"Vertical" biamping


Some have suggested the use of vertical biamping - two amps of the same model/brand powering all four inputs of my biwireable speakers. I'm curious to hear feedback from those that have attempted it.

It has also been suggested that it might not be worth it if your preamp doesn't support 2 pairs of outputs.

I'm curious to hear from those that have tried vertical biamping in general or possibly even modified their preamp to have multiple outputs in pursuit of this vertical biamping idea.

I'm using a Threshold FET 2 pre amp and a CJ/Sonographe SA250 that I would most likely buy one more of if I pursued this.

Thanks,

Phil
phil0618
Phil: The best way to biamp is with an active cross-over and bi-pass the speaker's crossover. I have done this to great effect. I have Martin Logan's which benefit tremendously by separating the bass and panel demands on an amplifier. With the active cross-over, you don't have to worry about having only one pre-out. If you can't go with an active cross-over, your results will vary depending on the speakers. In most cases, it will improve things, but to a varying degree, and in some cases not worth the extra $$, which might be better spent on just upgrading the amplifier. Hard to tell which is best without knowing what speakers you are driving.
I have used vertical biamping a little. I did it because I bought two of the same amplifier. They sounded good and weren't real expensive. It was a way for me to get more power with out spending a lot of money. I found that I had less separation loss if I were to do horizontal biamping. I am using this configuration now. My preamp now has two sets of outputs. I am looking to upgrade to an older conrad johnson preamp. Some of them have to sets of outputs, and some do not. I have to have two, becase creating a "y" off one output is a pain, and won't sound as good as if I had two outputs.

FYI, I hear that some of the anthem preamps that have two sets of outputs is nothing more than a "y" off the main output for a second set of main outs. I am saying this because I would assume someone with some electrical knowledge could take their preamp and do the same thing. Happy listening!
I was going through similar issues with VT100s and my ProAcs, so for an extra data point, I asked the US dist. He recommended horizontal, passive bi-amping. Never got around to tho', since I ended up with a new pair of Martin Logans.