A quick guide to choosing a mic preamp
Isn't it weird that certain numbers can make us engineers take to our keyboards and have full blown emotional arguments? Think I'm wrong? Well... 1073 or nothing. You feel that? Yeah, I get it.
The short answer is that mic preamps fall into three broad families. Transformer balanced pres, like the Neve 1073 or API 512, add weight and harmonics. Transformerless pres, like Grace Design or GML, stay clean and transparent. Valve pres, like the Manley Force, add warmth and a gentle, compression-like character. The right choice starts with the records you love and what you record.
What are the three main types of mic preamp?
Like a well balanced diet, there are some staples you should keep in mind when it comes to mic pres. Let's split them into three main categories. Transformer balanced, transformerless, and valve. There is more nuance here, but for now this will have to do.
What does a transformer do in a mic preamp?
A transformer isolates the circuit and can step voltage up, down or leave it at unity. Pushed harder, it also adds harmonics, anywhere from a subtle sheen to outright distortion.
The amount of reviews, product descriptions and videos that harp on about transformers is startling. Sadly, it's for a good reason. Transformers help to isolate a circuit, as well as provide the means for voltage to be stepped up, stepped down or left at unity. (They can do a lot more, but let's leave it there for now.) An unintended benefit of using transformers is that they also impart harmonics the harder you push them. This lets a clean source feel more surreal when used gently, or adds straight up distortion when pushed harder. Like all things audio, not all transformers are designed equally. Jensen and Lundahl make incredibly clean transformers for maximum clarity with minimal distortion. Sowter, Carnhill and Cinemag make a wide variety, from very clean to ones that saturate a little earlier.
So what are some good options to look at? Let's kick off with the API 312 and 512. Then the Neve 1073, and its LB, OPX, DPX and DPA versions. Then the Rupert Neve Designs preamps.
What is a transformerless preamp?
A transformerless preamp keeps transformers out of the signal path and chases the most accurate, uncoloured picture of the source. This is the "wire with gain" approach.
For those of you looking for cleaner, more transparent tones, this is the class to reach for. This is where the "wire with gain" tag tends to get thrown around. Some good options to check out are Cranborne Audio, Grace Design, Millennia and GML. Plenty of interfaces have fantastic clean pres built in too.
What is a valve mic preamp?
A valve preamp uses valves to bring the microphone signal up to line level, and in doing so adds harmonics and a gentle, compression-like character, especially when pushed into distortion.
These pres use valves to amplify the microphone signal up to line level, and in doing so the valves, and often the transformers in the signal path, generate some harmonics. Valves tend to impart a gentle, compression-like character to whatever you put through them, especially when the unit is pushed into distortion. The Manley Force, Chandler Limited REDD.47 and Retro Instruments PowerStrip are a few good examples.
Which mic preamp is right for you?
Start with the records you love. If your taste runs to classic, characterful productions, lean towards transformer or valve. If you love pristine, modern clarity, lean towards transformerless.
It all starts with what you enjoy listening to. If those genres line up with what you are recording, you can begin the journey. If you find yourself reaching for classic hit records, like the self-titled Fleetwood Mac record, or the world of Jack Antonoff and Sabrina Carpenter's Man's Best Friend, then the transformer balanced world will line up well with your taste. The valve pres will likely suit you too. Most recordings before the 90s fall into this camp.
If you enjoy records that are pristine and clean, like the work of Earth, Wind & Fire, you might be surprised to learn that GML mic pres are all over them. That's no accident. George Massenburg, the founder of GML, was their long-time engineer.
With valve pres it's a little harder to narrow things down so simply. They can be pristine, like an Avalon VT-737 or an A-Designs MP-2A, or they can serve up serious character, like the Chandler REDD.47 or the Universal Audio 610. Some records to keep in mind for these tones are the Beatles' early records up to 1969, and Neil Young's Harvest.
Does the preamp matter more than the microphone?
Usually not. The things that make the biggest difference, in order, are mic choice, then mic placement, then the preamp, then conversion.
These are wide guidelines, of course. Someone once told me that the things that make the biggest difference when recording go in this order. Mic choice, mic placement, pre, then conversion. Alter either of the first two and the change in tone is usually far more significant than simply swapping the pre.
Which mic preamp suits which instrument?
Neve and API pres suit drums and acoustic sources. Clean pres suit classical and voiceover. Valve pres suit stacked vocals and guitars.
Certain pres just play better with certain instruments. Neve and API pres play well with drums and acoustic sources. The APIs feel a little faster and let transients come through, and the design pushes the midrange more in your face, even when levels are matched perfectly. The Neve 1073s also sit nicely with drums, vocals and acoustic instruments because of the way they soften the transients slightly and make them feel a touch more compressed.
Clean pres often get used for classical recordings or voiceover, as they stay as accurate as possible while still making the listener feel like they are in the space where the performance was captured.
Valve pres are always a good shout when you are stacking vocals and guitars, as their tone lets things blend together almost seamlessly while still keeping an airy quality.
Like all things audio, most of this is subjective and needs some research on your part. Check out your favourite records and find out what they used. Chat to your favourite producers and engineers and ask what they enjoy. Perhaps most importantly, experiment with your tones. Try different plugin emulations as a starting point, then make the leap into the analog world.
Frequently asked questions
What is the most famous mic preamp?
The Neve 1073 is probably the most revered, prized for its weighty low-mids and musical character. It turns up on countless classic and modern records across drums, vocals and acoustic instruments.
What is the difference between a transformer and a transformerless preamp?
A transformer based preamp adds colour and harmonics, more so as you push it. A transformerless preamp keeps the signal as clean and accurate as possible. One flatters the source, the other reports it faithfully.
Are valve preamps good for vocals?
They can be a lovely choice, especially when stacking vocals and guitars, as their tone helps parts blend while keeping an airy quality. Whether they suit you depends on the voice and the record you are chasing.
Do you need an expensive preamp, or are interface preamps good enough?
Plenty of interfaces have genuinely good clean pres, and they are a fine place to start. A dedicated preamp earns its place when you want a specific character or are chasing a particular classic sound.
If you ever need any advice or guidance on recording, recording equipment or production, feel free to get in touch.
Alec Brits
alec@studiocare.com