I'm quite confused regarding the effect of output transformerless and transformer coupled tube amps on the sound quality. Maybe someone can explain a few points for me: 1) For driving high impedance headphones, I've heard people mention that output transformerless tube amps are better than transformer coupled ones. Is this because the addition of a transformer to the circuit adds to degradation of the sound quality? 2) Doesn't a high impedance amplifier result in a lower damping factor? So is it possible to use a transformer coupled tube amp at low impedance settings to drive high impedance headphones (will the voltage be sufficient?). This would then result in a higher damping factor and therefore superior SQ compared to OTLs. 3) Or is the whole point of tube amps to decrease the damping factor via high impedance? If this is the case won't a solid state amp with high output impedance give the same effect?