Berning ZH270 and the Infinity Kappa 8’s

Hi All,

I was fortunate enough to purchase an excellent amp from a respected Audio pro here on Audiogon. The amp, a David Berning ZH270 made my Kappa 8’s (driving the mids and highs) finally sound present, full and without any sibilance. I have been searching for years for this! I am using a BAT VK-500 on the lows. Also amazing. Both these amps have obviated my need for digital room correction. The bass has only a narrow hint of bloat now (where I need some better room treatments) and has become very tuneful and ultra fast.

The only thing that seems a bit lacking is some shimmer above say 12 kHz.  Can anyone suggest why this might be and/or what I can do to get a little boost there. Upgrades or the best tubes for the Berning? Time for some Kappa crossover updates maybe?

Oh and...

1) Does anyone know how, if you have lost those paper markings on the infinity wiring, to tell which wires are positive and negative wires to the polydome midrange? I just want to be sure...

2) Are the rear tweeters on the Kappa 8’s out of phase with the front tweeters?

3) Is there anyone out there who I can trust to upgrade the infinity crossovers?

Thanks much!

-brett