Quote Originally Posted by avddreamr View Post
Well, am I to interpret that you prefer the older design?
There was no inkling of preference in the statement that I made, it was merely a statement of fact based on the PQ curves provided by Swiftech.

When lang revised their ddc-1, and ddc 2, into the 3.1, and 3.2 models, they both seem to have lost some psi, the 3.2 significantly. I have two ddc2s, and I'm waiting on a 3.1 that should arrive today or on monday. What do you feel where the design advantages when they elected to do the revisions in such a fashion?
Most of the advantage in the redesign was Laing's since they only had to produce one pump instead of two--the original DDC-3.1 and 3.2 are identical, save one solder pad bridge which acts as a toggle between modes. Obviously, this approach would increase the profitability of the pumps by lowering production costs. There were a couple changes which benefited the end-user, though, like a substantially softened startup sequence (no more 4A startup spike) and improved reliability (about 1 in 20 DDC-2's that we sold ended up failing).

Generally, i think the goal is to keep it at or above 1gpm. Did you feel that you got better performance out of the ddc 1, using your top for instance? In my case, i noticed that I had to run the ddc2 at maybe 50 percent, to gain an acceptable noise profile. So I am not running my pumps in their optimum range, and the extra pumping power is lost on my low resistance loop. (fuzion v2, xspc rx360, danger den ion g92, ek nforce rev 1.1) So if someone was going to use a ddc 3.1 in a low resistance loop, wouldn't they stand to benefit? Or is that not representative of most of the people who would buy the 3.1, and they would of been better served by the original design? Would any of these conclusion apply to the design shift from the ddc 2-> 3.2 or even the 3.25?
The overall performance difference between the DDC-1 and DDC-3.1 is pretty small, to the point where I'd say it doesn't matter. The DDC-2, however, offers higher flowrates than the DDC-3.2 across its entire operational range at the expense of some reliability and slightly higher power consumption. Unfortunately, I haven't had an opportunity to experiment with the DDC-3.25 just yet.

Quote Originally Posted by nikhsub1 View Post
Well I have had my 2 DDC-2's running 24/7 for almost 4 years now... not 1 issue to report other than no issue
I still have working DDC-2's as well, Scott... but that doesn't seem to make people feel better about the boxes of DDC-2's I had to RMA back to Swiftech