. In fact all Mares product don't come with it.

• Does this mean less chance for poor set-up?
• Will the breathing gets more difficult when you are going deeper?

2. No Venturi for pre-dive. Is this important?


EOS FDX-10:
1. This is top of the class, but seeing so many people selling this product. Wanna hear the bad side of it?


Appreciate your inputs

-Kebo

 

[LeadTurn_SD]

Short answer:

• You'll be happy with either regulator.
• The Mares will not breath harder with increasing depth. As with every regulator, it is "depth compensating". In fact, a number of years ago the Mares Abyss (MR-22 Abyss) was used on world record deep dives.
• Poor setup can happen with either, based on the skill (or lack of skill) of the technician who services.
• However, poor setup will be less forgiving with the Mares Abyss. If not properly tuned, it will have really mediocre performance.

Long Answer:

The Mares Abyss 2nd stage has been around for many years. It is an unbalanced classic downstream 2nd stage. It does not have external adjustment to de-tune the 2nd stage like many current balanced barrel poppet 2nd stages do. The Mares 1st stage is balanced however.

The lack of external de-tuning controls on a 2nd stage does not automatically mean that the 2nd stage is "inferior" or will breath worse than a regulator that has these controls. Overall design and correct setup ("tuning") of the 2nd stage determines how well it breathes.

The advantages of having external adjustments is that the adjusting knob does allow the user to change demand valve spring pre-load and thus can allow the diver to "de-tune" the 2nd stage when needed. The venturi lever allows the diver to reduce the venturi effect to prevent surface free-flows (when the regulator is not in the diver's mouth).

Also, a balanced adjustable 2nd stage can breath just a bit better than an unbalanced, non-adjustable 2nd stage of similar design. The reason is that the adjustable regulator can be tuned right up to the very edge of a free-flow, with the understanding that the diver can de-tune the regulator slightly if needed.

A non-adjustable 2nd stage like the Abyss cannot be tuned quite this "hot", because if it starts to free-flow slightly during a dive there is no way to de-tune it. To de-tune a non-adjustable 2nd stage it will need to be removed from the hose, and tools are needed.

Also, a balanced 2nd stage typically has a lighter demand valve spring than an unbalanced 2nd stage, and this can result in a slightly better breathing 2nd stage (an over simplification, but essentially correct).

What I have found with my Mares Abyss 2nd stages is that they breath very well, but as I mentioned above that I cannot tune them quite as "hot" as I can tune my best balanced adjustable 2nd stages.

Does this mean that the Mares breathes worse than my other 2nd stages? Not really. It slightly out-performs some of my adjustable 2nd stages, and is just slightly outperformed by others. This is a function of engineering desing rather than being adjustable or not.

The difference is so slight that I can only tell if I use one as my primary and the other as my octo, and test them both underwater... and even then it is pretty close.

After that long reply, I do recommend adjustable 2nd stages over non-adjustable simply because you can de-tune them "on the fly".

And I have encountered Mares Abyss 2nds, straight from the factory, that are badly tuned. It does take a little extra time and effort to tune them correctly, and some techs don't do this.

Best wishes

 

[kebosatu]

Hi LeadTurn,

I really appreciate your time in writing this long reply. Completely got your points.

Since I have a tendency to get Mares Abyss 2nd, would like to understand few more things.

Though probably chance to get badly tuned 2nds is smaller than get a good one, definitely there still a chance I will encounter such case --If I understand correctly you have encountered badly tuned Abyss 2nds more than once--

How do you tell if your 2nds is badly tuned or is properly tuned? For those new to the regulator, probably one can't tell, and will think that it is what it is and assumes this is the optimal performance...

Could you share some on this?

Thanks,
Kebo

 

[LeadTurn_SD]

Hi LeadTurn,

I really appreciate your time in writing this long reply. Completely got your points.

Since I have a tendency to get Mares Abyss 2nd, would like to understand few more things.

Though probably chance to get badly tuned 2nds is smaller than get a good one, definitely there still a chance I will encounter such case --If I understand correctly you have encountered badly tuned Abyss 2nds more than once--

How do you tell if your 2nds is badly tuned or is properly tuned? For those new to the regulator, probably one can't tell, and will think that it is what it is and assumes this is the optimal performance...

Could you share some on this?

Thanks,
Kebo

Hi Kebo,

This will be a long answer. But I'll try to give you a way to test an Abyss without tools or gauges.

