What’s the Right Power Amp Ratio For Bi-Amping?

Update:
I’ve located and purchased another NAD 2700 amplifier, so I’ll have a pair of identical amplifiers.

I’ll now have 3 options: vertical bi-amp, horizontal bi-amp, or bridge and power left and right separately without bi-amping. Vertical bi-amping seems to be the preferred way, as mentioned by @racamuti , @almarg and @georgehifi, so I’ll try that first.

Bridging seems too extreme by the way, as I’d end up with the capability to produce 400 watts per channel, probably ten times what I’d ever need during normal listening sessions with my relatively efficient Energy Reference Connoisseur 30 speakers in my 12’x12’ listening room.

I will experiment with shorter speaker cables, from the 8ft 12 gauge cables I’ve used with the 3225PE/3020i setup, I’ll be able to go to 3ft 12 gauge cables with the 2700s sitting beside the speakers. I’m not expecting any audibly noticeable improvement, but maybe I’ll be pleasantly surprised.

Thank you everyone for your input! This is is going to be fun!

Bridging seems too extreme by the way, as I’d end up with the capability to produce 400 watts per channel, probably ten times what I’d ever

Not only that, but also sound quality is worse. As everything measured parameter that makes an amp a good one takes a hit when you bridge. The only plus you get is the extra wattage when you bridge, and if you don’t need it, then you actually go backwards in sound quality.

EG: Bridging Amps
CON’s:
Higher distortion
Lower current
Lower stability
Inability to drive as low impedances
Lower damping factor
Higher output impedance.

PRO’s:
Higher wattage.

Cheers George

Well, I received the second NAD 2700 amplifier this week, and wired it up with the other 2700 to vertically bi-amp my speakers.

Love the newfound benefits of not being power-deficit anymore. There seems to be substantially more detail in the midrange, which is handled a little differently by my Energy Reference Connoisseur 30 speakers. They have a three way design even though they have two identical woofers and one tweeter, designating one of the woofers as a midrange driver. 

Now getting back on topic, checking heat output of the two halves of each amplifier, the sides that drive the woofer / midrange is *much* warmer than the sides that drive the tweeters. That unscientific evaluation suggests there is a distinctly greater amount of power dissipated by the low frequency side of the bi-amp split. I haven’t yet figured out how to empirically measure this, but the first stab will be using my infrared thermometer. 

In the meantime, I’m no longer power hungry 😋 

There is not one. Just go for quality, best low end, best treble etc. You like tube high end, but maybe you like SS bass. Forget about power although the more you can afford the better.