New Sherwood Magnums?

[reefrat]

Has anyone tried the new Sherwood Magnums??
I've always had a soft spot for these since I enjoyed using the model II's in my Open Water class in '91, but they got canned in every comparative regulator tests since then so (being a reg *****) I looked elsewhere all these years!
Apparently they have sorted out the (apparent) wet breathing and WOB issues in the latest model- anyone got an opinion on the new ones?

 

[FM1520]

Check out scuba gear reports, they tested and ranked the Magnum pretty high. Link is below.


TOP STORY / Budget Regs

 

[reefrat]

Yep, saw that one and another review said much the same.
If I hadn't just ordered some HOG D1 second stages I might have gone with the Magnum.

I remember the Magnum II of the late 80's seemed to some features different from other regs at the time- including a roller on the end of the demand valve lever. When I was a typical nervous student it breathed smoothly enough to inspire confidence.

The first stage looks bigger on the new regs and I suspect that it has a greater internal volume of intermediate pressure to improve gas flow to the second stage.
On the second stage the differences appear to be a controllable venturi with an apparently larger exhaust valve and demand lever diaphragm.

If the performance of the Magnum is really as good as the reviews say (without sacrificing the famous durability of these regs) then we will probably be seeing these all over place in a few years, just like the older ones!

Cheers

 

[Hatul]

I wonder if these make the bubbles from the first stage like the old ones?

 

[reefrat]

"I wonder if these make the bubbles from the first stage like the old ones? "

Scuba Diving.com, in their 2011 reg tests conclusion said "The reg’s first stage features Sherwood’s patented Dry Air Bleed System, which keeps the interior clean and dry, and provides stable output pressure".
This sounds like the same system as the older first stages.
However, they also describe the first stage as a "balanced diaphragm", which I'm sure is a typo!

The Sherwood site doesn't mention the "dry air bleed system" but instead says:
• Balanced- piston delivers ample air volume at stable intermediate pressure to the second stage over a wide range of supply pressures.
• Spring chamber is environmentally sealed to maintain cleanliness reducing the effects of corrosion and contamination. This contributes to uniform high performance as the regulator is used.
• Dry-sealed first stage uses no liquids or gels that can leak or add to service costs.

It seems the new first stage is most likely a re-design of the original and I wouldn't be surprised if it uses the same service kit but with an improved internal design to increase gas flow.

Short answer- it will probably still emit that little stream of bubbles that add to about one breath worth of gas in an average dive (or so I remember being told)!

 

[davetowz]

13-25 CC per minute is the usual spec for testing the dry bleed system. About .02 cu ft in a 45 min dive.

 

[reefrat]

Have set up my new 2011 Sherwood Magnum with an also new Brut Octopus.

my first impressions:
The primary hose on the Magnum seems more flexible than any other factory rubber model I've used and I haven't bothered to put a Miflex hose on yet.
The Seacure II mouthpiece fits perfectly and the factory mouthpieces feel very short to me- in fact with the Brut on a necklace there is barely enough room left on the mouthpiece to get a bite on due to the necklace taking up some of the space- so a new mouthpiece will be going on there too!

The quality of the second stage construction looks good on the outside- I haven't checked inside yet because opening the front cover is apparently something on a "trained technician" should attempt (see my thread over on the Sherwood Manufacturers forum).

The first stage also looks to be good quality and is the Genesis GR450 unit re-badged, no continuous stream of bubbles is emitted as per the earlier Sherwood dry air bleed units.

I put it all together on a 65 with an Oxycheq Mach V and went for a pool checkout dive:

Observations:
The Brut octopus free flowed like crazy, every time I entered or submerged rapidly. You need to keep a thumb over the mouthpiece until it is submerged and maybe it should have had some venturi down-tuning lever as well. For a secondary it breathes reasonably well and I'm happy with it generally.

The magnum breathes great in the horizontal and head down positions, the cracking pressure is very light and it delivers gas very smoothly whether sipping slowly or sucking hard. Tt is however a little positional and there is a noticeable increase in inhalation resistance in the head up and face up positions. Nothing dramatic but very noticeable compared to my Atomic B2 which breathes almost exactly the same regardless of position! It's not a problem and I'm not complaining about it, in fact overall I'm happy with the WOB, at least in the shallows.
The exhaust tee is very short and bubbles pass the front of the mask in the slightest face up position but seem about average for interference and noise in the horizontal position- once again no complaints!

Overall, seems like a good quality simple rig that breathes well in typical diving positions and I'm looking forward to Cozumel in about a week.