Voodoo Lab System Mix Plus User Manual

SYSTEM MIX PLUS

Owner's Manual

DIGITAL MUSIC CORPORATION

Table of Contents

________________________________________________________

1. Introduction . . . . . . . . . . . . . . . . . . 2

1.1 Overview

1.2 Unpacking

2. Operation . . . . . . . . . . . . . . . . . . . 3

2.1 Front Panel

2.2 Rear Panel

3. Mixer . . . . . . . . . . . . . . . . . . . . . 6

3.1 Mix 1

3.2 Mix 2

3.3 Setting Levels

1

4. MIDI Volume . . . . . . . . . . . . . . . . . 8

4.1 Connections for the Volume Control

4.2 Using the Volume Control with Ground Control

4.3 Using the Volume Control without Ground Control

5. Recording & PA . . . . . . . . . . . . . . . . 9

5.1 Cabinet Simulator

5.2 Headphone System

6. Putting Your System Together . . . . . . . . . 11

6.1 Two Typical Systems

6.2 Using With a Switching System

Appendix A . . . . . . . . . . . . . . . . . . . 16

Technical Specifications

Appendix B . . . . . . . . . . . . . . . . . . . 17

Block Diagram

Warranty Information . . . . . . . . . . . . . . . 18

DIGITAL MUSIC CORPORATION

1. Introduction

______________________________________________________

1.1 Overview

System Mix Plus is a dual stereo line level audio mixer designed specifically for electric guitar
systems. With System Mix Plus, you can combine the line level outputs of your rack effects with
the pure tone of your amp or preamp. This results in lower noise and better tone.

Additional features have been built in to System Mix Plus to facilitate recording directly into a
studio mixing console or connecting directly to a PA system for live use. These include:

• Speaker cabinet simulation circuitry, switchable for either "2x12 open" or "4x12 closed"

cabinet sounds.

• Balanced XLR outputs.

• A versatile headphone monitoring system with separate volume controls for your signal

and an external feed.

System Mix Plus also features a MIDI controlled stereo volume control, also referred to as a
VCA (Voltage Controlled Amplifier). The volume control, which can be inserted anywhere in
your line level signal path, responds to the Ground Control or any device which can send MIDI
control change messages. This allows you to control your volume without having to run audio
cables out to your volume pedals.

Front-to-back passive feedthrus are provided for four audio feeds and MIDI.

2

1.2 Unpacking

Your factory carton should contain:

1. This manual

2. System Mix Plus

3. Power supply

4. Warranty card

Please fill out the enclosed warranty card and return it to Digital Music Corp. By
registering, you enable us to send you important information about related products, updates
and accessories.

DIGITAL MUSIC CORPORATION

2. Operation

________________________________________________________

2.1 Front Panel

1. Power Switch: Applies power to System Mix Plus.

2. MIDI FEED: Direct passive feed thru to the MIDI FEED on the rear panel.

3. Level LEDs: Indicate output level of Mix 1 and Mix 2, not left and right. The thresholds

are:

+10 dBu (Red)
0 dBu (Yellow)

- 10 dBu (Green)

- 20 dBu (Green) (Note: 0 dBu = 0.775 volt RMS)

When setting levels, the signal peaks should barely light the yellow LEDs. You should

NEVER see the red LEDs. See section 3.3 for more information.

4. MIX LEVEL CONTROLS: Stereo volume for MIX 1 and MIX 2. Unity gain is set with
the knob at 12 o'clock.

5. CABINET SIMULATOR In/Out: Switches the speaker cabinet simulator on and off.
Simulator is on when the button is pushed in.

6. CABINET SIMULATOR Open/Closed: Selects between two different speaker cabinet
types for the sound of the cabinet simulator.

7. BALANCED OUT Ground Lift: Disconnects pin 1 of the BALANCED OUT jacks from
ground when pushed in.

8. BALANCED OUT Phase Invert: Reverses the phase relationship between pins 2 and 3 of
the BALANCED OUT jacks. With the button out, pin 2 is "+" and pin 3 is "-". With the
button pushed in, pin 3 is "+".

9. L - BALANCED OUT - R: Left and Right balanced outputs from Mix 2 or from the cabinet
simulator if it's switched in.

3

DIGITAL MUSIC CORPORATION

4

10. MONITOR Ground Lift: Disconnects the sleeve of the MONITOR IN jack from ground
with the button pushed in.

11. MONITOR Phase Invert: With the button pushed in, the phase of the MONITOR IN signal
is inverted.

12. HEADPHONE LEVEL Direct: Adjusts the headphone volume of your mixer signal.

13. HEADPHONE LEVEL Monitor: Adjusts the headphone volume of the MONITOR IN

signal.

14. MONITOR IN: Accepts a stereo (TRS) plug for headphone monitoring of external signals
(monitor mixes, etc.)

15. HEADPHONE: Stereo headphone output. The impedance of the headphones should be 30
Ω or greater.

16. FEED THRU 1-4: These four separate, passive mono feeds connect directly to the four
FEED THRUs on the rear panel.

2.2 Rear Panel

[Note: All of the 1/4 inch jacks on the rear panel are for mono plugs. Except for the four FEED
THRUs, the top row is for the Left channel of your stereo signal and the bottom is for the Right.
Any mono signals should be plugged into the Left inputs (except for Mix 2 In 1). They will
automatically feed both the Left and Right channels.]

1. POWER: Requires 9 VAC at 1.0 amp.

2. MIDI FEED: Direct passive feed thru to the MIDI FEED on the front panel.

3. MIDI IN: Standard 5 pin MIDI connector. Accepts commands for MIDI controlled volume,

and passes all data to the MIDI THRU jack.

4. MIDI THRU: Standard 5 pin MIDI connector. Outputs all MIDI data that comes in through
the MIDI IN jack.

5. Passive Split: These outputs carry the same signals coming in the "Mix 1 In 1" inputs.
Enables you to feed these signals somewhere else without having to use Y-cables.

6. Mix 1 Inputs: Four stereo, line level inputs to Mix 1.

7. Mix 1 Out: Two identical sets of Left and Right line level outputs from Mix 1.

DIGITAL MUSIC CORPORATION

5

8. Mix 2 Inputs: Four stereo, line level inputs to Mix 2.

Note: Mix 2 In 1 controls the internal connection (normal) from Mix 1 to Mix 2. If nothing is

plugged in to these inputs, the outputs from Mix 1 feed through to Mix 2.

If something is plugged in to these inputs, the internal Mix 1/Mix 2 connection is broken.

9. Mix 2 Out: Left and Right line level outputs from Mix 2.

10. Direct Out: Line level outputs from Mix 2. If the Cabinet Simulator is switched in, these

outputs are affected.

11. Volume - In: Stereo line level inputs to the MIDI controlled volume control. As with the
other inputs, a single cable plugged into the Left input will appear at both output jacks.

12. Volume - Out: Stereo line level outputs from the MIDI controlled volume control.

13. FEED THRU 1-4: These four separate, passive mono feeds connect directly to the four

FEED THRUs on the front panel.

DIGITAL MUSIC CORPORATION