your experiences bi-amping using passive pre-amp?

I think bi-amping is a great idea. I used to biamp a pair of Alon 1's with a heavily modified Dyna ST-70 on top, and a solid-state ARC D-100b on the bottom. I did this with no preamp. How, do you say? I put a Y-splitter on the variable output of my NAD 5000 cd player, and just used that to control volume. Not bad for my college days. My guess is that as long as you have a source with higher-than-average output, you should be fine. Which passive pre and amps are you thinking about?

Technically speaking any biamping without active crossover sucks. But if you deside to try, passive preamp isn't a problem in this case. Just make sure that pair of your amps can match with passive and your sources meaning gain, input sencitivity, input impedance...

I've been bi-amping for years using a passive pre-amp (Reference Line). There are two ways to do it, passively & actively.

PASSIVELY : Using the same amp(s) really makes life a lot easier since you don't have to fuss with level adjustments between amps & drivers. The best settup is 2 identical stereo amps or 4 identical mono blocks with a gain of at least 26 DB. You also need to keep an eye on the input impedance of the amps. It should be at least 40K ohms.

If you have another set of outputs you have a choice of splitting the signal at the pre-amp or just running the signal to the amp(s) and doing the splitting there. I recommend splitting the signal at the amp...less wire. There are several splitters available. I've used the ones marketed by Monster & Vampire wire that look like plumbing tees. They plug into the back of the amp and have two female RCA input/outputs at right angles to each other. Then I simply run a short section of the SAME wire to the other channel/amp. What ever splitter you use, make sure it is of high quality.

If you are running mono blocks the debate over vertical vs horizontal bi-amping does not apply. If you use 2 identical stereo amps I prefer just keeping the amps behind the speakers and using one channel to drive the lows and the other to drive the highs. Again less cabling is involved (usually a 1/2 meter section is all that's needed to act as a jumper between channels). The best way though is to install an internal jumper between the inputs on the inside of the amp. But that's a modification. The other thing you need to be mindfull of is that that some amps may not like having their inputs paralleled. Best thing to do is talk to the OEM.

ACTIVELY: Really simple here. The active x-over will act as a buffer for the passive pre-amp. Just keep the cabling to x-over short & simple (no funky box thingies)and make sure the x-over has an input impedance of at LEAST 20K ohms. There should be considerably less debate here over the choice between vertical & horizontal bi-amping.

Don't let anybody talk you out of trying passive biamping. Done right, and it will make a considerable improvement. Hope this helps and good luck!