First, I think you will notice a definite improvement with going with a quality preamp. You use 220v so I'm not sure where to have you look. I'd highly recommend some of your home land gear such as Arcam and Creek, or if affordable Linn and Naim. If you can find Conrad Johnson that are 220v compatible they are very good and obviously my first choice. I've been extremely impressed with the capability of mine, it allows micro and macro dynamics like I haven't heard until preamps twice the price.

It depends also on the type of sound you like. I find CJ and Linn more involving or musical where the others will tend to be more analytical in general. Neither being a negative, just different presentations.