Our performance test of 18 top regulators continues. Last month we tested 10 currently-available models of regulator (selected at our request by their manufacturers) in the laboratory, and in the sea.
So how did the 8 regulators in our second (more expensive) batch - the Spiro Pioneer XP, Apeks TX50, Sherwood Maximus, Mares MR12 Voltrex, Poseidon Triton 2000, Dacor Extreme Plus, Scubapro Mk20/G250 and Mares MR22 Abyss - perform under the same test conditions? This is what we discovered.
Our test divers liked the idea of the Spiro Pioneer XP (£216) with its modern oil-sealed piston-with-diaphragm first stage. It seems ideal for British conditions. However, we found that its tall turret has a tendency to knock you on the back of the head unless mounted on the tank 'head down' - an arrangement which can lead to some routing problems with the hoses and with some tanks may not be possible at all. It has 2 hp ports and 4 mp ports.
The XP second stage is a classic design, if a little large, and we all thought that the exhaust deflector was very good. Because the port for the primary second stage is oversized, Aqua-Lung (UK) supplied it with a Spiro Octopus. This meant that our test divers had to swap them over during the test.
In the water, George Brown thought it had "a very average breathing performance". On the other hand, Joanne thought it was very comfortable and good to breathe from.
Tamara thought it "a very tight breathe. I kept thinking I was running out of air. The Comfobite mouthpiece isn't exactly comfy."
George Buxton was disappointed. He suggested we might have been sent an example which hadn't been set up properly.
On the ANSTI machine, it worked well, performing to the required criteria down to a simulated sea water depth of 59.6m. The pressure/volume diagram obtained at this point revealed a well-shaped curve with little flutter on inhalation.
The Apeks TX50 (£232) is made in Britain and has become a favourite with technical divers. It was the forerunner of this valve, the T50D, that Diver used for its first practical deep-water test in 1993.
We all thought that the dry design of the environmentally-sealed TX50 first stage was brilliant. We liked the way the turret could be used 'right way up' on the tank. We thought it was only spoiled by its shrink-wrap style hose protectors. The second stage looked very similar to previous top-of-the-range Apeks models, with both a breathing resistance (BR) control (or de-tuning) knob and an easy-to-operate venturi plus or minus switch. In the water, George Brown found it to be "a very good breather indeed".
"The switches for the BR control and the venturi both worked very well. I had it set up for optimum performance at 40m."
Joanne "really liked this valve, even its exhaust flow routing. It gave me everything I wanted."
Tamara said it gave a very pleasant breathe. The second stage was lightweight, though not small. "It was nice to have in the mouth."
George Buxton said it was excellent. It gave a smooth performance - possibly the best. "At 40m I used it on the maximum setting of the venturi and BR controls. Then I switched to the minimum settings. Although I felt a definite restriction, it still managed to deliver all the air I wanted."
What did the ANSTI machine tell us about this highly regarded regulator? Like its cheaper sibling, the TX40, it beat the machine. At 80m-plus, its pressure/volume diagram curve was hardly dipping below the central axis of the graph. The inhalation pressure at this point (at 1.31 kPa) was only half the acceptable limit.
The Sherwood Maximus (£247) was unusual in that its second stage was joined to its extra long mp hose by a pivoting connection. We decided that the designers intended the user to pass the hose under the right arm rather than the more usual routing over the shoulder.
The piston-type first stage had 5 mp ports but only one hp port. The radial layout of these ports sometimes made for awkward hose routing. More seriously, we found that this valve did not marry well with many tank valves - mainly those which were A-clamp conversions with DIN inserts.
The Sherwood dry-bleed system left a permanent trail of small bubbles in the water, which sometimes made us feel as if the tank O-ring could blow at any moment.
We thought that the second stage was nicely machined, with an excellent BR adjustment knob. It was very strongly made. Its very deep mouthpiece was not noticed by all to be different from any other in the water. We thought that it would have made a better octopus rig than a primary second stage, but the purge button was too well concealed for use in an emergency by someone who was not familiar with this regulator.
