D420! How about that?

[axxel57]

No, the X650 had already the classic exhaust valve design.
I think the problem with the concentric exhaust valve of the Ds was that the space between the exhaust valve and the diaphragm cover was very limited and 'restricted' the exhaled air flow a bit.
Before the CE Standards and the ANSTI Machines that didn't play a role as it did not in practice, but since cracking effort, inhaling effort, and on the other hand the exhaling effort are valued same ( which for me doesn't make sense) for the WOB, the exhaling values could spoil the overall result.
That's how I understood that guy....

 

[axxel57]

Now I found the file that the SP guy published here to illustrate their problem with the exhaling effort values.....

 

[scrane]

I happen to have a d400 paired with a 108 safe second. On my setup, on dry land, the exhalation force on the d400 is indeed heavier subjectively. The 108 exhale is virtually effortless, while the d400 has a shelf and some flutter. I have been inside the 108 and have cleaned it thoroughly, while the d400 has not been cracked open by me. So there may very well be extenuating circumstances. The d400 does have some dead space on inhale before the diaphragm hits the lever.

 

[buddhasummer]

Had my D420 out again today, it really is a very nice breather. Primary it will remain for sure. There is a noticeable difference in performance between the 420 and the 250 and I do mean noticeable, so much so I put my G250 on a gauge as thought something was wrong, nothing wrong, cracking 1-1.1".

 

[buddhasummer]

It "seems" to breathe even better at depth, am contemplating an 50m dive with it as am interested in how it performs at greater depths. I know I know.

 

[lexvil]

It "seems" to breathe even better at depth, am contemplating an 50m dive with it as am interested in how it performs at greater depths. I know I know.

Someone else here is planing a 150 foot dive this weekend, not me sadly.

 

[buddhasummer]

Someone else here is planing a 150 foot dive this weekend, not me sadly.

Will they be using a D420?

 

[lexvil]

Will they be using a D420?

That’s the word

 

[buddhasummer]

That’s the word

Cool, then we'll have two points of reference. "Might" drop to 60 for sh.ts and giggles.

 

[rhwestfall]

Depth irrelevant, I wish I could dive....