600 ohm headphone amplifiers
prices on 22 models— amplifiers for which the maximum allowable headphone impedance is at least 600 ohms.
600 ohms is the highest impedance value commonly found in professional high-resistance headphones (higher impedances are much rarer). These headphones have a very clear sound, but they are also very demanding on the signal strength. Therefore, for their normal operation, it is necessary to use only amplifiers where the possibility of such an application was originally provided — that is, models from this category. This is due, among other things, to the fact that without sufficient power, the sound from high-impedance headphones will not only be too quiet, but also not of very high quality — a weak signal can lead to frequency response distortion. At the same time, this type of amplifier, usually, is quite capable of working with lower impedances — 300 ohms (see the relevant paragraph), 150 ohms, and even with low-impedance headphones.