In 1964 US Divers introduced the Royal Master. The first double hose regulator with a Balanced first stage.
To understand what makes these first stages different than those preceding them CLICK HERE for a detailed explanation by Luis.
The Royal Master only stayed in the US Divers line for two years after which it was called the Royal Aqua Master where it remained with minor changes until it was discontinued around 1973.
The balanced first stage is really the only difference between the Royal Aqua Master and the DA Aqua Master and parts are interchangeable between the regulators.
The constant IP pressure despite changes in cylinder pressure and easy breathing made the Royal a favorite of divers around the world. US Divers advertised it as The Regulator For Those Who Demand The Very Best.
One of the myths about US Divers regulators is that a crown sticker makes it a Royal...This is incorrect as Mistrals and DA's often had crown stickers on them. There is a way to tell a Royal from a DA even if the label is missing. CLICK HERE for info. Through the years many parts have been switched between the millions of regulators produced so it's a good idea to be sure you are buying what you think you are buying. A Royal Aqua Master is more valuable due to it's balanced first stage but we have often seen regulators with DA nameplates and Royal first stages installed in them.
All Royal Masters and Royal Aqua Masters up till 1967 came with short yokes but can easily be updated to a long yoke for use with a banjo fitting. Some late model Royals came with the heavy yoke and large plastic knob as was used on the Conshelf line of regulators.
Sometime in 1969 USD decided to change the face of the DA and Royal Aquamaster exhaust can to the large circle label. The company was known to be very frugal and used up all available parts before making new ones. It is not unusual to remove the circle label from the exhaust side can and find that it has the indention and tab holes for the earlier square label underneath. The collective thought on this is they simply re-stamped cans they still had remaining in their inventory for the square labels with the large oval recess for the new label till they had exhausted that supply and later manufactured regulator cans would only have the new oval stamping.
Another observation of mine is that the chrome on the later circle label regulators was not done to the standards of the earlier regulators and flakes off more easily.
As with the DA and Mistral series there is no need to pay a fortune for a Royal Aqua Master. They where made in huge quantities and one is just as good as the other. The one exception would be if you run across one of the 25th anniversary gold plated Royal Aqua Masters made in 1969. There is some conjecture if the regulators were given to each of the US Divers dealers or if they purchased them. I have heard it both ways and have in the past purchased them from dealers that said they could buy multiple units at the time. I think the facts about this are one of those great mysteries we may never know the whole truth about.
The Royal Aqua Master is a great regulator to dive with and one that most double hose divers have in their collection. All parts are available for them as are many new updates that enhance the performance of this great regulator. For a more complete family history Click Here
The above is a basic overview of the Royal family line of regulators. For further information and more details please visit the Vintage Double Hose Website and website message forum