Modified Voit Trieste with FX Cans

[macado]

So with the upcoming release of the Argonaut Kraken, I started thinking about the Voit Trieste that I've had sitting in my parts bin for almost 2 years. I had intended to get around to rebuilding it but things get in the way. I figured I would build my own "Pegasus" or as close to it as I could get.

If you guys remember my last thread where I rebuilt a Voit Trieste, I kept that one mostly stock with the original cans but made an improved diaphragm. Unfortunately that regulator was rebuilt for a friend and has not really seen any diving since I rebuilt it.

Probably two years ago, I had purchased a machined HP adapter from Herman and an upgraded balance chamber with back-up o-ring from Greg. I didn't realize I had them until I started rebuilding this regulator.

Thanks to Rob at the Scuba Museum, I bought some modified FX cans, gray hoses, gray diaphragm, gray Voit mouthpiece from and some miscellaneous parts from Bryan at VHD (new HP aqualung poppet, etc), I finally had all the parts to complete my little project.

Like the Voit MR-12, I find working on the Trieste to be very easy. Once I thoroughly cleaned the parts, I had this up and running in no time, installed new duro 90 o-rings, new Aqualung HP poppet with upgraded balance chamber and conshelf pin cut to 0.630". The 2nd stage is the original Trieste one, I haven't made any modifications to that yet. Adjusted the IP to ~135psi at 3000psi and she's holding steady with no creep and very responsive.

Like the other Voit Trieste I rebuilt, this is an early model (serial 00860). On the left side where the optional reserve would go I attached the machined HP adapter so I could use an SPG. On the right side there is one LP port that I attached a 3 way LP splitter so I can run modern accessories and my drysuit.

She's a beauty! She'll be pool tested this weekend or I may forgo that step and go right into cold water sea trials. She'll have to suffice until I cough up the dough to purchase an Argonaut

[antique diver]

That looks good, and ought to be a nice performer with the larger case and diaphragm. Let us know how your dive goes.

I'd like to try the FX cans out with a Titan 1st stage if I could find a Trieste 2nd stage and lever. I spent a couple of challenging years monkeying with my Trieste to get it breathing the way I wanted in the original cans, and I'm satisfied with that except the hoses sort of bother me because of he narrow angle behind my head. I don't want to tear my Trieste apart to make the new reg.

[macado]

So I got to play with this in the pool for a little bit tonight. It breathes *okay* but I'm noticing slight issue that I'm not sure how to troubleshoot. I need to really spend a bit more time as I only had 5 minutes to play since I was teaching a class

When I inhale it seems to skip breath or pause when taking long inhales. I'm not quite sure how to describe it. On surface it breathes smooth, exhales fine but definitely seems to be a bit more resistance than expected underwater.

IP is stable and set at 135psi, seems to rebound very quickly on inhalation. 2nd stage air opening is pointed down horn of can (slightly to the side I think depending on how it's lined up).

If

Any ideas?

[Creed]

When I inhale it seems to skip breath or pause when taking long inhales. I'm not quite sure how to describe it.

Do you mean that the air cuts off for a moment?
I would first isolate the problem. See if it happens on other tanks to start.
Second, if you have a submersible IP gauge, see if the IP fluctuates when it happens. If the IP bottoms out, I'd think it would have to be the first stage or tank valve. If not, I would make sure the channel that feeds the 2nd stage is not partially blocked. After that, look at the 2nd stage assembly for blockage or burrs that may catch.
Just my $.02.

[macado]

When I inhale it seems to skip breath or pause when taking long inhales. I'm not quite sure how to describe it.

Do you mean that the air cuts off for a moment?
I would first isolate the problem. See if it happens on other tanks to start.
Second, if you have a submersible IP gauge, see if the IP fluctuates when it happens. If the IP bottoms out, I'd think it would have to be the first stage or tank valve. If not, I would make sure the channel that feeds the 2nd stage is not partially blocked. After that, look at the 2nd stage assembly for blockage or burrs that may catch.
Just my $.02.

Thanks Creed. Air doesn't cut off but it seems not too be as smooth as it should if that makes sense. Tank/tank valves seem to be fine as I was breathing off other regulators with this tank. I don't have a submersible IP gauge but will do a bit more testing on this. I'll have to check again but IP is very quick to recover back to 135psi on surface and doesnt bottom out when on heavy breathing.

I'm in the pool again this weekend so I'm going to do a bit more testing and tweaking with the 2nd stage.

I would love to get my hands on one of those other 2nd stages that were made for the Pegasus but I know that they are few and far between