George Brown thought that the inhalation required some pull even though it was nice and dry. "I didn't like the drag factor." Nor did he like the way the hose needed to come under the arm, feeling that it might catch on other gear.
Joanne said: "The exhaust bubbles obscured my view!"
Tamara liked the good hose length and swivel connection. She found it quite difficult to achieve her required air flow by means of the de-tuning knob. She found it extremely hard to operate the purge button under water. The exhaust bubbles seemed very loud because they passed by her ears. "The mouthpiece was such that I was sometimes on the verge of gagging. It's a tonsil toucher!"
George Buxton thought that it gave him a really restricted breathe. "The adjustment knob was hard to position precisely. Even with it free-flowing, if you were afraid that you could really over-breathe it and it could cause problems."
The ANSTI machine gave a pressure/volume diagram which was nicely symmetrical, indicating an even breathe, down to the failure point at 47.2m.
The Mares MR12 Voltrex (£255) is a regulator which did very well in our previous (1994) deep-water test.
We thought that the radial layout of the ports around the diaphragm-style MR12 first stage was not good in that it was likely to cause stress in the routing of at least one of the hoses. There are five mp ports but only one hp port, a ratio which seemed inappropriate.
The second stage is almost identical to that of the Mares MR22 Abyss (see below). Because the primary second stage is designed to connect to an oversized mp port and a wide hose for "dynamic flow control", we were sent a Nikos octopus rig to try with it.
We liked all the Mares second stages because they were small and compact. With the exception of the all-plastic Nikos Octopus, they all used a lot of metal in their construction - which promises good resistance to cold-water problems. They looked nice, and although they appeared to be very deep from mouthpiece to purge button, this was an illusion caused by the small diameter of the unit.
We liked the idea of the by-pass tube which was effective in stopping any tendency for the valve to free-flow, and thus neatly did away with any need for a manual venturi control.
This regulator was one of our favourites. George Brown thought it good to breathe from. He felt it had a good all-round performance. "I liked it a lot."
Joanne thought it was "nice".
Tamara said it was very nice and lightweight. "It gave very, very good breathing. Even at the end of the dive when the tank was almost empty, it felt much better than another regulator which was fitted to a full tank."
George Buxton said that he found that it gave a perfect and steady delivery. It was very smooth. "There's not a lot you can say when something's OK!"
The ANSTI machine plotted a textbook curve for the MR12 Voltrex's pressure/volume diagram. This regulator finally reached our limit for inhalation pressure at a seawater depth of 61.5m. Although it may not have gone as deep as some of the other models we tried, it behaved in a most gentlemanly manner!
Poseidon regulators have had a dedicated following for many years. We tried their latest offering, the Poseidon Triton 2000 (£281).
It's an avante garde design which, in the true tradition of these Swedish demand valves, can be used with its mp hose routed from either the left or the right. In this case, the unique second stage is fitted with a central swivel to the connection with its hose.
The purge button is disguised into the top horizontal portion of the second stage, but we all thought that, in a panic situation, a diver unfamiliar with this unusual positioning would merely try to press the Poseidon badge at the front. Also, the hose normally sits on the bottom (with the Poseidon badge the right way up), but our test divers opted to use it the other way up. It seemed to function equally well, and they found it more comfortable.
The first stage is a traditional Poseidon diaphragm design with slightly different inter-stage pressure. Like other Poseidons, it has a built-in DIN fitting, plus an A-clamp conversion. We experienced difficulty fitting a computer transmitter unit (Air X, Monitor 3, Genius) because the ports were so close together. George Brown liked the second-stage swivel system. He also found it very comfortable in the mouth. However, he felt that the regulator fluttered most of the time, at all depths. This gave him the sensation of a disturbed air flow in the mouth.
