Problems with my Berning ZH270

Don´t know what happen with my Berning ZH270 amp. I have Merlin VSM-M speakers and Electrocompaniet CD player. The amp is very fast and clear, but also bright, bright, bright.
I have tried Cardas Golden Reference interconnects, Nordost SPM speaker cables (and much more wires), without any improve. I have just add a LA-100 Joule preamp and things are now better, but not enough.
Tube rolling?. Another amp?. Wich amp (I would like to keep my new Joule preamp). Thank you.
George