running active and passive together

Well, since the specs of your preamp seem to be "unavailable" online and you don't list the gain figures for each stage, I can't give you a definite answer.

Does each stage work concurrently...both controlled by the common volume control? If not, your idea won't work; and if so, the active and passive sections would need to have the identical gain spec, which is highly unlikely.

So I'm highly doubtful that your idea would work.

Why don't you simply find a preamp with two pairs of outputs running off the same preamp circuit? There are plenty of those around... I have a B&K Pro 10 that has both active and a buffered passive modes and sounds quite respectable. They are quite inexpensive on the used market and have two pairs of RCA preamp outputs plus one Balanced XLR pair. You could easily power two separate stereo amps with it and have your choice of passive or active modes.

Yes i can run both together to the same volume control. I got the same set up now, Im running active mode with acurus and nht super zero with sub speaker, and passive mode on McCormack with Psb.
thanks.

Wow running those two different amps like that might not be the best idea. The McCormack is a lot better sounding amp than the Acurus, you might achieve better results running just the McCormack, but if you want to try bi-amping use the McCormack on top with the passive output for the mid/highs its better suited for the passive side of the MLD. The reason I suggest this is I'm not sure the Passive side of the MLD will drive the Acurus. A few things you need to know when connecting an amp to a passive preamp is the input impedance of the Acurus? What the capacitance of the cables that you are connecting your sources and amps are? And what the output voltage from your sources are? Even if you decide to use the McCormack to drive the mid/highs its still a good idea to know these values to achieve the best results because "A pure passive output is sensitive to cable capacitance, with low capacitance values being preferred". The DNA-1 was originally designed to work well with passive preamps. "For McCormack passive preamps, its suggested that you use cables that do not exceed a total of 1000pF per channel (less is better)". This come from Steve McCormack who designed the MLD and the DNA, you can read more about his passive preamps at SMc Audio on the Q&A section. I hope this helps. Also search here in Agon under Stevemcx read through his answers he makes a suggestion on how to set up the MLD for this type of configuration. Lots of good info in there to.

P.S. Also make sure the PSB Gold i can be bi-amped. Just because theres two pair of speaker connections they may be connected together in the speaker at the crossover.