First, some basic information: All good quality 2nd stages that are functioning properly and "tuned" correctly should be able to provide more air flow that the diver would ever need. There will always be a very slight resistance during the first instant of inhalation; this is called the "cracking pressure", the amount of vacuum force that is needed to open the demand valve. Once the valve is open, there should very little additional force needed to open the valve the rest of the way and keep it open for as long as the diver continues inhaling. A well-tuned 2nd stage will seem to provide air so easily that the air flow begins as you think about inhaling. This is a slight exaggeration, but really the work of breathing should be not be any more than breathing normally on the surface, sitting in front of your computer and breathing though your mouth as if a regulator was in it.

Cracking Pressure is measured in inches of water. Lower is better. Most decent 2nd stages are "well tuned" at around 1.0 - 1.5 inches of water. But this varies among different 2nd stages, and there are other factors that effect the overall work of breathing.... and a regulator that has a lower cracking pressure may not necessarily breath better than one with a slightly higher cracking pressure. Finally, how low you can set the cracking pressure in a given 2nd stages is limited by case geometry and the design of the demand valve and seat.

What I noticed with the Mares regs I purchased (online) was that they were tuned very conservatively. They breathed like low end "rental" or "student" regulators; many dive shops will slightly detune rental regulators and regulators used by OW students to prevent them from being as prone to surface freeflows.

I bought 5 sets of Mares regulators online back in 2007, and I suspect they were only tested but not tuned by the dealer.

From the factory, the Mares Abyss regs were set at about 1.8 inches, Protons the same, and Rebel octos were set at 2.0 inches. And in all cases the demand levers were set a little too low. The Mares Abyss should actually be tuned at about 1.3 inches and still be "stable", and the Protons are pretty happy at about 1.2 inches.

I eventually re-tuned the 2nd stages, including setting the demand levers at the proper heights, and it was a difference of night and day in performance.

The only way to know a well-tuned reg from a detuned or poorly tuned reg is to have experienced the difference.

But the difference can be summed up as "Ohhhh..." and "Ahhhhh!!!" .

Be patient with me and take a moment to perform the following exercise:

1.) While sitting at your computer, say the word English word "Ohhhh", and without changing the shaped of your mouth, inhale.

2.) Now do the same thing, but say the English word "Ahhhh!!", and then inhale.

Feel the difference???

That is about how different the inhalation effort feels to me between a 2nd stage that is "cracking" at about 2.0 inches and a 2nd stage that is cracking at around 1.3 inches.

The Mares Abyss should be an "Ahhhh!!" experience, not an "Ohhhh...." experience

The Mares 2nd stages have two adjustments (orifice depth, which effects cracking pressure, and lever height) and they directly effect each other. The adjustments are not difficult, but do require a little extra effort from the technician when the regulator is being serviced. An inexperienced or lazy technician can miss the "sweet spot" with orifice depth and lever height, and end up with a mediocre result and not understand why.

If you buy from a good dealer who sets up and thoroughly tests the regulators, none of what we are discussing will be an issue.

If you end up buying the Mares regs and have further questions, please feel free to send me a PM or post on here. I'm not a "certified Mares technician", but I'm happy to fix their mistakes (just kidding, well, sort of).

Best wishes.

 

[rjk75]

LeadTurn,

Thank you for your excellent write-up. I’ve been following your comments for this and previous threads re: intermediate pressure (IP) settings and 2^nd stage tunings.

http://www.scubaboard.com/forums/re...ss-metal-42-cracking-pressure-adjustment.html

http://www.scubaboard.com/forums/regulators/413915-mares-abyss-42-pressures.html

This one’s very informative:
http://www.scubaboard.com/forums/ma...ate-carbon-42-regulator-service-canada-2.html

My situation is very similar to what you answered for Kebosatu. I have an MR42T (yoke) with Abyss 2^nd that I bought new from an LDS. I wanted this unit because:
o The 1^st stage is a diaphragm and is quite compact.
o The 2^nd stage body is mostly metal (i.e., minimal plastic).
o I borrowed an MR22T/Abyss the year before and really liked it.
o Mares products are available most everywhere in the world.
o I don’t care for 2^nd stage adjustment knobs—had another one that I was constantly fooling around with to no benefit.

My MR42T/Abyss was set up rather conservatively with that "Ohhhh..." feel on inhalation (good analogy) and so I got the LDS to adjust it to get that "Ahhhhh!!!" feel. That was great but after about 15 dives, the 2^nd started to free flow easily and leaked above water slightly. The LDS said the valve seat is "setting" a little because it’s new and subsequently fixed this. No problem.

