Hi Zszwedo,
I had very good experience with Accuphase and Musical Fidelity (MF). A MF
integrated like KW-500 or KW-550 will be a very cost effective solution.
However, your choices are probably endless, e.g. Graaf, Jadis, ASR, Pass Labs,
YBA, Rowland, etc. I agree with Atmasphere that the Altos sing very very nicely
with tubes.