Can preamp drive headphones?
Preamps are excellent tools for enhancing recordings’ audio quality. Before it enters the recording software, they prepare the signal from a microphone or instrument. Headphones cannot be driven by preamps. A pair of headphones cannot be driven by the current offered by a preamp’s outputs. This is mostly caused by the preamp’s high output impedance compared to the headphones’ input impedance. Impedance plays a key role in this situation.
We must define impedance and explain why it is crucial in order to comprehend why it is bad practice to use a preamp to drive headphones. The audio signal would be seriously weakened if you tried utilizing headphones with a preamp, which would lower the sound quality. Alternatives do exist, though, and we will go over all the pertinent details in this post.
Why A Preamp Can’t Drive Headphones?
Impedance is the primary cause of a preamp’s inability to correctly drive headphones, as I previously stated. This is a reference to how any electronic gadget works with an alternating current. Every single electronic device, whether it be a piece of recording equipment or a common household item, has an impedance rating and is measured in Ohms.
Technically, impedance and current are in opposition to one another at constant voltage. This means that the flowing current will be smaller when there is a high impedance and higher when there is a low impedance. Regardless of the type of amplifier—preamp, headphone amplifier, or power amplifier—output impedance will be produced.
According to this rating, the device’s receivers can handle a certain amount of current. One may assume that since a preamp generates high output impedance, it should be possible to drive relatively small equipment like headphones without any issues. A preamp really produces an audio signal out of a relatively modest current due to its greater output impedance. On the other hand, a headphone amplifier is better suited to powering them due to its low output impedance.
Preamp inputs have what is referred to as input impedance in addition to output impedance. Speakers and headphones both have input impedance. Input impedance determines how much current is drawn from the linked device, which makes it different from output impedance.