Some external preamps simply provide pure, uncolored sound at any gain level, useful for purist recordings. Lower noise : Many modern interfaces have low noise preamps. Beware : Specifications can be deceiving. Manufacturers typically claim a preamp noise floor of around dBu. This is excellent, but only if that noise floor remains constant at all gain settings.
Dedicated preamps typically have better specifications at their extreme settings than USB-powered preamps in inexpensive interfaces. Design Quality : Since preamps do so much heavy lifting, each component, from the specific electronic components to the power supply design and shielding affect the audio quality. Inexpensive interfaces with preamps necessitate inexpensive components, while external preamps can provide higher quality parts and designs, usually with a considerable increase in price.
Compression : Not the least important, but often overlooked feature of an external preamp, is the ability to run the preamp into an analog compressor and maybe an EQ before hitting your A-D converter. This signal path adds color, saturation, and dynamic control in the analog domain before you capture it as a digital signal. Interface preamps rarely provide an analog insert point for patching in a compressor during recording.
Cost Considerations A typical external mic preamp contains high-quality components, a well-built power supply, a durable enclosure, and quality switches, and connectors. That price includes preamps, instrument inputs, a headphone amp, monitor control, A-D and D-A conversion, and packaging.
That means the preamp itself probably uses only a few dollars in parts. Preamps in interfaces, therefore, are designed to provide relatively clean and quiet gain for not-so-difficult recording applications. While those preamps function pretty well, it should be easy to see the quality improvements that an external preamp will provide. A preamp has to have inputs. Usually, they provide both XLR connectors for microphones and TRS for line inputs and instruments such as guitars and basses.
If you use a line input or mic input for a passive instrument, the instrument may sound distorted, have a strange frequency response, or simply be too quiet. Line inputs are used to connect line-level gear that do not need additional amplification, such as high output synths or guitar processors. If your interface has line inputs, check the manual to see if these inputs bypass the mic preamp.
If they do, hooray! You can use external preamps with your interface. The most important function of a preamp is the gain. As previously mentioned, the main point of a preamp is to bring a very quiet audio signal up to the full operating level. The quality of the mic preamp is most obvious at high gain settings. Once you go above dB of gain, cheap preamps start sounding more and more lifeless, and the noise level may also increase.
Phantom power P48 is required by condenser mics. External preamps use volt wall power to easily create phantom power. The phase reverse switch is used to reverse the polarity of the signal.
An example is recording a snare drum with 2 mics, one from the top and one from the bottom. The mics are basically facing each other, so when the snare drum is hit, the bottom microphone sees the drum head moving towards it, whilst the top microphone sees it moving away from it. If you flip the phase switch on the bottom mic, the signal from both microphones will combine correctly, giving you a full, natural sound. Some preamps provide a high pass low cut filter. This circuit removes low frequencies while allowing everything above them to pass roughly unharmed.
Cutting these low frequencies is the most common way to remove rumble and unnecessary sub-bass frequencies. The pad switch is used to lower a very loud microphone signal before it has a chance to overload the mic preamp circuit. Pads typically bring the lowest gain setting of a mic preamp down to 0dB of gain. Beware that pads may slightly affect the sound of some microphones.
Types of Preamp Circuits An important difference between various preamps is their tone. Tube preamps These use vacuum tubes to boost the input signal. Solid-state Preamps These preamps use transistors or opamps to amplify a signal. Hybrid preamps …combine the best of both worlds, usually employing solid-state components at the input stage, and tube components are the output stage.
Which type of preamp should I use for my recordings? The different preamp setups vary in price and performance. The most important part of a preamp is not how clean it is, however. More than anything, you are looking for quality. Some condenser mics come with built-in preamps, but these are generally weak sound boosters and need an extra push to make it up to the average line level.
This tool is ideal for those who only want to record with a microphone and computer. These tools help bring the recorded sound from the microphone to the computer or amplifiers. Audio interfaces and mixing boards almost always have preamps built into them. The most expensive and intensive preamps on the market come in separate setups created for high-end recording. You can either buy a manufactured preamp set up or invest in several different colored preamps for a greater variety.
Many professional music recording artists custom make their preamp set up with several different settings. Your condenser microphone and audio interface will connect and record perfectly well. However, if you want to start experimenting with various sounds, I recommend the PreSonus Preamplifier as a starting point.
A condenser mic needs a preamp to bring its volume up to line level and to provide the phantom power required for the mic to work. Blue Snowball is a fantastic microphone that records crystal-clear audio. But no microphone sounds excellent if all you get from it is static noise.
Better sound quality: This becomes most evident at higher gain settings. High quality external preamps are equipped with more sophisticated circuitry that retains full transparency even at their highest gain settings.
More gain: The built-in preamps of an audio interface rarely offer more than 60 dB gain, often less. Low output dynamic mics, such as ribbons, may require up to 70 dB, sometimes even more. A special sound character: This is perhaps the most common reason to buy an external preamp.
The built-in preamps of audio interfaces usually sound fairly clean and transparent, but if you fancy a special flavor, e. Additional features: The built-in preamps of audio interfaces usually come with a basic feature set, but often lack some of the more sophisticated features you typically find on an external preamp, such as phase reverse, low cut or pad switches. Top 5 Reasons Mic Preamps Matter. A Clean Front End At its most basic, a mic preamp takes the low output from a microphone and amplifies the signal to a higher line level.
Transparency It sounds obvious, but in most cases, the ultimate goal of a good preamp should be to capture the sound as transparently as possible.
The API L preamp is legendary for its detail and warmth, enhancing anything that runs through it. Pick Your Color Do you want your track to sound warm or cool? Consistency As you become increasingly familiar with the sound and characteristics of any given mic preamp, you will begin to get a feel for which particular combinations of microphone and preamp can yield the best results for specific applications. Mentioned UA Gear. Read More.
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