Gear: You have your Shure SM57, a dynamic mic. which costs about $100, your Epic 1-Eighty, a small diaphragm condenser ($60) you found in the sale bin at the local music store, and a Neumann U87 large diaphragm condenser ($3,300) which you rented on your way out out the door after the sale. And, for your preamps you’ve borrowed your uncle’s BarelyUseable YerAPRO 1202 mixer ($165).
Client: You told your uncle you needed it because you’re getting ready to record a duo with acoustic and electric guitar and one vocal; which just happens to be Sting and Dominic Miller. But, you didn’t divulge that to your uncle because, 1) he’d want to charge you rent on the mixer, 2) he’d want to be at the session to give Sting his latest demo, and 3) he’d want to “produce” them!
Last Minute Details: Just before the talent arrives, you plug everything in, test the signal, find out that one of the channels is inoperative because it’s three months old, and that Sting prefers Italian wine now that he’s living there. So you run back out, get an $8.00 bottle of Valpolicella (hoping he won’t notice), rush back, and just as they’re arriving, have everything ready.
Talented Client: Sting needs to leave ASAP to get back to his vines in Italy, so they sit and tune up. Sting sings a few lines to warm-up, Dominic plays a few Bach licks and they say they’re ready. You record-enable your DAW and they nail it in one take. Then you all listen back.
Sad Realization: As you all listen back, you’re sweating because you hear a hum and hope Sting doesn’t notice it. Then you notice how strident Sting’s vocal sound is . . . Dominic’s acoustic guitar sounds thin . . . his amp sounds small . . . you look up . . . sweat now pouring down your back all the while wishing Scotty really did exist to you beam up. Sting’s not happy and Dominic is giving you the death stare . . .
. . . all because your uncle decided to get a BarelyUseable YerAPRO 1202 mixer, and, well, I won’t mention the wine mistake. Before I explain why using a BarelyUseable mixer is a bad idea, let’s start by looking at the purpose of preamp, the different types, and some basic features preamps have.
The Preamp: what it does, types and features
What is Does:
A preamp takes a low level signal, optimizes it, and then sends it to the next stage in the audio path. Microphones have a very low level and that level needs to be increased to be useable. A preamp will do just that.
Assets of a preamp are:
- deliver a reasonable amount of gain with lots of headroom
- be as noise-free as possible
- amplify the sound with no undesirable sound artifacts
Types: Tubes, Solid State and Transformers
Vacuum Tubes, Solid State (transistors), and Transformers are components used to amplify a signal, but not all are necessarily used in one preamp. Some example configurations are: solid state with a transformer only in the output; tube-based with dual (input/output) transformers; and solid state with i/o transformers. Designers configure their preamps using a combination of tubes, transistors, and transformers based on a variety of criteria to design as good a preamp as possible.
The most basic preamp usually has a few features that, when configured, can handle most recording applications. They are:
- Gain: Increases/decreases the level from the microphone.
- Phantom Power (48 volt): Provides power for condenser microphones. Dynamics don’t need it and don’t turn it on for a ribbon mic unless the manufacture says it’s OK.
- Phase: Inverts the polarity of the input signal. This is great for drums when you want the bottom snare mic to be in phase with the top.
- Pad: Reduces the input signal by a preset dB to reduce overload. Great for drums.
- High Pass Filter: Cuts low frequency content below a preset or variable frequency. This is a great way to clean up low end noise or unneeded low end content.
- Variable Impedance: Adjusts the input impedance of the preamp to better match the microphone’s output impedance. This can “EQ” the signal in a pleasing way.
- 2 or More Channels: Instead of just one preamp, the same preamp is duplicated into a 2, 4 or 8 channel preamp. Great for on-location recording or drums.
- Solid State / Tube Blending: Adjusts to have only a solid state or tube signal, or a balance of the two.
- Compression, EQ and Filters: Typically found on the single channel ones, some preamps will have on board compression, full EQ and filters. These are known as channel strips because it’s basically like one strip from a mixing console.
It all comes down to the quality of the components, how it’s wired together, and who’s involved. It’s the difference between a preamp designed by a large audio company and made in another country by low-paid employees and using low-cost components, versus a preamp designed and built by a small domestic audio company using high quality components. That said, there are variations between boutique preamps and very low end ones, just as their are wide price variations. It’s certainly possible to find a happy medium if price and performance are serious considerations.
The Sound: What’s the sound difference between a good and bad preamp?
You may be wondering, could I even tell the difference between a high-end preamp and a low-end one? I’m confident you can. Try this sometime: if you own a cheap preamp or mixer, go rent a really high-end preamp from your local music store and try them both side by side. Record the same vocal or guitar part twice using each preamp and then listen back. You could also visit some audio forums and get users’ takes on certain preamps. Again, the descriptions will be somewhat subjective, but with a little research you’ll find that a certain preamp will be described in similar terms by various people.
So what will you hear? This is where it gets a little hard to explain and describe, and many people describe what they hear in different ways. There are a few words and phrases the pros use to describe the sound of a great preamp:
tons of headroom, pristine, 3D-quality, real, warm, fat, quiet, detail, definition, clarity, low-mid richness, thick, colored, woody, natural, rich, smooth bottom, shimmery top-end, focused mid-range.
Not every preamp is going to have all these qualities present, but a combination of some. Can you think of the antonyms of the above words? That will describe the sound quality of a bad preamp. But these are just words. Experience it for yourself and you’ll hear it.
Preamp Choices: What to buy?
There are a lot of really great preamps out there, but I’m not going to tell you what you should or shouldn’t buy. It depends on your production needs, and your budget. There’s a general rule of thumb that somewhere in the vicinity of $800 to $1000 for one channel is going to get you a great preamp. I know that for many this is still out of reach, so thankfully there are a few companies out there who are doing it for less, but keeping pro quality.
If you have a large budget, certainly look at Neve, Vintech, API, Avalon, Daking, or others in that caliber. But, if your budget is smaller, have a look at companies like Black Lion Audio, FMR Audio, Sytec Audio Systems, or Shinybox. These companies are making great preamps at exceptional prices that are just as pro as the “big boys”.
In the case of Sting and Dominic Miller, you’ve already got a great source. Having the right preamp will propel your recordings to higher altitudes fast!
Join me next time for part 5: The Microphone