In the future, I plan to adjust my 2^nd stage myself which I believe is easily done with the basic knowledge of how these things work. I’m quite capable of fixing most anything mechanical. I have the Abyss exploded diagram, two IP gauges (two for corroboration), other basic tools and your current and previous write-ups consolidated for reference.

My 2^nd stage is connected to the port marked “DFC” on the 1^st stage. (Mares claims a little more air flows out this port I believe.) I also have a Mares MV octo, an SPG and inflator hose.

My concern now is about the IP and breathability underwater. I have my IP set to 145 psi with tank at 2400 psi--I use mostly LP steels when possible and dive colder waters. (Mares recommends 142 to 148 psi for 2900 tank press.)

My Abyss breathes quite easily the way it’s set up now. Doing the “field” test in the pool for cracking depth (i.e., submerging the 2^nd stage, mouthpiece up, until I hear the airflow) tells me it’s about right and it does not free flow.

However, I notice that my IP falls down to about 130 to 135 psi when the tank drops down to (about) 1500 psi. At this point I notice an increase in the breathing effort in the pool at 9 ft depth and in deeper open water too.

Should that IP fall that much with the MR42T do you think?

Should I set my cracking pressure at the lower IP if that in fact is what it will always be?

And you mentioned in another thread that you would prefer "metal orifices for the Mares 2nds" -- is this still your preference?

Thanks very much again for all your help now and before. I really appreciate it, and Malo.

 

[LeadTurn_SD]

LeadTurn,

... My concern now is about the IP and breathability underwater. I have my IP set to 145 psi with tank at 2400 psi--I use mostly LP steels when possible and dive colder waters. (Mares recommends 142 to 148 psi for 2900 tank press.)

My Abyss breathes quite easily the way it’s set up now. Doing the “field” test in the pool for cracking depth (i.e., submerging the 2^nd stage, mouthpiece up, until I hear the airflow) tells me it’s about right and it does not free flow.

However, I notice that my IP falls down to about 130 to 135 psi when the tank drops down to (about) 1500 psi. At this point I notice an increase in the breathing effort in the pool at 9 ft depth and in deeper open water too.

Should that IP fall that much with the MR42T do you think?

Should I set my cracking pressure at the lower IP if that in fact is what it will always be?

And you mentioned in another thread that you would prefer "metal orifices for the Mares 2nds" -- is this still your preference?

Thanks very much again for all your help now and before. I really appreciate it, and Malo.

Hi rjk75,

1.) I wanted to be positive, so I tested my MR-22 / Abyss before answering your post. I have my IP set at 142 psi. At a tank pressure of 3,000 psi the IP reads a steady 142 psi, very fast lockup and no creep. This is 2 years since I last serviced this particular regulator. At 1,000 psi tank pressure the IP is exactly the same, 142 psi. I did not test, but I would expect the IP to remain stable until VERY low tank pressures.

2.) If you are diving very cold water (< 47 deg F per Mares), Mares recommends using their environmental kit and also lowering the IP to 128 - 132 psi. If you are NOT diving in water that cold, I'd leave the IP alone.

3.) I prefer metal orifices for all 2nd stages, regardless of brand. I feel like I can get a little better "tune" with the metal orifice.

In your case, I think you need to urgently determine why you are seeing a 10 psi drop in IP at lower tank pressures. This should not be happening. I would explore the possibility that there is a problem with the balance chamber, but actually I am really not sure what is happening in your case. Make sure your IP gauge is accurate, but that is probably not the problem. I would talk to your LDS about the IP and have them verify that it is indeed dropping at lower tank pressure, and have them "fix" it. If they cannot, I'd politely but firmly ask for a replacement 1st stage (assuming you bought it from them).

Good luck, and let us know what happens!

Best wishes.

 

[rjk75]

LeadTurn,

Thanks very much again. I just PM'd you with a reply and thought maybe I should post that here, too, for the record re: my IP readings.

I have two IP gauges, both very new. One is 0 to 200 psi and the other is 0 to 300 psi and they're both within a couple of psi of each other's readings. I'll start looking into what's causing that IP to behave that way on Monday.

 

[kebosatu]

Hi Kebo,

This will be a long answer. But I'll try to give you a way to test an Abyss without tools or gauges.

