Microphones are happy plugged into the Shinybox Si4. For a long time, I have associated "big"-sounding preamps with coloration and old-school design- transformers and discrete circuitry, running at high voltages and class-A biased. I've associated chip-based transformerless preamps with "clean", but generally small, brittle-sounding audio. These preamps have quickly changed my perspective. This cool-running, transformerless, chip-based preamp doesn't color the microphone or your source- but it lets your signal through sounding BIG, with no trace of unpleasant, etched high frequencies or lack of low-frequncy authority. It sounds deep, dimensional, and accurate- fast but smooth. You can hear the air around your sounds, with tons of detail but without exaggeration or diminishment of any range. Clearly this is a well thought-out design using high quality components implemented in an optimized fashion. It seems like it will last for forever, too- not only because it is physically so well constructed, with quality switches and pots and a nice thick face-plate, but also because it doesn't get so super hot (audio components are essentially dying a long heat-death as you use them). The internal switching power supply runs much cooler than linear designs, and there is a lot of space internally for the components to radiate heat. The circuits are well laid out, and the preamps exhibit NO noise, even at maximum gain settings. I am usually more than willing to tolerate a little noise if the equipment SOUNDS great, but this design achieves both extreme quietude and superb sound. The higher input impedance available via the front panel switches really enhances the openness of ribbons, dynamics, and some condensers (especially ones with higher output impedances). Thank you, Jon Ulrigg, for building this device. I want more channels, right away, and at this price I can actually afford them. Very stoked.