SB2 Assembly Guide

Safety Precautions, Warranty, and Disclaimer Improper soldering and handling of electricity can cause serious injury and damage to your property. Read and understand the instructions below before beginning your project. Follow the instructions, build carefully, and use the appropriate tools. Build at your own risk. DIY Recording Equipment, LLC is not responsible for any damage or injury resulting from the assembly or use of your kit. You are the manufacturer of your kit. It is your responsibility to turn this group of parts into a working piece of recording equipment. DIY Recording Equipment, LLC does not guarantee the success of your project and disclaims any Implied Warranty of Merchantability. Please visit the support forum for assembly support.
Damaged or Missing Parts All kits and parts are checked before being shipped to you. If something arrives damaged or if your kit is missing a part, please open a support ticket to inquire about a replacement. Missing parts will be replaced at our expense. Damaged parts should be returned for verification. If the part shows signs of use beyond what was necessary to determine that it was damaged, DIY Recording Equipment, LLC reserves the right not to replace the part.

Thank you for purchasing an SB2 kit! Depending on your level of experience, you should be able to turn the pile of parts in front of you into a working piece of recording gear in about 30 minutes.

If this is your first DIY project ever, we recommend reading our Getting Started Guide before, well, getting started.

If you have any questions please don't hesitate to contact us for support.

Contents :

Assembling the SB2
    1. Gather Necessary Tools
    2. Idenfity Parts
    3. Bend and Solder Resistors
    4. Place and Solder R5 and R6
    5. Place R1 and R2
    6. Place R3 and R4
    7. Bend and Solder the Bus Resistors
    8. Trim Excess Leads
    9. Solder the XLR Jacks
    10. Solder D-Sub Jack
    11. Screw on the Output Panel
    12. Slide Assembly into Case
    13. Fasten the Input Panel
    14. Screw Panels to Case
    15. Tighten D-Sub Standoffs
    16. Apply Foam Pad

Using the SB2

    Assembling the SB2

    1. Gather Necessary Tools

    To successfully build the SB2, you'll need the following tools:

    • Soldering iron (and solder)
    • Wire cutter
    • Phillips head screw driver
    • Needle-nose pliers

    If you don't have some of these tools, check out our Recommended Tools page.

    2. Identify Parts
    • SB2 Case
    • Foam Pad
    • SB2 PCB
    • Front and back panels
    • Input D-sub connector
    • Output XLR jacks (2x)
    • 10k bus resistors (4x)
    • 150 resistors (2x)
    • Screws (15x)
    3. Bend and Solder Resistors

    Bend the leads of the two 150R resistors near the body to make it easy to insert them into the PCB.

    4. Place and Solder R5 and R6

    Place the resistors with bent leads into the pads marked "R5 / 150R" and "R6 / 150R." Bend the leads against the bottom of the PCB to keep the resistors in place. Solder the resistors to the PCB. Here are a couple good soldering practices to observe:

    • Heat the pad and lead together for 2-3 seconds before applying solder
    • Apply just enough solder to cover the entirety of the pad, so that no gold is showing through
    • Leave the iron in place while you are adding solder and for 1-2 seconds after
    • The entire soldering process should take 5-8 seconds
    • Allow the solder joint to cool for about 20 seconds before soldering another lead of the same component
    5. Place R1 and R2

    Note: These are not regular resistors! They are an integrated array of 8 resistors that sum down to one pin. As such, they need to be placed in a certain direction or they won't work. And they're a pain to remove if you get it wrong!

    Locate the dot printed on one end of each of the 10k bus resistors and the square pads on the R1 and R2 footprints. Place bus resistors in the R1 and R2 positions with the dots aligned with the square pads.

    6. Place R3 and R4

    Locate the square pads of R3 and R4--note that they're on the opposite side of the footprint from R1 and R2. Place the remaining bus resistors, making sure to line up the dots on the bodies with the square pads.

    7. Bend and Solder the Bus Resistors

    Using your fingers or a screw driver, bend a couple pins of each bus resistor against the PCB to keep them in place. Double check the orientation of the resistors. Then flip the PCB over and solder the bus resistors.

    8. Trim Excess Leads

    Trim away the excess leads of R1-R6 with a wire cutter. Cut each lead as close to the solder joint as possible without compromising the joints themselves.

    9. Solder the XLR Jacks

    Place the XLRs jack in the "J2 / OUTPUT 1" and "J3/ OUTPUT 2" positions on the PCB. Lay the jacks on their backs with the PCB lying on top of them to solder.

    Solder the three metal pins of the XLR jack. Don't solder the two plastic mounting pins.

    10. Solder D-Sub Jack

    Place the D-sub jack in the "J1 / INPUTS 1-16" position. Solder all 50 pins of the connector, alternating between rows to prevent over-heating any one area. It's not necessary to solder the four mounting brackets.

    11. Screw on the Output Panel

    Attach the output panel to the XLR jacks via four of the included mounting screws.

    12. Slide Assembly into Case

    Slide the assembled PCB into the lower channel in the chassis. The XLR panel should be on the side of the case nearest the "2" in "SB2."

    13. Fasten the Input Panel

    Unscrew the mounting standoffs from the D-sub connector. Then use them to mount the input panel to the connector, keeping the standoffs only finger-tight for now.

    14. Screw Panels to Case

    Screw in the eight remaining mounting screws. Since these screws are cutting their own threads in the aluminum, you'll feel a healthy amount of resistance the first time you put them in.

    It's a good idea to install all four screws on one panel loosely before tightening each one.

    15. Tighten D-Sub Standoffs

    Tighten the D-sub standoffs against the panel with needle-nose pliers or a wrench.

    16. Apply Foam Pad

    Remove the backing and apply the neoprene foam to the bottom of the case.

    Complete!

    Congratulations on Completing your SB2!

    If you had any difficulties or suggestions for improving this guide, please drop us a line.

    Using the L2P

    Operation

    The SB2 is a 8- or 16-input, stereo output, balanced, passive summing mixer. It has two primary applications in the studio:

    • Place it after colored mic preamps set on the -10 setting to drive the preamps harder without clipping converters
    • Place it between line outputs and and mic inputs on the -30 setting to add preamp color to tracks during mixing
    Input

    The SB2 accepts 8 or 16 balanced inputs via 25-pin D-subminiature (DB25) jacks. You can operate the SB2 as an 8x2 summing mixer by using only inputs 1-8 or as a 16x2 by using both input jacks. The DB25 jacks are wired according to the TASCAM 8-Channel Balanced standard.

    The odd-numbered channels are summed to the left (1) output and even channels to the right (2) output. You can sum an entire mix by creating 8 stereo busses in your DAW or mixer and sending these to the SB2.

    Output

    The summed signals exit the SB2 via two 3-pin XLR jacks. The outputs should be amplified back to line level with a pair of microphone preamps.