Musical Fidelity has one of those tube buffers
Audiophile grade passive impedance buffer
Preamp balanced output impedance at 20Hz measured by Stereophile as 6.9k ohms! No problem into 90k ohm balanced input impedance of old amp, but new amp inputs only 10k ohms balanced. If an audiophile grade passive impedance buffer exists on the market, I haven't seen it. Will I need to run single-ended and thereby abandon a fully-balanced setup? Or does one of my components simply need to go?