Joanne said she really felt she had to suck hard. It fluttered. The delivery was irregular. "I didn't make me feel confident. It seemed to let in water too."
Tamara thought it had a very noisy action. It was slightly wet at all times. She felt that the breathing quality was "less than average". But she "liked the purge button position, despite earlier misgivings."
George Buxton said: "Used right way up, the air appeared to be directed at my lower teeth, which proved uncomfortable. Breathing was neither smooth nor consistent. It seemed to come in gulps. It tended to flutter with certain positions of the head. I liked the way that the exhaust bubbles were routed clear of my head, but I found the purge button particularly difficult to reach because it was located directly beneath the nose pocket of my mask."
The ANSTI machine test revealed a regulator which could meet the criteria down to 63.7m, but whose pressure/volume diagram showed violent fluctuations of the inhalation pressure.
The Dacor Extreme Plus (£299), with its modular construction, is a very unusual-looking regulator.
We thought that its first stage was an 'amazing bit of plumbing'. It is extremely heavy and looks like a set of kitchen mixer taps. It appears to offer a huge amount of flexibility regarding the possible layout of the hoses, with four-way tilts to two of the mp ports and two-way tilts to two others. There's only one hp port. Are servicing costs high? It must be full of O-rings.
The hose fittings look expensive too, should you need to replace a hose.
The second stage seems to be almost identical to that of the Dacor Quantum (tested last month). It suffered the same strengths and weaknesses. In addition, it has a breathing resistance knob, which needs five turns to cover its range before it clicks out-of-gear to avoid overtightening. It also has a venturi switch which is almost impossible to see in low light and is made of the flimsiest of plastic.
We didn't think that the second stage lived up to the over-engineered look of the first stage. In the water, George Brown thought that this regulator was an average performer. The venturi switch seemed to make no appreciable difference. The purge button worked fine under water although it is disguised in the rubber shroud which doubles as the exhaust deflector. Joanne said, "I liked the look of it, but it was not so nice to breathe from".
Tamara thought it average, neither particularly good nor bad.
George Buxton said that it fluttered a bit at the surface but otherwise had a very nice breathe, very dry, and very smooth. He found the BR control offered a broad range of settings, from very restricted to free-flow, and was very precise. On the other hand, the venturi switch was small and ineffective.
During our ANSTI machine test, the air supply from this regulator fluttered dramatically, just as it had with the Dacor Quantum. This made it difficult to establish the exact point at which the inhalation pressure and the work of breathing reach the acceptable limits. In the end, we settled on a maximum working depth of 49.7m.
The Scubapro Mk20/G250 (£300) is a new regulator which replaces some good old favourites from this manufacturer. We were really looking forward to trying it. When we did so, it provided our test divers with experiences which uncannily reflected the results from our ANSTI machine.
The Mk20 first stage is a piston design with a turret, which we again found best to rig inverted on the tank. It has two hp ports and four mp ports with good hose protectors at the first-stage end. Because the mp ports are arranged closely together, hose routing was not a problem - although the turret's small diameter causes the hoses to feed off at awkward angles.
The G250 second stage had a nice, if rather conventional, appearance. It has a flow adjuster and a venturi switch. The ladies thought the knobs too small. The plus/minus switch for the venturi adjustment was felt to be very flimsy too. In the water, George Brown felt it was comfortable to hold in the mouth, and it delivered copious amounts of air. "I'd recommend it!"
Joanne said that she hadn't realised how different regulators could be, and thought the Mk20/G250 to be one of the better ones.
However, with Tamara it free-flowed on descent. It took a lot of in-water adjustment of the BR control knob, and the venturi switch markings proved impossible for her to decipher even in bright light and clear water. She also felt it was difficult to hold the mouthpiece straight in her mouth.
George Buxton felt that the air delivery was no problem whatsoever. The air felt comfortable but the venturi switch seemed to have little or no effect.
