Noticed in the review (in English of course) that the AMG STA seemed to work well with preamps having lower output impedances. But my STA-9 works beautifully well with my Musical Paradise 701 mk 2 pre with an output impedance of 2kohm so was wondering if the AMG STA would not have issues with the Musical Paradise? Am considering between an STA-9x and the AMG STA. Dual power amps in the future.