Bi-amping

If you don't bypass the internal crossovers and use an electronic crossover prior to the amps there will be little, if any, benefit from using two amps.

I don't see any useful benefit for biamping for you. Unless perhaps you intend to run the amp into clipping regardless. Then you might get some protection for your tweeter.

Bi-amping does not double the power to the speakers. A single 125 W amp can provide 125 W to the bass and treble. Splitting into two bands you still have a maximum of 125 W in each band. As mentioned above, if you are driving well into clipping you would probably still clip the bass amp but probably not the treble since the higher frequencies generally require less power. However, the only way to send 250 W to either (or both) band(s) is to buy a 250 W amplifier.
Edited by DonH50 - 1/22/13 at 11:44am

Yeah, take it from many that have tired passive bi-amping and bi-wiring. Not much really takes place. Try it of course, so you can see for for yourself. What really makes a difference is; a bigger badder external amplifier to feed those hungry speakers.

IF YOU FEED THEM, THEY WILL PLAY

^^^^the only way to get 250 watts into each speaker is if your adcom amp
was bridgeable.

It is not!!! What you are proposing is passive biamping. What the other
Posters say is correct... Small benefit at best.

If you want more power to your speakers you need to purchase a more
Powerfully external amp. (Emotiva)

Hi, I read your post and I have one similiar,, BUT, I do have 2 Adcom gfa 550a amps at 200w per ch both driven and they are bi-ampable.. Both only have about 50-60 hrs on them and not a scratch, if you are interested in coming up to nice power bi-amp do-ables, let me know by reply. No home runs hit by me in selling and sharing fine equipment with others who appreciate! bob800adcmlogn,, Bobby G

Sorry, it's bob800adcmlogn here.. the amps are 555's

Absolutely, it's a great idea in theory, but as said here, you need to be able to bridge them. Emos are bridgeable.

What he has can do bi-amping quite well for all it's worth...

...that's the problem, bi-amping isn't worth it.

Now, are your 555s bridgeable? His 5400s aren't.

btw. Adcoms are great amps - I have a GFA-535 in my 2.1 system

What they're saying, or should be anyway, is that it doesn't matter. What determines output isn't power, it's voltage swing, and what you propose will give exactly the same voltage swing you have now. Output will remain the same. The benefit to bi-amping lies in reducing distortion, by removing the passive crossover and by separately amplifying two reduced bandwidth signals rather than one full bandwidth signal. With the high quality passives used by B&W the improvement realized by bypassing them probably will be slight, perhaps too slight to hear, and the reduced IM distortion alone may not be worth the added system cost. You'd gain some additional headroom in the amp used to drive the HF section, and that might be audible. But it might not.

yes they are and I actually have four of them..Bobby

Note the 603 specs list 3 ohm minimum impedance, a value too low for many amps in bridged configuration. I am not sure Adcom specs their low limit in bridged mode. They are 8-ohm nominal so might be OK but I would watch the amp (since Adcom's tend to run hot anyway). Bridging effectively halves the load impedance seen by the amp, so that 3-ohm min becomes 1.5 ohms to a bridged amp. I know Emotiva will not warrant their amps for less than 8-ohm speakers in bridged mode, although Adcom by all accounts (and past experience) will drive lower impedance loads fine in normal mode.

I recently did this, but it's not as easy as just bi-passing the x-over and hooking up an external, electic one. In my case, I was able to buy an amp (actually 3 amps) that has preset DSP values installed for my specific speakers. Otheriwse I would have had to take measurements and tweak, tweak, tweak. Among the DSP variables are crossover, delay, EQ filters and output limiting. A little daunting unless you are comfortable in setting these.

There are programs that simplify it, like RPlusD with the speaker filter option, but of course you must buy the SW, any needed HW, and learn how to use it all...