Burl Audio B1 - B1D Mic Pre by gainstages
I've owned a pair of these for a while now, and have used them on both acoustic and electric guitars, and in various positions with a drum kit.
These preamps are fantastic! If you are looking for something with some character, and isn't just a Neve or API knockoff, this is a great place to look.
The sound is big, thick, and bold - making it a great choice for electric guitar, bass, and drums. That said, it can still clean up enough to handle more delicate duties like acoustic guitar.
A lot of flexibility is built into a tiny package - pad, impedance, polarity, input and output gain, etc.
Using the LEVEL control for most of your volume will give you a cleaner sound that is still big and beautiful.
Using the GAIN control is where you can really get colorful. Push your levels so that the input indicator light is getting into the yellow and you'll be rewarded with some fat saturation - giving you some soft clipping/compression, and making the sound bigger and more aggressive. Expect frequencies below 60-65 hz to have a bit more umph and 4khz and up will also have a bit of a boost.
This preamp seems to "play nice" with every mic in my locker, and offers a ton of character in a tiny package. The fact that it cleans up a little keeps it very versatile.
It's an expensive preamp, coming in at nearly twice the cost of some popular units, but the big, beautiful sound is invaluable for tracking electric guitars. Even if you don't track guitars, this is the type of preamp that any studio could benefit from - offering a different flavor for cooking up some awesome music!