It depends on the bandwidth of the transformer, but current irregularities pass via inductance along with the intended 50/60 cycle power. This is also why they pick up EMI/RFI. Alekz’ ideas are good. These would help a great deal.
As a practical matter, and to Tboooe’s question, this will not hurt the sound; if noise was there anyway, a transformer should not make it worse unless it is placed where it can pick up additional noise.
birddogthecat said: Given that an SUT is functioning to step-up mv’s and the question is about step-down the quality of the transformer, build architecture, connecting wires(crystal Cu, Ag, Au) all impact sound.
Fascinating. Once again, nothing is simple.