Bend the resistor leads 90 degrees at the body so they can be inserted into the PCB.

Place the resistors into their respective positions on the PCB. As you place each resistor, bend its leads against the bottom of the PCB so that it stays in place during soldering.

Solder the resistors to the PCB. Observe good soldering technique: heat the pad and lead for 2-3 seconds, apply a small bit of solder, and continue to heat the pad for another 2-3 seconds. The finished joints should be shiny and should have just enough solder to cover the pad entirely.

Use clippers to trim away the excess leads. Clip as closely as possible to the joint without clipping the joint itself.

Note that there are two different types of transistors in this bag: some with silver markings on top and some without. Those without a marking are the BC327s. Place them in the positions that have an outline of the transistor instead of a filled-in shape. Make sure the transistors are aligned so the flat edge matches that of the outline on the board. Then solder and trim.

Spread out the pins of the two LSK389 transistors so that they will fit in the T3 pads. Then place the transistors, making sure to align the tab on the body with the tab on the PCB.

Important: Double check the orientation of these transistors before soldering. These parts are expensive and difficult to remove once they're soldered in. Once you are positive that the tab on the transistor and on the PCB line up, solder and trim the leads.

These components are the functional core of the MB2. Their job is to provide 26dB gain for both the positive and negative halves of the balanced signal at the same time. This is a very delicate task, as any noise or distortion introduced in one half of the signal will not be canceled out, and will be amplified by the following mic preamp. So each LSK389 contains two matched, low-noise transistors (one for each half of the balanced signal), which are thermally coupled in the same case.

T3
LSK389 transistor (x2)

Place the smaller capacitors in their respective places. These capacitors are not polarized and therefore can be placed in either direction. Solder then trim the leads.

These capacitors are polarized, so they must be placed in a certain direction. The positive lead is slightly longer, while the negative lead is marked with a stripe on the body of the capacitor. Place the capacitors with the positive lead in the pad next to the "+" marking on the PCB. Double check their orientation, then solder and trim.

Screw the input and output panels to the XLR jacks with the longer, thread-cutting screws. Leave the screws loose for now so that the XLRs have a bit of room to move.