I started out with a Healthways Scuba regulator in 1959. It was the first double hose, and I liked the smoothness of the breathing. But I switched about three years later to a Healthways Scuba Star, and dove it for about two years. Here's a photo of me back then in Puget Sound diving the Scuba Star regulator:
The Scuba Star was not a good performing regulator, at least in the beginning. It was a tilt valve second stage, and did not pass much air. I got another one about two years ago, just to have one, and put it in the pool. I must say that my youth and enthusiasm for diving probably mitigated some pretty poor design for the Scuab Star when I was young, as I only dove it once in the pool, and that was enough. But with only five moving parts, the regulator itself was almost indestructable (except for the LP diaphragm getting harder).
If you'll look at the Champion Arbalete speargun in the photo, you'll see it has a weighted head. I thought that would be enough for even the biggest fish, but on this dive I spotted a cabazon between some pilings. It was a large cabazon too. I aimed between its eyes, and pulled the trigger. The spear bounced off the fish's head! And, of course, it did not stick around for a second shot.
On another dive during this period, this time in Hood Canal between two old piers, I took that gun and finally found a target, a kelp greenling. This time, I was a better hunter, and shot it in the spin from above, just behind the head. It died immediately. We were in about 35 feet of water at the end of the pier and on the bottom. I was taking the fish off the spear. As I was taking the fish off the spear, I looked around and saw a fishing weight bobbing beside me, with a line leading to the surface, and a leader of about 3 feet with a hook on it. There was a storm above, so I was sure that no bubbles would give away our location. I looked at my dead fish, and the hook at the end of the line, and decided to do it. I took the hook, and imbedded it deeply into the jaw of the fish I had just killed. I then pulled hard on the line, and watched as the dead fish spiraled toward the surface and beyond. My buddy and I then swam to the second pier, and surfaced under it in about ten feet of water. As we were swimming in, I saw an older gentleman walking off the pier, fishing pole in one hand, and the hand of what must have been his grandson in the other. The grandson had the fish. I've always wondered what the old man said to his grandson about that dead fish that they caught.
My third regulator was an AMF Voit single hose, called the V-11 Viking 40, which came out in 1962. It was a great breathing regulator for the intake, and exhausted through the diaphragm. The USD equivalent was the first Calypso regulator. I used that regulator for about eight years, until I was in the US Air Force, and we went to USD Conshelf and MR-12s.
I now have two more USD original Calypso regulators, and it is becoming a favorite of mine. I've used one that I set up DIR wise, with a long hose, and a second generation Calypso second stage as a safe second. The second generation Calypso actually performs worse than the original Calypso, probably because the exhalation valve is the same size, but the air must bounce off the diaphragm and then down to the valve, necessitating a larger valve (which came out later); this second generation is also a wet breather, whereas the original Calypso is dry. Both regulators work as well as new after minor reconditioning (I put a silicone exhaust valve in the Original Calypso's diaphragm, which makes the exhalation even easier--it came from a Scubapro Shotgun snorkel). This regulator is now 45 years old, and a great-performing regulator.
John