Ivan FX - Liam

I don`t believe indeed that G68, as any pre-amp in the world due to a their typical very low output impedance, is going to be “stressed” due to a parallel (Y) connection. The output impedance of G68 is 47Ω (3,5V is the max out voltage-max volume) that compared with the high one of any of power amp input, typically 20-60 KΩ,(mine are 47KΩ) is nothing, even those reduced to half of its value due to the Y connection; the influence is irrelevant and “Y” Vertical and Horizontal Bi-amp is a correct adopted way.

I personally run passive bi-amping, having had available two pairs of ClassA mono amps (Marantz MA24), being of relative low power (30W), I`ve decided to drive the two sections of my speakers separately.

Well, I sure perceived an immediate benefit jut for the availability of more power. Different story is the general quality performance; in my case I had just a subtle improvement - anyway I`ve to admit it was worthwhile and I`m happy with.

Of course the real bi-amp benefit you`ll get going active, by means of a good electronic Xover, no question!

Driving the two Amps with a reduced frequency spectrum managed by the Xover you`ll gain in precision, lower distorsion and huge dynamics (mostly on the Amp devoted to the High frequencies), moreover you can adopt different Amps with different characteristics gain and power (Higher for bass section lower for high section).
The downside is that you`ve to exclude completely the internal Xover of the speakers, connecting the Amps directly on the drivers and usually these are perfectly calibrated/tuned and designed for that speaker configuration. It can be very hard to find exactly the same tune calibration setup with an external active Xover without proper expertise and instrumentation and just by hear trial&try process.
Of course once got the point ……

Cheers

Ermanno
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MY KIT: G68ADV(1.44)-G98DH(2.47)-Denon 2900SDI- Marantz MA24x4(Bi-Amp)-Marantz MA500x3-Sub AudioPro B270 -Electrovoice Sentry 100A- Sonus faber centre surrounds- DVDO HD+ -Panasonic 42PHD8- HTP(self assembled)& Accessories.