GCX Guitar Audio Switcher OWNER’S MANUAL
Please visit our web site at: www.voodoolab.com Copyright 1998 by Digital Music Corporation. This publication is protected by copyright and all rights are reserved. No part of it may be reproduced or transmitted by any means or in any form without the express prior consent in writing from Digital Music Corporation. Ground Control, System Mix, GCX, and Ground Link are trademarks of Digital Music Corp.
Table of Contents ________________________________________________________ Introduction . . . . . . . . . . . . . . . . . . . 3 Overview Front Panel Rear Panel Unpacking Buffered and Passive Feed Thru's . . . . . . . . 5 Why Use the Buffer? Connection Options Audio Loops . . . . . . . . . . . . . . . . . . . 7 Effects Loops A/B Switching Muting Sends Combining Multiple Amps Using Loops as Switches . . . . . . . . . . . . 10 Latching Type Normally Open vs.
Introduction ________________________________________________________ Overview The GCX Guitar Audio Switcher greatly expands the capabilities of your Ground Control foot controller. With the GCX, you can select pedal effects, signal processors, multiple amps or preamps, amp channels and more. The GCX has two 1/4 inch feed thru's from front to back. The feed thru labeled "GUITAR IN" is buffered to maximize guitar pickup tone quality, minimize noise, and allow signal splitting to drive multiple devices.
Rear Panel • • • • • • POWER - connect to the supplied external AC adapter. PEDAL IN* - receives MIDI data from the Ground Control and sends power to the Ground Control. MIDI OUT - echoes MIDI data from the PEDAL IN. GUITAR OUT - buffered output from front panel GUITAR IN. FEED THRU - passive connection to the front panel FEED THRU. Also duplicates the GUITAR OUT for splitting when the front panel FEED THRU is not being used. IN/SEND/RETURN/OUT - audio connections for each of the eight loops.
Buffered and Passive Feed Thru's ________________________________________________________ There are two front panel feed thru's which provide convenient connection to your switching system. The feed thru labeled "GUITAR IN" is buffered and the the feed thru labeled "FEED THRU" is passive. The passive feed thru is simply hard-wired from the front jack to the rear. The most common use for the passive feed thru is for an "amp out" connection (passing from the back to the front).
The following diagrams show some common examples of buffered feed thru connections. Example 1. Using with one instrument: The guitar signal passes from GUITAR IN to GUITAR OUT. Example 2. Splitting from one instrument to two devices: Since the two feed thru's are normalled together, the guitar signal passes from GUITAR IN to both GUITAR OUT and FEED THRU. Example 3.
Audio Loops _______________________________________________________ Important: GCX audio loops are for instrument and line level signals only. Using them to switch amplifier or speaker outputs will severely damage your GCX. The most important characteristic of an audio switcher is sonic transparency. Some manufacturers implement loops using either optoFETs (optical transistors) or LDRs (light dependent resistors), or a combination of the two.
A/B Switching GCX loops can be used for A/B switching. The following are two examples. Example 1. Selecting between two preamps: When the loop is OFF, Preamp-1 feeds the audio out. When the loop is ON, Preamp-2 is selected. Example 2. Selecting between two amps: When the loop is OFF, Amp-1 plays. When the loop is ON, Amp-2 plays. Muting Sends Loops can be used to mute the input to effects. When the loop is ON, "Audio In" feeds the input of "FX". When the loop is off, the input to "FX" is muted.
Combining Multiple Amps By using multiple loops, combining amps is possible. When loop #1 is ON and loop #2 is OFF, only Amp-1 is active. With loop #1 OFF and loop #2 ON, only Amp-2 is active. When both loops are ON, both amps play at the same time.
Using Loops as Switches ________________________________________________________ GCX loops will act as footswitches like those used for amp channel switching and bypassing signal processors. The GCX supports both standard switch types, latched and momentary. You can also select between normally open and normally closed operation. Latched or momentary modes are selected from your Ground Control (see "Using the GCX with a Ground Control").
However, if the GCX status LED is ON when you want it OFF, you can reverse polarity by selecting normally closed. For example, let's say you're controlling reverb on your amp from its footswitch input, but the GCX status LED is ON when the reverb is OFF. You can fix this by changing from normally open to normally closed (plug into the SEND/N.C. jack). The LED will now show the correct state of the reverb. Momentary Type Some devices require momentary type switches.
Using the GCX with a Ground Control ________________________________________________________ Your GCX is part of the Ground Control System, and is easiest to control with the Ground Control Programmable MIDI Foot Controller. From the Ground Control, you can specify whether each loop should act as an audio loop, latched switch, or momentary switch. You can then control loops individually, as well as save loop settings with each of your 100 presets for instant recall.
1. Enter Setup Mode by pressing both Ground Control [SETUP MODE] buttons at the same time. 2. Press [EXPANDERS]. 3. Press [+/YES] so the display reads "GCX-1 ON". 4. Press [CURSOR >] to access the first loop. To use this loop as an audio loop or a latched switch, press [-/NO] so the display reads "GCX 1=NORMAL". To use this loop as a momentary switch, press [+/YES] so the display reads "GCX 1=MOM SW". 5. Repeat step 4 for each of the eight loops. 6.
Using the GCX without a Ground Control _________________________________________________________ Warning: The PEDAL IN jack on the GCX is not a standard MIDI In. It utilizes the two normally unused pins to provide 9 volts A.C. power for the Ground Control. Before connecting to a device other than the Ground Control, you must either use a cable without pins 1 and 3 wired, or verify that the MIDI Out of that device conforms to the MIDI specification which states that pins 1 and 3 are unconnected.
Warranty NORTH AMERICA ONLY Voodoo Lab warrants this product against any defects that are due to faulty material or workmanship for a period of five years from the date of original retail purchase. This warranty does not include damage to the product resulting from accident or misuse. This warranty is given to the original purchaser only and it is not assignable to any other person.
