- Impedance Mismatch: Guitar amplifiers have a high impedance input, designed for the relatively low output of electric guitar pickups. Microphones, on the other hand, have a low impedance output. When you connect a low impedance source like a microphone to a high impedance input, it can result in a significant loss of signal strength and a weaker sound.
- Frequency Response: Guitar amplifiers are designed to amplify the frequency range of electric guitars, which typically falls between 80 Hz to 15 kHz. Microphones, however, cover a much wider frequency range that extends beyond the limits of guitar amplifiers. Connecting a microphone to a guitar amp may result in an uneven frequency response, with some frequencies being amplified more than others, leading to a distorted or unnatural sound.
- Overloading and Damage: Microphones produce a much lower signal level compared to electric guitars. When you connect a microphone to a guitar amp, you may need to turn up the gain to hear the signal, which can result in overloading the amp's preamp or input stage. This can cause distortion and may even damage the amplifier's components.
- Noise and Feedback: Guitar amplifiers are more prone to noise and feedback than microphone preamps designed specifically for microphones. Connecting a microphone to a guitar amp can amplify unwanted background noise and make it more susceptible to feedback, especially if the amplifier is set at a high gain.
For best results, use a microphone with a dedicated microphone preamp or mixer that has a low impedance input and the appropriate frequency response for microphones. This will provide a clean, amplified signal without the risk of damaging your equipment or compromising sound quality.