Based on the API 500-series form factor, the B1 and B1D are single-channel mic preamps meant to complement the B2 Bomber ADC and the B80/B16 Mothership. Both share the same proprietary BX3 input transformer and an all-discrete, class-A, direct-coupled, capacitor-free circuit path, giving amazing punch on drums, beautiful tonality on guitars, and warmth with presence on vocals.
Both preamps come complete with Gain and Level controls. For that heavy, gainy tone, crank up the stepped gain control and offset it with the level control; for clean tone, turn the gain down and crank up the level. For ribbon mics and other low-impedance sources, use the transformer-coupled impedance select. The 1/4" instrument/line input on the front panel handles DI work, and the PAD switch takes hot signals and balanced line inputs through the mic XLR on the back panel.
B1 vs. B1D: the B1 uses a nickel-core BX2 output transformer for a cleaner, more open top end, while the B1D swaps in an all-iron BX4 output transformer for extra weight and a darker, more aggressive "rock" tone - hence the "D". Choose the B1 for warmth and clarity, or the B1D whenever a track calls for heavier iron-core saturation.
Both the B1 and B1D get the best out of any microphone, whether dynamic, condenser or ribbon. Run your primary tracks through either preamp followed by a B2 Bomber ADC and that's about all you will need for a warm, punchy, analog-flavored signal chain. Both were rigorously tested with the popular Royer R-121 in the low-impedance setting, and pair especially well with guitar amps.
B1 vs. B1D: Choosing Your Output Transformer
Both preamps share the same proprietary BX3 input transformer and discrete, class-A, direct-coupled signal path. The B1 pairs that with a nickel-core BX2 output transformer for a cleaner, more open top end. The B1D swaps in an all-iron BX4 output transformer for extra weight, massiveness and a darker, more aggressive rock tone - hence the 'D'. The B1D pairs especially well with acoustic guitars, keyboards and vocals that need more grit; run multiple B1 or B1D channels on rhythm tracks for instant glue, or use either in place of EQ and compression for true analog PHAT.
