velodyne DD hook up

rca single from pre-out to y at sub in---no problems and sound quality and speed great but if you're running 15 feet or more to your sub you should consider balanced xlr

Depends on the preamp. XLR output is pointless, as DD has only RCA inputs (except for one XLR LFE input for HT.) A Y-connector bridging L/R outputs of preamp works only if the preamp outputs are internally buffered. Otherwise outputs to main amp will also be bridged into mono.

Because my Atma-Sphere preamp briefly emits DC off-set when it's turned on, I buffer line-level outputs to DD sub with Jensen Isomax coupling transformers optimized for LF use. But this is not a typical configuration.

As I'm in the process of putting my rig back to gether again just this week,I've coupled two sets of no name RCA ICs using only one side from my Onkyo Receiver...

In the past I've run via this same cable (s) from both my Bel Canto DAC3 and Thor preamp. On the Thor I had to use a pair of "Y's", as it has only one set of active RCA outputs.

I've detected no adverse issues in the sub's sonics in any of the above configs.

I will be spending more time this go 'round in placement, and will ultimately go with one run of RCA cables to the sub... personally, I like the idea of using a preamps outputs, rather than an added set of speaker cables.

Thanks for the replys