2. Why do I need a preamp?

Usually, at the beginning of a typical recording setup, you have a microphone that captures your instrument or voice and converts the sound event into an electrical voltage. However, microphones generally produce very low signal levels. This is a problem because every additional signal processor in the chain inevitably adds noise to the signal. To keep the influence of these noise sources as low as possible, you need to amplify the signal as early as possible in the signal chain to achieve an acceptable signal-to-noise ratio for high-quality recordings. That's precisely the role of a preamp or microphone preamplifier. Since it's crucial for signal quality to bring the signal to a level (line level) that's immune to interference and noise as early as possible, the preamp plays a significant role. After the artistic performance, considering the room acoustics and the recording microphone, the quality of the preamps determines how the signal can be further processed. So, you should pay special attention to the quality of the preamps.

Do I need an extra device?

Now, every mixer and many audio interfaces already have their own microphone preamps. Can't we just use those? Why would I need an external preamp or even a channel strip?

Firstly, there's nothing wrong with using the microphone inputs on your mixer or audio interface. They do the job quite well, even very well in some cases. However, there are still reasons to consider using an external preamp or channel strip. Since the preamps in such devices are just one aspect, they aren't the main focus during the design process. The circuit design is often just standard. This mainly affects the available gain. Such microphone preamps often provide no more than 40 to 50 dB of gain, although better mixers and audio interfaces can offer up to 60 dB. However, for many applications, this isn't enough, especially when you're working with a ribbon microphone or with quiet instruments.

In general, remember that your recording is only as good as the weakest link in the recording chain. So, if you're using high-quality microphones, you should also amplify their sound advantage or characteristic with a high-quality preamp or channel strip.

Another reason for using an external preamp could be the specific sonic characteristics that many of these preamps offer. This could be a generally quieter, more detailed sound or a particular sonic coloration inherent in some models. Think vintage sound. In recent years, this has become the main argument for many users, and many manufacturers have responded accordingly. You can find many preamps today based on historical circuit designs that revive the desired sonic aesthetics. Tube circuits have also come back into fashion.

A third argument in favor of external preamps is that many interfaces offer only a limited number of microphone or instrument inputs. With additional preamps, you can also utilize the line inputs.

Preamp or Channel Strip?

SPL 9844 (2-channel tube preamp in Class-A technology)

Avalon VT-737SP (1-channel channel strip in Class-A technology)

So far, we've only focused on preamps. However, there are also what we call channel strips. What's the deal with those?

A channel strip is a combination of a high-quality microphone preamp and a compressor and/or equalizer. The basic idea of the channel strip concept is to bring a channel strip of a large, high-quality studio console home. This way, you get big sound for a small price because, in most cases, you don't need more than one or two recording channels simultaneously. Channel strips are great when you want to send a "complete" sound image to the AD converter. Of course, this requires a basic idea of how you want the recording to sound in the end. This includes some experience because once the sound is on tape or hard drive, it's challenging to correct compression and EQ settings. If you're a fan of this approach, a channel strip provides excellent options.

If you're unsure about the desired end result, it's better to record the signal without additional signal processing. In this case, a high-quality preamp is sufficient.