I understand the view that passive bi-amping is a waste of time. However, over the last 3 years I've replaced all the components of my stereo system except my power amp (Quad 909). Indeed, I tried a Classe CA2200 in my system at home a while ago and actually prefer the sound of the Quad!
I now have a range of perfectly good components sitting unused in a spare room and have just bought a second hand 909 from Audio Emotion at a fantastic price. The plan is to use it in a second system. However, it will also be fun, if ultimately a waste of time, to try bi-amping with the 909.
My query is this: is there any risk that the two 909s might be inadvertently damaged by sharing outputs from the preamp? Here are the details: my preamp (Music First Classic) has two sets of outputs, call them A and B. The signal out from right channel A is simply wired with a one inch length of wire to signal out right channel B, and the same is true of left channel A and B. Using these two sets of outputs to bi-amp is effectively like using a Y-splitter. So, if I bi-amp by using one 909 to feed the woofers on both speakers and the other 909 to feed the midrange/tweeters, aren't the right channel inputs on both 909s connected at the preamp? Likewise, if I bi-amped by using one 909 per speaker and took preamp right channel from output A to one input on the 909 and took preamp right channel output B to the other input on the same 909 (and then used one set of poweramp speaker connectors to connect to the midrange/tweeters and the other to the woofers of the same speaker), aren't I effectively connecting the right and left channel inputs on the poweramp at the preamp end?
It might be that these problems are non-existent, but I'd thought I'd check before potentially causing any damage. I've checked with Music First who state there is no issue with impedance when using their preamp for biamping, and Quad stated the obvious, i.e., remove the connectors between the two sets of terminals on each speaker!
Many thanks for any help.