The New Atomic TFX

[rsingler]

Day #6 - TFX and D400 @ specification cracking effort when inverted and more

Last day of diving! My wife renamed Columbia Shallows to "Lobster Flat". OMG, they were everywhere!

I retuned the D400 from 0.6" to 1.0", and the TFX from 0.8" to 1.2".

Both regs were still very pleasant to dive in the standard position. Effectively almost zero inhalation effort to initiate a breath.

Our plan to dive inverted turned out not to be a test, but a necessity. Catching a good photo in a narrow sand trench from fish level (instead of from above) necessitated an inverted position that quickly went past inverted as the current pushed against our legs if we were staring upstream.

You'll be happy to hear that inverted (180°) and looking down was dry with both regs (same as yesterday in Devil's Throat). Inspiratory effort did not change. Expiratory effort became easier. Inverted but looking at a fish across from you while upside down and photographing placed the head of the reg lowest. You could sense moisture entering and would get a little water after four breaths as the "reservoir" in the head filled. Rotating into the reg would dump that water in the mouthpiece. Rotating by arching your back to the standard diving position dumped the water into the exhalation valve. One quickly learned which way to exit the trench.

Similarly, going inverted to photograph and then letting the current push your legs past "vertical head down" to 225° puts the mouthpiece lowest in the water. You could sense moisture coming into the reg and it immediately entered the mouthpiece. Gentle breaths were fine. A big breath would make you cough. After four breaths, enough water accumulated in the roof of your mouth that you had to remove the reg and spit it out, or you had to leave that position.

Lying flat looking up in the water was dry. The diaphragm is lower than the corner of the case that heads into the mouthpiece. If I arched my neck so the TFX diaphragm was parallel to the surface and the mouthpiece was lower, you could feel a mist with each breath. There was no gross water intake.

In short, increasing the cracking effort dried the regs slightly in these unusual positions compared with earlier tests. There seemed to be less mist than when they were tuned hot.

 

[scubadada]

Please summarize your experience for the week.

 

[BoltSnap]

Please summarize your experience for the week.

This was exactly what I was going to write!

We need a report that brings everything thing together with precise final verdict.

(We want value for our money )

 

[rsingler]

I'm typing, @scubadada
Patience, my friend.

 Summary
Without a doubt, the TFX is the best reg I have ever owned. It's cracking effort is light (even when tuned to spec), due to the diaphragm's position low in the water. Its exhalation effort is equal to all my other regs except the D420, which is better than any reg I've ever seen, but only in the standard diving position. Atomic's use of a larger valve, multiple gas exit pathways and shaped exhaust wings has overcome the increased resistance of the D400's high collared diaphragm retainer and small cover holes.

Leaving the reg deliberately diaphragm down, hanging from a D-ring on giant stride, with Venturi turned to Min (but still hot-tuned), the reg freeflowed once in 10 jumps.

Tuning hot was not the freeflow problem I expected. Rolling the reg to one side easily flooded it and it never freeflowed in current when dangling.

The reg turned out to be very sturdy despite deliberate abuse, belying its lightweight flexible purge cover and flexible exhaust wings.

In testing when hot-tuned, the reg did not exceed 1.7" of cracking effort (about like a poorly tuned octopus) even if I deliberately dropped the IP to 20 psi!!! The balance of this regulator is unbelievable. I have never tested a valve with this degree of IP tolerance. When I get home, I'll find out the upper limit of IP before it freeflows.

So here is the basic tradeoff between your favorite barrel design, end-balanced second stage, and a center-balanced, low diaphragm front exhaust like the TFX:
** With a barrel design, case geometry fault is the Achilles heel. You can't look up at a shrimp under a ledge without inspiratory effort really rising. Upside down, most breathe a little wet because the exhaust valve is near-vertical.
** With a D400/TFX style second, the Achilles heel is ONLY diving upside down, where it displays almost none, to moderate moisture. The absence of a cracking effort adjustment knob turned out to be a non-issue for boat diving. For surge'y beach entries, it may or may not be a problem as a dangling octo.
** Service is a slam dunk, and the only particular is ensuring proper lever height. It should be easily possible for a diver with a small face spanner to tune the reg to a different cracking effort without the dangerous consequence of lever drop, distinctly unlike a barrel design.

I grew up with the D400. I grew addicted to easy breathing regs. I suffered with the service challenges. This reg is all that my favorite was, and more. No corrosion, easy service, light breathing and Atomic has solved the exhalation effort challenge of the D-series design.

The only thing I await is an ANSTI loop to confirm or refute my new prejudices.

 

[Yellowdog]

So the TFX breaths well underwater?

 

[Joneill]

I

Day #6 - TFX and D400 @ specification cracking effort when inverted and more

Last day of diving! My wife renamed Columbia Shallows to "Lobster Flat". OMG, they were everywhere!

I retuned the D400 from 0.6" to 1.0", and the TFX from 0.8" to 1.2".