I, personally, had problems with this regulator free-flowing when I took it out of my mouth. On the dive in question, I needed to make a 70-minute ascent and would have preferred to breathe down each of my twin cylinders evenly. However, every time I took the G250 out of my mouth it free-flowed horribly, so I was forced to use it until its tank was virtually empty. Only then could I switch to an alternative tank and regulator. This effect would obviously be quite disconcerting if you were concerned about having enough air for the dive.
During the ANSTI machine test, the Mk20/G250 free-flowed as it was put under increasing pressure; but it afforded enormous quantities of air and didn't reach its limit until it had exceeded a depth of 72m. At this depth, the pressure/volume graph indicated a certain amount of resistance at the beginning of each inhalation and then a swift supply of air.
The Mares MR22 Abyss (£325) came with its diaphragm first stage fitted with one Abyss second stage and one Voltrex second stage. Our test divers tried both.
We thought that the MR22 had the best configuration of its four mp and two hp ports of any of the regulators we tested. It's a lovely bit of kit, nicely machined with great ergonomics. It's also incredibly heavy.
The primary second stage (Abyss) is on the end of an extra broad bore "dynamic flow control" hose with a unique port connection. It's made almost entirely of metal, with the typical Mares venturi by-pass tube, but its compact design means that it isn't too heavy in the mouth. It comes with good hose protectors at both ends of the mp hose. The compact exhaust T has been improved over earlier models which allowed water to flow directly through, if there was a current, which might have allowed the exhaust valve to lift and let water in the mouthpiece. It's an improvement which works.
George Brown thought it was a "great all-round performer", but he found the large-bore mp hose to be rather stiff and unwilling to bend. This meant that a good bite was needed to retain the second stage in the mouth.
Joanne thought it was excellent. "Everything was good. It was comfortable. There were no problems."
Tamara said it was a light breather. So light, in fact, that she felt it was too easy for her taste, almost shoving the air down her throat.
George Buxton reported that he found it a nice smooth performer, devoid of faults.
No-one was able to discern any difference in performance between the Abyss and Voltrex second stages.
The ANSTI machine revealed this regulator to be capable of meeting the criteria to 57m. At this depth there was a little resistance to inhalation in the form of the tiniest amount of flutter.
So what did we learn from a week of diving with 18 assorted regulators? Firstly, they were all adequate in their ability to supply two divers (one via an octopus rig) with air at 40m, but some were better than others. They've all certainly improved since we first started testing regulators back in 1989.
George Brown got on with his job, diving professionally, when he returned to Scotland. He later observed that it was at that point he realised how useless was the performance of his own regulator which he'd used for many years!
Tamara, always using her own regulator in the past, never realised they differed so much. George Buxton said he had a very open mind about brand names now, but certainly felt it was not worth paying extra for knobs you probably would never use.
Did we have a favourite regulator from the 18 tested? The Mares MR22 Abyss is undeniably a gorgeous bit of kit. Any diver would be proud to own one - but then again it was the most expensive regulator in our review. The Oceanic Alpha was among the cheapest regulators we tried - yet, although modest in appearance, it had a first division performance. The Spiro Supra makes a good standard by which others can be judged, as does the Scubapro Mk20/R190.
The Apeks TX40 is sensibly priced, gave an outstanding performance at any depth, and we liked both the dry design of the environmental-sealed first stage and the simplicity of its second. There were several other excellent all-rounders - all of them good enough for normal leisure diving.
Probably the most important thing I discovered, as dive organiser, is that, assuming your own regulator second stage hose passes over your right shoulder, if you want to be able to offer your octopus rig to another diver, and for that diver to use it in any manner they wish, you may find it better to have it rigged on your left side, over your left shoulder. This enables the recipient diver to face you, or swim by your side, without the problem of hoses taking awkward routes. You also ought to have an mp hose on the octopus rig of sufficient length to avoid dramas.
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