There are some of us who are happy with the fact that the sound quality is just perfect once the mic or the guitar is plugged into the preamp and then on to the amplifier and the speakers. On the other hand, some of us have a keen urge to find out how preamps actually work. Let us look at the most common types of preamps and find out how they work to boost the sound signal to line level (the level required to play the sound in standard devices.)
Solid State Preamp
This device uses transistors to boost sound. Its biggest plus point is that it produces very clear and detailed sound. There are two types of sound- transparent and colored. The latter contains distortions added to change its quality. On the other hand, a transparent sound is taken right from the source without any changes.
If you want your preamp to relay the sound without making any distortions of its own, then this type is the one for you. You can find these devices ranging from a couple of hundred dollars to several thousand dollars. Combine this with a high quality mic and you shall get superlative quality sound. You can find preamp schematics for this type on the web for free. Or, you can get in touch with any sound engineer friend of yours.
This device uses vacuum tubes to amplify the sound. Unlike solid state, this device adds color i.e. distortions to your sound. These cannot be removed at a later date. Of course, you can always add distortions later using a solid state preamp but it will not be the same thing. The change in sound quality here will be very natural and normal. This makes it a great choice for recording rock music, blues or jazz. Do not be in a hurry to set up this preamp without a look at preamp schematics because these devices can be very expensive. The last thing you want is to blow it because you did not check the preamp schematic.
Hybrid Preamp
As the name suggests, this preamp is a combination of the above mentioned types of the device. This device uses tubes as well as transistors. This helps in reducing the cost of the device without compromising on quality. However, this means that you will have to take a longer look at the preamp schematic. This device also gives you a lot of freedom to adjust the quality of the sound. However, those who want perfectly natural sound or those who want a wholly colored sound may get stuck with the hybrid device that gives them a bit of both.
A preamp can contain
• Mic input
• Mic trim or level control
• Line level output
• Phantom power circuit
• High pass filter to remove low frequency rumble from mic stand and pads
The first three are found in all preamps. The phantom power circuit supplies power to the mic instead of receiving power from the same. This can be useful under certain circumstances
The last component is not needed unless you are focusing for very high clarity with very little external interference. Amateurs do not have such high specifications and requirements. Make sure you think twice before opt and pay for this feature in the device only if you need the same.
Keep in mind that sound engineering is a very complex and dynamic field. Hence, do not be surprised if you find something about preamps that you had no idea about. You should focus on knowing all that is necessary to use the preamp properly for your requirements. Do not try to learn it all as that would be next to impossible.
