[84olds]

I have two Parasound Z Amp v.3.  I would like to run them bridged, but Parasound doesn't recommend running them bridged on speakers rated less than 8 ohms.  So I currently run each amp in stereo, have removed the jumpers on my Kef and run one one amp for highs and one amp for lows.  This has led me to wonder: What load does the amp see when jumpers are removed?  Are partitioned crossovers more likely to dip and have unusual loads?  Does the manufacturer ever have specs or values available for the different ways their speakers might be configured?  Said another way, does a four ohm rated speaker have 4 ohm high section and 4 ohm low section when driven separately?  Just hope for the best?

Incidentally, the Z amps simply send the signal on from another set of RCAs and appears to be the same net effect as splitting the signal with a y adapter cable.  Nothing special going on there.  I suspect this is why it required relatively high volume setting on my pre to get good volume.  It's been an interesting experiment, but will be going back to one (beefier) amp. 

[toocool4]

I have ran ams bi-amping horizontally and vertically, both gave great results. I started horizontally like you are doing now, it worked well. Vertically was good too as I separated the left and right channels by running mono blocks.

In your case the part that will create the bigger load is driving the mid / bass drivers, so more likely to see the lower than 8 ohm load when the frequency drops. The tweeters require much lower current, you are more likely running it the best way for your current  amp specs.

I don’t think the amp will see anything  more difficult Than it saw before, the amp doing the tweeter will definitely have an easier time.

You should not need any higher volume setting on you pre-amp just because you are running bi-amp, if you do something is wrong.