Gkit Baby Pre Assembly Manual

Assembly Guide

“Baby Pre”v4.1

Designed by:

Robert-Eric & Peter Gaskell

December 2016

Assembly Guide

Thank you for your interest in the GKit BabyPre. The BabyPre kit is not only a way to
get an excellent 2-channel mic pre at a very reasonable price, it is also an educational
resource that can help you learn about fundamental analog circuits. One can choose
to simply build the kit and start using the mic pres right away or the kit can be used to
study useful electronics concepts that will help in understanding this and other audio
circuits.

contains all the information you need to build, test, and troubleshoot your BabyPre.
Significantly more detail is provided in the complete manual. If you are new to
electronics, we recommend that you read chapter one of the complete manual before
starting your assembly. You can find this manual and additional information about the
project on the GKL website at:

www.gklaudio.com/gkit-babypre

Visit our site for:

• Complete Manual

• Schematics

• Laboratory Exercises

• Educational Information

• BOM (Bill of Materials)

• Videos

• Optional Parts and

Add-on Kits

Tools

Required Tools

To assemble the GKit BabyPre, you will require:

• Soldering Iron

• Fine Electronic Snips

• Solder

• #1 Phillips Screwdriver

We recommend that you also have:

• Solder Sucker

• Multi-meter

• Needle-nose pliers

Before You Start

There are a couple important details to note before you start. First, you MUST solder
the additional wire shown in Figure 7 between the power input and test point 5 (TP5)
or your circuit will not work. Second, be sure to NOT populate test points 6 and 7
(TP6 & TP7) until after testing the power supply. This is describe in the "Testing"
section of this guide.

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The Board

Your BabyPre’s circuit board has been carefully laid out to make assembly and
trouble shooting as easy as possible. There is no required harness wiring; all the
components solder directly to the board. All of the parts have been labelled outside
the component footprint so part numbers can be identified after the component has
been populated. The board has both a top and bottom silk screen so signals can be
easily traced through the circuit.

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• Every board is labelled with its version number. This guide is for board version v4.1.
If you have a different board revision, check at gklaudio.com for information specific to
your run of boards.

• The BabyPre has two identical channels so many of the components appear twice
on the board (e.g. R4_1 and R4_2). Components in the PSU and Phantom Supply
are not duplicated.

• Not all components get populated, these components are labelled “opt” for “optional”.
The purpose of these optional components is described in the Complete Manual.

• You can write you name on the board's top/left corner.

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Components

The components for the GKit BabyPre have been carefully bagged and labelled to
make assembly as simple as possible. We recommend you populate the components
in order of the bag #s. Start with the resistors and move on to the taller components.

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Regulator heat-sink

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!"#$%&'N)'Be certain to add the extra wire between the positive (+) transformer

input jack (J1) and TP5. The wire should connect where the solid black line is

shown in the picture above.

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