The difference depends on the impedance and sensitivity of the headphones you’re driving. For higher impedance and/or lower sensitivity headphones, like Sennheiser 600/650/800/800S for example, the Red will be substantially better. But for much easier to drive headphones like Sennheiser 5xx series, the differences will be marginal. Hope that helps. For most planars, since they almost always require more power than similar impedance dynamics, even if they have low impedance, the Red is usually going to sound much better.