Saturday, 30 June 2012



I recently received an Apeks XTX 40 Regulator for review. Straight away on opening the box I knew I would have a lot to write about, even though this is regulator from near the bottom end of the Apeks range. The XTX 40 is packed so full of features I asked myself whether a diver would really need to pay more for a higher range regulator. I have now completed a number of dives using the regulator and after a bit of background,  I will tell you how I got along.
Firstly the background – Regulators are perhaps the piece of dive kit that you will become most attached too. Its the open circuit divers lifeline and certainly through my diving career I have favoured certain brands. Over the years I have owned Aqualung, U.S. Divers, Scubapro and Apeks regulators as well as trying out many other types. Some brands were perhaps too expensive for my budget or just contained features that I thought were strange or useless. Every open circuit diver requires to learn a little about the differences between regulator types to make the right decision for themselves and I will highlight points of interest within this feature.
My current TX 40 which is around 20 years old and is now being retired sports a very similar first stage which looks almost identical to the current model but the second stage has evolved considerably in the current model.  
How I Got on with the XTX 40
In the tests I dived the XTX 40 between 0 and 40 metres deep and used a variety of gasses. The XTX 40 was also on a deco stage when conducting deeper dives up to 60 metres. Straight out of the box the XTX 40 can be used with nitrox mixes of up to 40%.
First Stage
The First Stage supplied with my regulator was the XTX 50 (DST) This means that it is a dry sealed system with a swivel turret. What this offers the UK diver and more importantly the Scottish diver is excellent cold water diving performance. The C.E.N. standard defines cold water as 10ºC (50ºF) or lower. Therefore to dive in Scotland at any time other than the summer months we require a regulator that performs considerably better than that benchmark. Most of my dives were carried out in water ranging between 4 to 8 ºC.
Firstly this is a dry sealed balanced diaphragm style first stage and this is my preferred type. It is completely sealed therefore its internal mechanisms will not be affected by salt water corrosion or any other external contaminants, offering the diver complete environmental protection. This will result in less post dive maintenance and lower servicing costs. Keeping cold water away from first stage moving parts also helps this regulator perform well in cold water. Other styles of regulator may use a balanced piston design, which does let salt water enter part of the first stage. This choice of design type is something that any diver wishing to purchase a regulator should consider before committing to buy. Both types work very well however, The purchaser requires to decide what suits their diving needs best.
What balanced means in relation to the First Stage is that no matter what the cylinder pressure is, the breathing resistance will always remain the same. Unbalanced first stages become more difficult to breath from as the cylinder pressure drops.
The XTX 40 first stage has 4 MP ports and 2 HP ports. The MP ports are located on the swivel part of the turret. This allows for hose routing  to suit all configurations of dive kit. All Apeks First Stages are available in either A Clamp or Din Fittings. I opted for the DIN fitting and note that the ring for unscrewing the reg from the cylinder has been redesigned and is now more user friendly, especially for cold hands.
At the end of this review I will quote the current RRP. And prices you can expect to pay in Dive Stores for this Reg. One thing to watch out for though, is that if you see a price that is far lower, the first Stage supplied may be the XTX 40 (DS4). This First Stage does not have the Swivel operation and is Apeks entry level First Stage.
Negative points? well there are not any really and certainly not with the XTX 40 reg supplied to me. Historically what I have found with my TX 40 and TX 50 is that the very top of the First Stage where the swivel is located. The “o” ring here because of the movement is susceptible to wear and over time small bubbles will be seen to escape from here. This certainly has not happened with the new reg and Apeks may have looked at this in the intervening years as part of the internal development of the first stage. However an annual service scheme will prevent this from happening.
More expensive First Stages such as the XTX 200 are formed from a solid block of brass and hence have no external moving parts.