Both regs were still very pleasant to dive in the standard position. Effectively almost zero inhalation effort to initiate a breath.

Our plan to dive inverted turned out not to be a test, but a necessity. Catching a good photo in a narrow sand trench from fish level (instead of from above) necessitated an inverted position that quickly went past inverted as the current pushed against our legs if we were staring upstream.

You'll be happy to hear that inverted (180°) and looking down was dry with both regs (same as yesterday in Devil's Throat). Inspiratory effort did not change. Expiratory effort became easier. Inverted but looking at a fish across from you while upside down and photographing placed the head of the reg lowest. You could sense moisture entering and would get a little water after four breaths as the "reservoir" in the head filled. Rotating into the reg would dump that water in the mouthpiece. Rotating by arching your back to the standard diving position dumped the water into the exhalation valve. One quickly learned which way to exit the trench.

Similarly, going inverted to photograph and then letting the current push your legs past "vertical head down" to 225° puts the mouthpiece lowest in the water. You could sense moisture coming into the reg and it immediately entered the mouthpiece. Gentle breaths were fine. A big breath would make you cough. After four breaths, enough water accumulated in the roof of your mouth that you had to remove the reg and spit it out, or you had to leave that position.

Lying flat looking up in the water was dry. The diaphragm is lower than the corner of the case that heads into the mouthpiece. I f I arched my neck so the TFX diaphragm was parallel to the surface and the mouthpiece was lower, you could feel a mist with each breath. There was no gross water intake.

In short, increasing the cracking effort dried the regs slightly in these unusual positions compared with earlier tests. There seemed to be less mist than when they were tuned hot.

What do you see as the benefit to hot tuning your TFX to 0.8? Is it ever easier breathing? I loved how my TFX breathed on it's first outing back in late September but I dove it as received from Atomic. To me, it still was noticeably better than my T3 - not earth shattering, but just super smooth!

 

[rsingler]

Yes, I hot tune for truly effortless breathing. It comes at a cost - slightly more likely to freeflow, but only when the reg is not in your mouth and not flooded. If I had two TFX, I would tune the octo to 1.2, although I have to admit, even my hot-tuned reg never freeflowed during dives in current when it was dangling from my D-ring. The  only time it seemed to play a role was at the end of a dive, with a full wing, as I rested on my back awaiting boat pickup. I could hear it occasionally burble as it rested on the front of my bcd bobbing in and out of the water mouthpiece up. I can find no real downside to hot tuning with this design. As I noted above, it freeflowed only once in ten jumps dangling from a D-ring, and I had deliberately twisted the angled adapter each time so that the diaphragm faced directly at the water for the jump.

I really enjoy the effortlessness of a hot tuned center-balanced valve.

I realize in reading your comment that in my summary, I left out the key standout feature of the TFX compared to every other reg I own. You're right - it's truly the smoothest air delivery of any reg I've ever tuned in the shop.

 

[rsingler]

As noted, I was deliberately rough with the reg, just to see if there was anything fragile about it. This reg had already been disassembled and reassembled half a dozen times before the trip. Despite a week of mistreatment during diving (I'll get a new purge cover and decorative collar when they become available) she really stood up to the abuse:

And without the harsh glare of the flash, she still looks almost new.

 

[Yellowdog]

Inhalation
Inhalation was a delight from both regs. With the low diaphragm both valves are preloaded by ambient pressure and are ready to open, held back by positive pressure in the case (because the diaphragm is lower measured from your throat than the cracking effort). Thus, all you have to do to breathe is inhale and the air flows. (To prove to yourself that the valve is always ready to open in the standard diving position, just take your mouth off the mouthpiece - it freeflows like crazy as soon as that positive pressure maintained by your mouth seal is removed.)

This gets my attention. Does it stop freeflow if you turn sideways and flood? How do you orally inflate your SMB?

 

[rsingler]

This gets my attention. Does it stop freeflow if you turn sideways and flood? How do you orally inflate your SMB?

Like all other regs, a freeflow stops when you turn the reg mouthpiece down. The TFX is different in how you flood it only due to the low diaphragm. See this post for discussion of flooding:
The New Atomic TFX
Oral SMB inflation is same as with all others: inhale, then turn mouthpiece down while you blow into the SMB inflator tube.

As I peruse the thread, I think @Joneill had the best summary of how this reg performs [emphasis mine]:

All in all, I love the reg - it is definitely the smoothest breathing regulator I’ve ever breathed from. It feels completely linear: you can just lightly sip air or take a deep breath or anything in between. It will deliver exactly what you want - as light or deep as you breathe.

I’ve always loved my T3 but, by comparison, the T3 feels less linear - almost like you can sip lightly but once you pass a certain level of inhalation, it gives you a higher flow - almost like there are 2 “speeds”. The TFX just gives you whatever you pull from it.

That's it in a nutshell!
Damn, I love this reg!