First, some basic information: All good quality 2nd stages that are functioning properly and "tuned" correctly should be able to provide more air flow that the diver would ever need. There will always be a very slight resistance during the first instant of inhalation; this is called the "cracking pressure", the amount of vacuum force that is needed to open the demand valve. Once the valve is open, there should very little additional force needed to open the valve the rest of the way and keep it open for as long as the diver continues inhaling. A well-tuned 2nd stage will seem to provide air so easily that the air flow begins as you think about inhaling. This is a slight exaggeration, but really the work of breathing should be not be any more than breathing normally on the surface, sitting in front of your computer and breathing though your mouth as if a regulator was in it.

Cracking Pressure is measured in inches of water. Lower is better. Most decent 2nd stages are "well tuned" at around 1.0 - 1.5 inches of water. But this varies among different 2nd stages, and there are other factors that effect the overall work of breathing.... and a regulator that has a lower cracking pressure may not necessarily breath better than one with a slightly higher cracking pressure. Finally, how low you can set the cracking pressure in a given 2nd stages is limited by case geometry and the design of the demand valve and seat.

What I noticed with the Mares regs I purchased (online) was that they were tuned very conservatively. They breathed like low end "rental" or "student" regulators; many dive shops will slightly detune rental regulators and regulators used by OW students to prevent them from being as prone to surface freeflows.

I bought 5 sets of Mares regulators online back in 2007, and I suspect they were only tested but not tuned by the dealer.

From the factory, the Mares Abyss regs were set at about 1.8 inches, Protons the same, and Rebel octos were set at 2.0 inches. And in all cases the demand levers were set a little too low. The Mares Abyss should actually be tuned at about 1.3 inches and still be "stable", and the Protons are pretty happy at about 1.2 inches.

I eventually re-tuned the 2nd stages, including setting the demand levers at the proper heights, and it was a difference of night and day in performance.

The only way to know a well-tuned reg from a detuned or poorly tuned reg is to have experienced the difference.

But the difference can be summed up as "Ohhhh..." and "Ahhhhh!!!" .

Be patient with me and take a moment to perform the following exercise:

1.) While sitting at your computer, say the word English word "Ohhhh", and without changing the shaped of your mouth, inhale.

2.) Now do the same thing, but say the English word "Ahhhh!!", and then inhale.

Feel the difference???

That is about how different the inhalation effort feels to me between a 2nd stage that is "cracking" at about 2.0 inches and a 2nd stage that is cracking at around 1.3 inches.

The Mares Abyss should be an "Ahhhh!!" experience, not an "Ohhhh...." experience

The Mares 2nd stages have two adjustments (orifice depth, which effects cracking pressure, and lever height) and they directly effect each other. The adjustments are not difficult, but do require a little extra effort from the technician when the regulator is being serviced. An inexperienced or lazy technician can miss the "sweet spot" with orifice depth and lever height, and end up with a mediocre result and not understand why.

If you buy from a good dealer who sets up and thoroughly tests the regulators, none of what we are discussing will be an issue.

If you end up buying the Mares regs and have further questions, please feel free to send me a PM or post on here. I'm not a "certified Mares technician", but I'm happy to fix their mistakes (just kidding, well, sort of).

Best wishes.

LeadTurn,

Really appreciate your detailed answer.

This is very beneficial to me, now I know there are two configurable parts that I need to --probably-- mention it to the technician, and see is the technician understand about this two things.

Planning to get this item from the master dealer, so this is probably the only place I can hope to get "the best" configuration from. If they don't understand on those two things, then probably I wont get it any better service from other local shops who don't know Mares.

Been browsing some links provided by rjk75 too to get better understanding on some topics we discussed here. And they are very usefull too.

Again, I really appreciate your inputs here. Probably I will provide a report on my first experience with Mares product once I get a chance to test it on the water .

Best regards,
Kebo

 

[kebosatu]

In my last reply I told that I will get mares abyss.. But apparently I changed my mind last minute to get mk25/s600...

Just want to share my experience and my appreciation to LeadTurn_SD who has been very helpful in my first dive gear shopping.

What LeadTurn has shared was absolutely right. I can see that I can use the breathing resistant knob provided to de-tune my Reg on the spot. I can make it harder to breath and even make it free flow, yes I can see that is free flow now after I turn the knob to the max, so I guess it easier to breath now. However when I play around with the knob under the water... I totally CAN'T tell the difference whether this is oohhhhh or aahhhhh -I'm newbie-

But I still think this knob is good to have. Though I might not make this a big deal for my next purchase.

All in all I'm happy with my purchase. Has been using it for 15 dives.

Thanks!

 

[LeadTurn_SD]

You bought a terrific regulator!

There are lots of great regulators from a variety of manufacturers. It is pretty hard to make a bad choice.

Best wishes.