Second Stage (2nd)
This is where I noticed the main technical changes in the XTX 40 as opposed to my old TX 40. Firstly the exterior of the 2nd stage feels solid with a 2 shot plastic front cover. Durability should be second to none and I expect to see lots of hard wearing Apeks regulators looking as good as new in 5 years time. Whilst externally the 2nd stage looks to be plastic. The bulk of the internals are metal. This is advantageous as it uses the heat from the divers expired breath to heat the breathing gas. In the manual this is known as the Thermo Dynamic Heat Exchanger.
The 2nd stage is pneumatically balanced which ensures breathing resistance is minimal
One of the special extras of the XTX 40  2nd stage is that exhaust tees are user exchangeable. The XTX 40 is supplied with the standard compact exhaust Tee. This will suit most divers however for underwater photographers like me the option of purchasing the larger exhaust tee is a must as this stops bubble interference to the bottom of the camera housing. Unfortunately unlike the XTX 200 this large exhaust tee is not included and has to be purchased separately for the XTX 40. Another special feature which I do not have and can’t really comment on is a New Optional Extra Hose Swivel connection. What I can say though is that it is great that Apeks are thinking of the different products to meet the requirements of specific divers.
The XTX 40 also features a Venturi control (also known as a pre dive switch). This control alters the air flow in the 2nd stage. The switch in the minus position disrupts the airflow and is used when entering the water to prevent a free flow. Once in the water though the control can be moved towards the + sign and a baffle is removed directing air into the mouth creating a venturi effect. This is not just a purely on/off switch; it can be used to find the divers preferred breathing resistance.
The XTX40 2nd stage can also be set up to be left or right handed. This feature can only be changed by an authorised Apeks technician. Whilst this may have limited use as most training agencies stipulate that the regulators come over the right shoulder. It will be very useful if using the XTX 40 2nd stage as an octopus regulator.
What you will not get with the XTX 40 is a breathing resistance knob (also known as the cracking effort control) This is found on higher spec regulators. This enables the diver to finely tune when the regulator will deliver gas to the diver (i.e. crack open) I have this function on my other regulators and in truth I usually set the adjustment once and never touch it again. That said if you are changing gas mixes, or using a dive scooter or indeed diving in extremely tidal water (clipped to shotline after diving a deep wreck). This can be a useful tool. The XTX 40 also allows the diver to adjust the cracking point of the 2nd stage but it has no control knob to do this.  I was advised by the Apeks Sales Manager that the XTX 40 is user adjustable by using an allan key, when the reg is on dry land. (Needless to say care should be taken if using this feature). Divers should consider whether they require this feature. When I looked at the exploded chart for the XTX 40 against the next reg up in the range the XTX 50 the only difference was the inclusion in the latter of the cracking effort Controll.
The XTX 40 is therefore packed full of features and built to a high quality. I found it suitable for deep diving in cold water using a number of gases. I thought it was strange that  on the manufacturers matrix for their range of regulators the XTX 40 is not classed as a regulator for technical diving. I don’t fully understand this and I can only surmise that this is due to the lack of the Cracking Resistance Control as described above. Or perhaps special “o” rings included as standard?  Nitrox versions of this regulator are available. Unfortunately as there was a rush to go to press with this review I will have to contact Apeks and confirm the details re this in a following edition.
My own opinion relating to the XTX 40 is that for the money it is an outstanding regulator. Solid construction and packed full of useable features that meet the requirements of UK diving. Most importantly for Scottish divers is the excellent cold water diving performance. Balanced First and Second stages make breathing resistance minimal and the regulator I found performs beautifully and when compared to my recently serviced XTX 200. I noted very little difference 
Servicing of this regulator is good news too. This is a UK product and parts are cheaper that some imported models. Servicing costs for the XTX 40 with the benefit of its environmentally sealed First Stage should be minimal.
In this price range the XTX 40 would be my first choice regulator and in truth I would be hard pressed to justify spending more cash on a pricier model sporting features that I may not require.

RRP. £325
Best price I could find on internet £247

Mike Clark

Hi There,
Here is a link to my latest topside photos. Please feel free to have a look. I hope you enjoy them.


Sunday, 24 June 2012