The Guide to Buying an Audio Controller or a Preamplifier

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The Complete Guide to Buying an Audio Controller or a Preamplifier

Recording studios have a lot of expensive equipment in them, and when the average person starts rattling off the various types, they name microphones, speakers, and recording devices. Yet one of the most integral parts is rarely listed. Amplifiers may make the cut, yet the preamplifiers, or simply preamps, are often missed. Many input devices, such as microphones, turntables, and even some instruments, plug into a preamp, and the signals are amplified before going to the next link in the chain, which is typically the loudspeakers, a monitor, a mixer, or a recording interface.

Furthermore, preamplifiers boost signal strength, allowing it to function as an audio interface. These devices are extremely useful to those who want more control when mixing or need a little more juice from a particular instrument. Customers should have a basic understanding of the many uses for preamps and their relationship with mixers and audio interfaces. Before buying a preamp, shoppers should learn about the various circuit designs and functions of preamps to choose the one best suited for them.

About Preamps

The most basic function of any preamp is to convert a low level signal from an input device and boost it. Preamps are designed to increase voltage with as little jump in current as possible. Preamps are marketed as free-standing units or can be built into mixers and other audio interfaces. All high-end recording studios have at least one, if not multiple, stand-alone preamps to accommodate different input devices. The audio quality produced from preamps varies between the different styles of preamps. Differing circuitry systems and hybridised models have a profound effect on how preamps manipulate sounds.

About Mixers and Audio Interfaces

Once signals are transmitted from an input device, a preamp is typically the first stop in the audio chain. After the preamp increases the signal strength, the signal then travels to a mixer, audio interface, or sometimes a loudspeaker. Mixers manipulate raw sounds and blend them to a certain desired effect. Audio interfaces record sounds and allow for later playback. Several manufacturers produce all-in-one machines with mixers and audio interfaces in an already integrated preamp. However, even with the best models, preamp quality is sacrificed in order to make them affordable, which is one more reason serious recording studios prefer free-standing preamps.

Types of Preamps

Preamps typically are classified as solid state or tube amps, but there are other designs available. Tube preamps rely on tubes to create various levels of distortion, and like all preamps, they create gain. Solid state amps are the second incarnation of amps, but instead of using distortion to create different sounds, their function is to reduce distortion for a clearer, true sound. Modelling preamps use the solid state system and are incredibly versatile. They are designed to create a variety of sounds and imitate other types of preamps.

Digital preamps are also hybrid devices since they allow for digital and analogue inputs. Instrument-specific amps are designed to accommodate certain instruments. Before the introduction of these amps, all models were built to accommodate microphones first and then a musical instrument. Channel strips are often referred to as preamps, but channel strips are also found in equalisers and other professional audio equipment. The following sections offer an overview of several types of preamps.


Tube preamps are used for their warm body, depth, and ability to create pleasing distortions. They have thermionic valves to increase gain. The signal is passed through the preamps, which harmoniously blends tones of a perfect octave for "fat" or "rich" sounds. Distortions such as these are often referred to as "colour". The shape of the preamp’s tubes is designed to round out high-pitched frequencies, which aids these models in creating auditory masterpieces. Although not the most efficient type of preamp, tube preamps are considered vintage or "musical" by audiophiles, which is why they are still used today.

Solid State

Solid state amps use op-amps, often called transistors, to increase gain. They are the next generation of amps after tube models. While all amps create distortion, one huge benefit for updating to a solid state amp is that the device produces extremely low distortions even when approaching its limits. Therefore, users get a much clearer and truer sound with a solid state. This ability to create a sound with no to low distortion is referred to as "transparent".


Modelling preamps are a sort of hybrid amp. While they utilise solid state circuitry, instead of a transparent sound, modelling preamps have the ability to digitally add colour or warmth to the sound. Modelling preamps are such versatile machines, and they are designed to replicate the sound of other preamps, including but not limited to solid states, tubes, and channel strips. However, some users prefer to use the specific preamp instead of mimicking it in order to create a more authentic sound. Naturally, because modelling preamps can replace the need for other types of preamps, customers should expect to spend a little more.


Users who have both digital and analogue devices need a preamp that can accommodate both. Instead of buying two preamps, a digital preamp is designed specifically to allow users to have both analogue and digital inputs for this single device. Some preamps are marketed as digital right out of the box, but other solid state amps allow for a digital output card to be installed later. Many digital preamps are often sold as audio interfaces with a preamp built in.


While the first preamps were designed with microphones as the primary input device, some manufacturers began experimenting with amps made for particular instruments. There are many preamps available for specifically guitars, basses, and even drums. Instrument-specific preamps are used in high-end professional recording studios to capture and manipulate sound quality.

Channel Strips

Much like an extension cord, channel strips are useful because they allow for multiple input devices to plug in. Any preamp with other signal-processing circuits is often referred to as a channel strip. Although the terms preamp and channel strip are sometimes used interchangeably, not all channel strips are preamps. Channel strips are generally built into preamps, equalisers, and compressors. They are favoured for their convenience factor. Selecting the best preamp involves knowing how many input devices to accommodate.

The selection of available preamps does not have to be intimidating. Shoppers must remember each one's key features. To help them, the chart below summarises the various types of preamps and highlights the main features of each.



Solid State

Relies on transistors to increase gain; low distortion allows for more "transparent" sound


Utilises its natural compression feature; creates "warm" sounds


Built similarly to solid state amps; can mimic the sounds of many other types of amps


Has inputs for both digital and analogue devices


Designed for certain types of instruments to allow full control on colour and transparency

Channel Strip

Refers to any device, not just a preamp, with multiple signal processing circuits

Not all preamps work well with specific types of recordings, such as vocals or acoustic guitars. Other types like the modelling or digital preamp are hybridised for versatility. Understanding the basic difference of each type of preamp allows sellers to choose one that fills their needs.

Buying a Preamp on eBay

Preamps can make a significant improvement in recording quality, so when searching through all the listings on eBay, it is important to have several makes and models in mind. Include keywords to limit the scope of your search and learn more useful information on the Search Tips page.

Refine Your Search

Once you have your initial search results, there are several ways to refine your search. Underneath the search bar, eBay lists several related searches. You can click on any of those links to narrow the focus. Sometimes, too many keywords can hurt your search. If your search produces no results, remove some keywords and use filters instead. If you want a certain brand of preamp, instead of searching for "Yamaha solid state preamp", expand your search to "Yamaha preamp". You can also filter results based on category, price, buying format, and other options.

Know Your Seller

Equally as important as thoroughly researching auctions items, you should also take a moment to get to know your seller. At the very least, look at the seller’s approval rating and feedback history; only buy from sellers with a high rating and positive feedback. Buy with confidence from an ID verified seller. eBay hires a third party to crosscheck sellers’ personal information with business databases.


Preamps are essential pieces of recording equipment, and studios should have one regardless if either the mixer or audio interface has one built in. Preamps integrated into other systems can never measure up to stand-alone units. Choosing a free-standing unit allows users more control and possibilities when mixing and recording. Tube preamps are designed to create "warm" sounds, and they are designed to increase gain. Moreover, buyers in the market for a preamp that records or outputs the signal from the input device should consider a solid state amp.

Modelling preamps are the jack-of-all-trade option. They have the ability to replicate different sounds of other preamps from its interface. Digital preamps allow for analogue and digital devices to share the same equipment. Serious setups designed to record bass, guitar, and drums should check into instrument-specific preamps. Finding the right preamp does not have to be complicated. As long as buyers know what effects they want to achieve and the differences between the various types, they can purchase with confidence.

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