Make: Projects
INSERT FX jacks in your Mackie 402-VLZ3 mixer
How to add two INSERT ¼" phone jacks to this mixer mic channels and allow plugging audio effects (compressors, limiters, delay, reverb, etc..). The former are almost mandatory for live miking of vocals.
Summary
How to add two INSERT ¼" phone jacks to this mixer mic channels and allow plugging audio effects (compressors, limiters, echo, reverb, etc..). The former are almost mandatory for live miking of vocals.
Background
The 402 is a great 100$ compact 4 ch. mixer (reviews are unanimous) but lacks sound effect connectivity: no INSERT jacks neither AUX SEND output. For some this precludes using it in live settings and calls for its bigger brother the 802, at twice the price and triple the weight… This project will show you how to void your warranty by inserting INSERT jacks on your beloved 402-VLZ3.
Audience
This project is perfect for the musician wanting to dive into electronics: the electrical part is fairly simple, the mechanical aspect being the most demanding (components placement is critical, space is a premium in this compact mixer).
Skills
This is a beginner occasion to learn how to
- disassemble a mixer
- drill holes in sheet metal
- read simple electrical schematics
- solder cables and contacts
Steps
Step #1: Theory of operation
Next
- You can skip this part if you don't want to understand what you're doing... 8-)
- Lower left image: disassembling the mixer and inspecting the boards show easy access to channel 1 and ch.2 signal path (without cutting any PCB trace) at the exact point where INSERTs are frequently found: after the low-cut filter and before EQ (upper left schematic).
- In the lower right corner, the wires 2 and 4 (marked W2, W4 as silkscreened on the PCB) are signal channel 1 & 2 and will be diverted to the jacks. Wires W1 and W3 are signal grounds and stay intact.
- This is known as a TRS "tip send ring return" configuration, the standard for most recent mixers for unbalanced mono effect insert point. Dashed line in upper-right shematic is cut wire W2. The color code I used is: green, send; red, return and black, GND.
