Warm Audio's TB12 Tone Beast mic preamp is really multiple preamps in one. The 2 different Op Amps and 2 different output transformers are available at the flip of a switch. These differences in Op Amps really show when you push the preamp to the limits while the change in transformers from the 100% Steel to 50% Nickel will change from a colored sound to less color but more low and high end. You can also source other Op Amps and swap them out yourself for even more tonal options however Warm Audio warns "Beware that Warm Audio may not be able to warranty a unit that has been opened and tinkered with" so be careful. I would highly recommend this for both home and professional studio use.