Which is better? Mk25 or an Overbalance first stage?

[Bubbletrubble]

@DatSRBoi: Your reg is fine. Enjoy it. The underlying theme of what DA Aquamaster, herman, and mattboy are saying is that regulator manufacturers sling a lot of marketing BS at the consumer. Try to see past it. Realize that there are a lot of quality regs out there. If your reg isn't breathing as nicely as you think it should, your first thought should NOT be: "Gee, I need to sell this reg and purchase a super-expensive high-end reg." Instead, you should be saying to yourself: "I need to make sure that my reg is tuned properly. How can I do this?" Either learn how to do tune it yourself or take the reg to a trusted, experienced technician. Have fun out there!

[Edited later: Looks like mattboy posted before me. ]

 

[rcs9250]

We live and die by marketing hype. Many many many divers totally enjoy low end regs with no problems at all. We basically buy what we can afford/want/justify.
In PADI OW scuba class you learn that the most important thing in choosing a reg is ease of breathing. The regulator market isn't so massively large that junk regulators would survive the market place very long . Word gets out quickly of what is junk. Way to much money has to be invested to manufacture a reg that isn't going to survive the rigors of the marketplace.
How many people have the opportunity to test, say 4,5 or 6 different regs. You go buy what the salesperson told you or maybe an article in a magazine or a friends recomendation. I personally am always skeptical about magazine evaluations that have ads for the manufacturer. It's like the bosses little suck up, kiss ass getting a bad review.

Most often the low end regs material choices for things like purge buttons suffer making them hard to push. But as for breathing don't breathe all that bad. Some octos however are really poor in the work of breathing area. But typically that is passed off as "oh well, at that point the dive is over anyway, the guy would be able to suck start a Harley at that point".

 

[herman]

The really dumb thing about the supposed "overbalanced" bit is that the higher IP just means more pressure in the 2nd stage balance chamber pushing the seat closed, so it pretty much washes out; it's adding pressure in both directions. There is the highly dubious "higher IP means higher flow" idea, but since the 2nd stage is the limiting factor in flow for any regulator, increasing the IP will not result in any more air flowing in normal use.

But, people still fall for it as demonstrated above.

I tend to run my MK5s and MK10s at 125PSI for IP, which is the low end of the spec. As the seat wears, IP is only going up.

From a strickly technical point of view, a higher IP will create more flow through a given orifice- basic physics but that is based on a completely open orfice with no obstructions. Once you add in the LP seat and the springs throttling the flow because the demand for that much flow is not there...second stages are demand valves after all, then for all practical purposes you are dead on, a higher IP will not result in a higher flow to the diver.....maybe higher flows during an uncontrolled freeflow...exactly what we don't want but during use it makes no difference.

My head hurts. I have more learning to do. So would that mean my DC2 212 hollis reg is not that great? I know there regular price was 600+ and they dropped it to 279 due to that swivel copyright issue. I guess I fell for the overbalance thing. Wonder if its a good buy now.

If you really care to understand what is going on in your reg and I highly recommend everydiver do so, get yourself a copy of "Regulator Savvy". It explains the how and whys a regulator works and the physics behind it. It's not a complicated read but once you understand how a reg works you can sort out the BS from the facts for yourself. IMO it should be a required read for all divers. Scuba Tools - Regulator Savvy Book

 

[Texfrazer]

If you really care to understand what is going on in your reg and I highly recommend everydiver do so, get yourself a copy of "Regulator Savvy". It explains the how and whys a regulator works and the physics behind it. It's not a complicated read but once you understand how a reg works you can sort out the BS from the facts for yourself. IMO it should be a required read for all divers. Scuba Tools - Regulator Savvy Book

Don't forget about Vance Harlow's (Oxyhacker here on SB) excellent book also. Both are great and really are must read's: Scuba Regulator Maintenance and Repair

 

[herman]

Don't forget about Vance Harlow's (Oxyhacker here on SB) excellent book also. Both are great and really are must read's: Scuba Regulator Maintenance and Repair

Absolutly, I have both. IMO RS a little better on the technical side- more detailed if you will- as opposed to SRM&R which is a little more on the hands on-DIY side. Both are well worth having.

 

[Packhorse]

Lets face it, if its over balanced it can not be balanced can it.
So the question remains "do you want a balanced or unbalanced 1st stage?"
Answer ( for me) I dont care. Give me a great 2nd stage.

 

[herman]

Lets face it, if its over balanced it can not be balanced can it.
So the question remains "do you want a balanced or unbalanced 1st stage?"
Answer ( for me) I dont care. Give me a great 2nd stage.

If you get picky with the def of "balanced" you can actully have both. Strickly speaking, the term "balanced" when used in scuba reg first stages means the reg keeps the IP constant as tank pressure varies and has nothing at all to do with depth. On the other hand, all regs are depth compensated, they all increase the IP to match the increase in ambient pressure on a 1 to 1 basis. The so called "overbalanced" regs are actually "over depth compensated" because they do increase the the IP of the reg at a slightly higher rate than the typical 1 to 1 ratio, it's somewhere in the 1 to 1.3 range. So in fact you can have a balanced and "overbalanced" first stage at the same time.....but I am with you, give me a good second stage.