What about bi-amping? When does it make sense to run two amps instead of one? Let’s massage the topic.
The theory behind bi-amping is, it is better to run one amp for the mid & tweeter array and another for the woofers- as opposed to having one amp drive the whole tower and have to fight its way through a bigger crossover network.
The back EMF of a woofer is tall task for any amp to handle. To deal with that AND to control the mid/tweet array exquisitely, is a lot to wrestle. You’ll invariably get superior sound if you dedicate one amp to the woofs, and a second to the mid/tweets. Buttt…
Bi-amping is often a bag of cats. Which electronic crossover will you use, if any? One better amp typically sounds better than two amps that are half the price. It comes down to details.
Bryston A2 Speakers, $4000 Per Pair
The smartest way to bi-amp is to start with speakers that are built to accommodate two amps. A great choice, and my example here, will be the Bryston A2 towers.
Please note from our photo that there are two sets of terminals on the rear.
There’s an upper set that connects to the midrange and tweeter drivers.
There’s a lower set that connects to the woofers.
When you unbox your A2s there is a brass jumper bar that connects the two sets of terminals. In most cases you’ll run your amp into EITHER the upper or lower binding posts and you’re ready to go.
But what if you want to improve your sound by bi-amping? Here’s where the fun begins.
In theory, it’s easy with Bryston. Just take off the jumper bars.
Run one amp into the woofers.
Run the other amp into the midrange/tweeters.
Physically, this is no big challenge. You just need two amps and two sets of speaker wire.
Atoll Amps
Most of the time we feel it is better to run one strong power amp instead of two lesser amps. Let’s use the marvelous French Atoll brand for this discussion.
Atoll makes the outstanding AM100 ($1500, 100×2).
Atoll makes the outstanding AM200 ($2200, 120×2).
Atoll makes the outstanding AM300 ($3900, 150×2).
AM100 will do a very nice job with A2s. But of course AM200 is better due to bigger filter caps and double the output transistors. AM300 is better yet in that it runs a pair of LARGER transformers and even more output transistors.
I would prefer to run one AM200 instead of two AM100s.
I would prefer to run one AM300 instead of two of AM100s or AM200s.
Where bi-amping makes the most sense to me is when running TWO AM300s. Use an Atoll preamp. Run one set of pre outs into one amp, and the other set of pre outs into the other. Connect one amp to the upper terminals, and the other to the lower terminals. You’re set!
This works because you’re running two amps with the same input sensitivity. If you run two different brands of amplifiers you will now need an electronic crossover.
Rarely, will it make sense to do this. Almost everyone who wants to bi-amp goes online to buy a Behringer or competing $300 Chinese built crossover. You’ve just dumbed down the quality of your system. You started with a 6” pipe of water, but reduced it to a 1” pipe when you run through the Chinese crossover. It will cost you a solid $3500 to get a commensurately built JL CR-1 crossover, that would do the job well.
To be clear, I’m recommending the larger Atoll amps vs a pair of little brothers.
The catch is, we sell a fair number of AM100 and AM200 amps. Not everyone can afford AM300.
If you already have an AM100 (or AM200) and want to up your game, you can buy a second matching amp and run bi-amped as I’ve described above. That would be more cost effective than trading in your AM100 (or AM200) towards an AM300.
In short, if you plan on bi-amping, it does make sense with a pair of AM300s.
Or… if you already have an AM100 or AM200, it would make sense to buy a mate and bi-amp in this configuration. This way you don’t take a hit on a trade.
Bi-amping done right gives you stronger bass, a bigger kick and better clarity in the middle and upper end. If you do it right, your dynamics will soar! But you have to do it RIGHT- as my options have laid out above.