Passive bi-amping works ?

Thanks. Can you list some pre-amps which have 2 outputs ?

ryllau, there are many pre's that have more than one set of main output connectors. but, i woodn't necesarily use this as the criteria for choosing a preamp. there are quality adaptors that allow ewe to connect a pair of i/c's to one output. even tho my pre has *three* outputs, i still have to use adaptors, because i use an active x-over which has only one set of hi-pass outputs. i run a pair of amps from my hi-pass outs to wertically bi-amp my monitors.

but, when bi-amping, ewe *do* have to be even more aware of impedance mismatches - adding a second amp to yer pre effectively lowers the input impedence the pre is seeing. for example, if ewe are using two amps rated at 20k-ohms input impedence, the preamp will *see* a 10 k-ohm impedence. and, longer i/c's, which can be attractive in a wertically bi-amped set-up, to reduce the length of the speaker cable, can further exacerbate any impedance mismatches. basic rule of thumb is that yer amps' input impedance needs to be *at least* ten times greater than the output impedance of the preamp, & in some instances, even this amount may not be enuff.

hope this helps, doug s.

It only makes a difference, if you use different amps. If the amps are not underpowered, then two should sound essentially the same. If power was the issue, then significant gains can be had. I passively bi-amp, but with tubes on top, solid state on bottom.

fletch, my experience differs from yours - one of my electrocompaniet amps is enuff power to drive my monitors, but it sounds better w/a second matching amp, using one amp per monitor, vertically bi-amped.

ymmv, doug s.

I have a pair of Legacy Classics I am driving with a Sunfire Cinema. I have tried driving them with single channels then biwiring and then passive bi-amping and there was a steady improvement in the sound. More highs and lows with each change and better clarity and definition. A rather interesting thing, which I can't explain is that the speakers response got much flatter when I went to vertical biamping (as confirmed by my SPL meter). I had a +3 to +5 dB boost over much of the bass range and after the vertical biamp, it's now +-1.5 dB down to 40 Hz. Now I'm just waiting for the funds to go with Active crossovers...