What would I gain using an adjustable, balanced 2nd stage?

[JKSteger]

I have a balanced 1st stage Scubapro MK10 but I have only used R190 with it. I've thought about upgrading my 2nd stage to a G250 but the price is extremely high for me.

How much of a difference would an adjustable, balanced 2nd stage make with the SP MK10 1st stage.

Could I also pair up the MK10 with say an Apeks 2nd?

Thanks,
Jeremy

 

[redacted]

On shallow easy dives with the R190 tweeked for best performance, you would be hard pressed to tell the difference. But dive deeper or in adverse conditions (current and surf), work a bit more than you care to, or get the R190 tuned so you are confident it won't freeflow and the g250 difference will be readily noticable. OTOH, you can do a lot of good diving with an R190, if that is what the budget supports.

That Mk10 will work fine with most 2nds.

 

[halocline]

I agree with awap, but I'll add this. Why don't you look for a used SP balanced adjustable (metal case, maybe it's 109) 2nd stage, or an older style G250? Either of these can be found on ebay for a reasonable price, usually $50 or so for the 109 and hopefully less than $100 for the G250. Note that this is not the current G250HP. Either of those 2nd stages can be easily rebuilt to perform as well or better than the newer G250HP, and will match well with your MK10. If you go this route, there is a great SP tech who frequents this forum who might agree to rebuild it at a very reasonable price.

I have one each of those 2nds, as well as a R190. I've hooked up all of them with my MK15 to compare, and you'll notice a difference. But, my R190 is tuned to my MK2 at a significantly higher IP so it wasn't exactly a fair comparison. The 109 balanced adjustable is a GREAT 2nd stage IMO, you just have to make sure you have a good mouthpiece for it as the metal case is a little heavier. It really does help with drymouth though, and the bubble dispersion is really comfortable with that nice wide rubber tee.

 

[DA Aquamaster]

A new G250HP retails for something like $330, so it is a pretty significnat sum of money.

And I agree with Mattboy that a Scubapro Adjustable/Balanced Adjustable will give you 99% of the performance of a G250 HP (they lack the G250's adjustable flow vane that most divers don't adjust much if at all anyway) for about a 1/4 to 1/3 rd the price once you buy it, upgrade and service it. And it will match the chrome on your Mk 10, be period correct and will wear better and last longer than a graphite/epoxy resin (ielastic) cased second stage. I have several of my own and some were originally made in the late 60's but still look very good and perform better than they did when they were new.

They are almost impossible to beat in terms of performance per dollar and, once upgraded to the current Balanced Adjustable configuration, use the same poppet assembly as the G250HP and S600 so annual service parts availablity will not be a problem anytime soon.

If you do want a more modern regulator I have a near new (3 dives) X650 second stage that I would probably sell for $225. I bought it for cold water evaluation purposes and it's a great regulator, just not quite as great as my all time favorite D400's (which are another less expensive but great performing used second stage ption to buying a new G250HP.)

 

[oxyhacker]

Interestingly enough, the tuning directions for many older design adjustable 2nds say to tune them with the adjuster in the easiest breathing position, so you do not gain any significant breathing improvement - a properly tuned G250, with the adjuster all the way out, breathes exactly like a G200B which doesn't have the external adjuster (newer ext adjustable 2nds may have a second adjustment which makes it easier to tune them to take full advantage of the external adjuster). So most of the improvement you will see if you upgrade will be due to the more sophisticated design of the 2nd rather than the presence of an adjuster.

That said, I still like external adjusters. The main advantage to them, as I see it, is that they give the user a little control over the tune, should the reg start leaking or freeflowing in the field - one of the most common post-servicing probs is 2nds freeflowing if they've been tuned to aggressively, or as the soft parts take a set.

I think the suggestion to look for a decent used G250 rather than buying a new one is a good one. I'd stick to SP too - the balanced SP and Apeks 2nds are pretty much equivalent, and you'll find more used deals on SP.

I have a balanced 1st stage Scubapro MK10 but I have only used R190 with it. I've thought about upgrading my 2nd stage to a G250 but the price is extremely high for me.

How much of a difference would an adjustable, balanced 2nd stage make with the SP MK10 1st stage.

Could I also pair up the MK10 with say an Apeks 2nd?

Thanks,
Jeremy

 

[JKSteger]

Thanks guys,
I will keep an eye out for a R109 or D400 2nd stage. I'm really not wanting to spend more than say $100.00 for a used one since I would have to get it serviced.

DA, you know anyone that has a R109 that would want to part with it. (I know I may post a WTB over on the Classified forum).

Jeremy

 

[ericpitar]

I've recently aquired an R109. I am about to have it overhauled and wondering if it's worth "upgrading" it to a "balanced adjustable"? I'm in the tropics so most if not all of my dives will be in warm water. 120ft max +-20ft.

thanks.

e

 

[Packhorse]

Im not sure how much bennifit you will get but for the cost you may as well do it.
Its a spring ( $13 nz in nz) and a service kit for a G250. Although the older G250 service kits have the poppet included I am unsure if the new ones do.

 

[Kupu]

The main advantage to them, as I see it, is that they give the user a little control over the tune, should the reg start leaking or freeflowing in the field - one of the most common post-servicing probs is 2nds freeflowing if they've been tuned to aggressively, or as the soft parts take a set.

This is exactly why I no longer like to use non-adjustable second stages, especially when going on longer trips. I have had annoying problems with slight freeflow after servicing, after switching to the adjustable second stages, it is now easy to take care of the problem.

 

[DA Aquamaster]

The most recent kits released by SP come in a large package, do not have the poppet but have an ungodly number of o-rings that you can't always use.

OItherwise the spring is about $2, the balance chamber is also around $2 and the poppet should not be too much more than that - so figure $6-8 in parts plus the G250 annual service kit.