Preamplifiers: for a brilliant sound performance in your rehearsal room and on stage

Do you want to record your songs at home or is your band planning a live performance? Do you need (just admit it: you want!) new equipment? Some musicians are convinced that a good setup cannot exist without a preamplifier. However, what are they capable of? And: do you need an external preamplifier to achieve a good sound or is it sufficient to have an audio interface ? This page will provide the guidance you need: come and find out what microphone preamplifiers and headphone preamplifiers are really capable of and what you should consider when purchasing one. It also includes the most important technical background knowledge and our suitable product range.

• Microphone preamplifiers from IMG STAGELINE

• Microphone preamplifiers with low-noise filter from IMG STAGELINE

• Headphone amplifiers from IMG STAGELINE

• When do I need a headphone amplifier?

• What exactly does a microphone preamplifier do?

• Why is it worth it to use a microphone preamplifier?

• These features indicate a high-quality microphone preamplifier

At the beginning of your signal chain, you usually find a microphone. It transforms the sound of your voice or your instrument into voltage. However, the voltage created by a microphone is very low. Thus, you need to amplify the output signal, usually by about 30 to 60 dB. Only then, it is possible for the A/D converter to further process the signal from your interface or other equipment. You will find out that there is no alternative to signal amplification if you want a good sound reproduction. Tools such as microphone preamplifiers or preamps can easily achieve results: they provide a more powerful audio signal and a detailed sound without distortions.

A good microphone preamplifier should give you a clear quality boost at home recordings and stage performances. This does not only include a lot of gain, but mainly an interference-free sound with a great level of detail. Some preamplifiers are equipped with useful features which additionally enhance the sound quality. This also includes the low-noise filter.

Low-frequency interference could, for example, be impact noise which transfers from the stand to the microphone, It can also rumble on stage or you can have guitar chords which are humming too much in the low frequencies. For this purpose, preamplifiers such as our MPA-102 or MPA-202 are equipped with a variable low-cut feature: simply switch it on and your preamplifier cuts interfering signals below 100 Hz.

Are you mixing your own tracks in a home studio or are you working mobile as a DJ? Then it could be worth it to invest into a headphone amplifier. Maybe, you are asking yourself why you need external preamplifiers if you have got high-quality headphones which can be turned up to a high volume level? This is simply because you achieve a better sound with microphone preamplifiers. In short, audio signals require a certain electric performance for the transmission between replay source and headphones. The sound quality suffers if the power capability is too low.

Particularly high-quality headphones are hungry for power: with a low voltage, they provide a sound which is not loud enough and this would prevent them to deliver their full potential. Preamplifiers with a high power capability get the most from your headphones: they deliver a dynamic sound which is crystal-clear and allow for fine sound details from the track to be audible again. This difference in quality may help you a great deal, e.g. when mixing in your home studio. Another advantage: preamplifiers, e.g. our PPA-4 are equipped with additional inputs for operating up to 4 headphones simultaneously.

• you need an additionalheadphone output,

• the volume level of your headphones cannot be turned uphigh enough,

• you are using high-quality headphones with a high resistance (impedance) in the studio or

• you want to enjoy your home music at the next level.

A microphone preamplifier is an electric circuit which can be used to enhance a weak signal voltage at the output of your microphone to a respectable value. The microphone signal is usually available in a very low voltage range between 0.001 and 0.01 V. This voltage is also called mic level. This has to be brought up to line level if you want to process the original signal of other equipment. This is approximately 1 V, i.e. it is 1,000 times stronger than the microphone signal.

Thus, it is ideal if you boost the signal of your microphone as early as possible. Each microphone creates background noise (even though it is quiet with high-quality microphones). Possible interference [Link: www.img-stageline.de/magazin/brummschleife] may increase with any additional device the audio signal passes through on the way to the PA speaker. A microphone preamplifier can easily correct this disadvantage. It already boosts your microphone’s signal to a high level at the start of the signal chain which makes it less susceptible to interference. A preamplifier does not amplify interference which accompanies a signal along the signal chain.

Some recording interfaces already feature a built-in preamplifier. Have you just equipped your first rehearsal room with a small setup? At the beginning, it is okay to start with the built-in preamplifier of an interface. Many musicians only decide later on to get a preamplifier in order to enhance the sound of their home studio or live performance. There may be some reasons for that:

• More gain: built-in microphone preamplifiers of the audio interfaces rarely provide a gain of more than 40-50 dB. With high-quality interfaces, it may be up to 60 dB. However, this standard may quickly reach its limit during many applications: dynamic microphones with a low sensitivity (this also includes ribbon microphones) often require more gain (like 70 dB) to deliver a full and transparent sound. With a preamplifier, e.g. our MPA-102 your microphones can deliver a powerful sound performance rich in detail.

• High-quality sound: the difference in quality can especially be heard with higher gain settings. High-quality preamplifiers still ensure full sound transparency even at a high power level. Meanwhile, basic models only deliver a mat and indistinct sound with a gain above 50 dB. Microphone preamplifiers can thus add the final touch to your performance. Particularly, if you pick up soft instruments or work with microphones which require a lot of gain. In this case, please also pay attention to gain staging.

• Additional features: high-quality models are often additionally equipped with relevant features for the sound equipment. This may include, e.g. a phase reverse switch, phantom power which can be activated as required or a low-cut filter. You can read the advantages of that in the next section.  

Are you thinking about getting a new microphone preamplifier? Then you should pay attention to these basic features and additional features:

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